# Digi 2: Lets get some serious MAF conversion discussion goin on



## Coupe__88 (Sep 14, 2003)

Us high hp digi guys need to find a cheap proven way to ditch the stock vane air meter . Digi 1? yeah, but I would still like to find a MAF for digi 2, I have found websites with VAM to MAF conversions which i will try to find. Maybe we could find the resistance range for the VAM, find a generic MAF off another car that has a similar range CFM/ohms or something and try that out??? im gonna try to get ahold of some experimental MAFs to take readings and such. anyone have ideas? 
I like Daniel Adams idea of the BMW VAM , very smart, but im looking to get rid of the whole thing. If there is a reliable, accurate , inexpensive way this can be done , i will do it, if not, looks like digi 1 is on the way

until then


_Modified by Coupe__88 at 3:17 AM 10-6-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*


_Quote, originally posted by *Coupe__88* »_Us high hp digi guys need to find a cheap proven way to ditch the stock vane air meter . Digi 1? yeah, but I would still like to find a MAF for digi 2, I have found websites with VAM to MAF conversions which i will try to find.

I am interested in finding a cheap, proven way of switching to MAF too - I am going with the larger vane air meter for the moment as a simpler way to upgrade, but even this isnt plug and play - I've found a larger BMW (Bosch) one that just "plugs in", same 4-wire connector etc (the digi one is Bosch too) but haven't got around to testing the output properly compared to a digi one - I did just hook it up and see if it worked at all when I first got it but no joy - the car would not start with it in place (exactly the same as if the stock VAM was unplugged). When I get time I'm going to get an idea of the output signals from the stock and BMW one and see if I can get it to work. If I do, I will be able to post up the Bosch part number for the larger VAM and the process of converting it to work with the digi.

_Quote, originally posted by *Coupe__88* »_Maybe we could find the resistance range for the VAM, find a generic MAF off another car that has a similar range CFM/ohms or something and try that out???

This is probably a good first step (and, as I say, what I need to do first too) - before i can really go doing anything we need to gather the basic facts about the stock VAM - at a minimum its basic output (resistance) range and at best a plotted curve of output (resistance) vs CFM airflow - don't forget, its no good having an AFM or larger VAM that just has the same output range, *they must be the same output for the same CFM* or else the ECU will do crazy stuff and under- or over-fuel the car at certain revs etc.

_Quote, originally posted by *Coupe__88* »_im gonna try to get ahold of some experimental MAFs to take readings and such. anyone have ideas?

Doesnt the mk3 VR6 have a MAF? That might be a good palce to start since its VAG, we know it can flow to higher hp than the 8v etc. I really think before we go experimenting much further though, we need to get the basic operation of the stock unit nailed down - we need to know exactly what it is we are trying to match. Does anyone have a voltmeter etc? I have to borrow one off my mechanic (he doesnt mind) every time I fart around with stuff like this so its not too easy for me - I really would like to see someone make a plot of CFM vs output (resistance) but I know that this would require some specialist equipment???

_Quote, originally posted by *Coupe__88* »_I like Daniel Adams idea of the BMW VAM , very smart, but im looking to get rid of the whole thing. If there is a reliable, accurate , inexpensive way this can be done , i will do it, if not, looks like digi 1 is on the way


THanks, mate - yep, I would like to get rid of the whole thing too ideally, but my motivation for going with the BMW one for now is that:
a) Its BOsch, the stock one is Bosch
b) plugsin straight away, plug-and-play
c) its still a VAM system, so should have the same output style (linear/non-linear/exponential) as the stock one
d) Might require something as simple as an extra resistor on its PCB to adjust the output range to the perfect signal for ECU
e) I know from the car it came out of that it can flow enough to power an engine that runs 180hp stock, meaning probably it can flow enough to get up to 250hp or so before it again becomes a limiting factor.
Lets keep this discussion rolling, because I think most are agreed this is a big bottleneck on our cars.
Dan

_Modified by DanielAdams at 2:54 PM 10-6-2003_


_Modified by DanielAdams at 5:34 PM 10-6-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

I'm off down to my mechanics now to borrow a multimeter. I will attempt to get a basic idea of the range (but not a full curve of resistance vs CFM) of both the stock VAM and the BMW one.
In the meantime, I found some slight amount of information on the digi VAM system (albeit for the digi vanagon system:








fuelling (injection openeing signals) are provided by a combination of:
- engine speed
- intake air volume
- coolant temperature
- o2 content in exhaust gas
VAM plug wiring (from top, reading left to right), 4 connectors (is it 3 on ours or 4??)
layout: * * * *
connector nos: 6 9 21 17
potentiometer outputs across plugs:
6 & 9 - resistance (intake air temp)
6 & 17 - airflow sensor - total resistance - 500 to 1000 ohms
17 & 21 - AFS resistance - resistance through potentiometer - ohms fluctuate as sensor plate is opened
Dan


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## gearhead455 (Oct 30, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

The only way I see this possible is to put both sensors on a cylinder head flow bench and map the voltage outputs compared to CFM or inches of water.


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (gearhead455)*


_Quote, originally posted by *gearhead455* »_The only way I see this possible is to put both sensors on a cylinder head flow bench and map the voltage outputs compared to CFM or inches of water.

Hi gearhead, was wondering how ong it'd be until you waded in here








That would be ideal, yes, as I said above, and if anyone does have access to the equipment, this would definitely be the best path to take. However, if you get a larger Bosch VAM (rather thana MAF) you could assume that the resistance output would follow the same pattern and if you matched the resistance of the stock and replacement VAMs at a *single* CFM, the overall output pattern would match too - so all you need to do is get an identical resistance at the same CFM by adjusting the replacement resistance through the VAM spring. A single CFM could be applied to both in any number of ways - fan, hairdryer, hoover








This could be veririfed by then hooking up a probe at a garage to check fuel/air at every rpm.
Madness?
Dan


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## gearhead455 (Oct 30, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

My head hurts now, thanks.








It would be ideal if the VAM and MAF had a linear output. But I have no idea if it does.
If they where linear than you could set up a base reading with a vacuum cleaner, adjust the resistance to match the VAM and off you go. But what if the VAM and MAF outputs curve at different rates? It may be easier to program a EPROM to read a MAF rather than trying to modify a MAF to mimic a VAM.
There.... now your head hurts.











_Modified by gearhead455 at 4:14 PM 10-6-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (gearhead455)*

Aaaaaargh! Death to acronyms!









_Quote, originally posted by *gearhead455* »_
It would be ideal if the VAM and MAF had a linear output. But I have no idea if it does.

Yup, this is a pretty important 'If" - we definitely need to plot the CFM/ohm graph for the stock'un and pray its linear. I'm collecting a multimeter from my mechanic's tomorrow morning (GMT







) and I'll be able to plot a simple graph but one that should be enough to tell if its linear or not.

_Quote, originally posted by *gearhead455* »_If they where linear than you could set up a base reading with a vacuum cleaner, adjust the resistance to match the VAM and off you go.


Yup, thats exactly what I was hoping - was expecting some ridicule for the hoover/hair dryer idea though ;-) One problem, though - presumably, the internal table of possible resistance values for the VAM (which the ECU reads to calculate fuel injector values) will have a maximum value (say 1000ohms). If you peg the resistance of each VAM at a sample CFM, then there comes a point (say when the replacement VAM is 3/4 open) when it is giving a reading of 1000ohms ( value the stock VAM would max out at). What happens when you mash the pedal a bit more? ie, the VAM is flowing more air so we want the ECU to provide more fuel - however, the CPU might not understand "1200ohms" if it isnt in its table.
If you need to modify the VAM resistance you could:
1) adjust the AFM spring - but then, whilst you have reduced the resistance range to stock, by adjusting the spring's resistance, you have made the resistance curve non-linear (or at least altered its curvature).
2) add in a resistor - but then the max might be out of bounds off the top of the ECUs VAM resistance table.

_Quote, originally posted by *gearhead455* »_
But what if the VAM and MAF outputs curve at different rates? It may be easier to program a EPROM to read a MAF rather than trying to modify a MAF mimic a VAM.


Ouch. I agree, the VAM and MAF outputs are unlikely to curve at the same rate and you probably would be looking at custom EPROM or something (yuck) so I'm pinning hopes on the two VAMs (both Bosch) having similar output curves (hopefully linear).
I think I can now see why the guy who posted a while back about possibility of an 8v MAF estimated such a high price - a replacement VAM is childsplay in comparison.
*EDIT: Let's try and find out as much about the stock VAM system as we can and, as importantly, exactly what digifant does using the resistance values the VAM outputs. I think we need to understand exactly how it works before we undertake anything* 
My head hurts.
Dan


_Modified by DanielAdams at 4:10 PM 10-6-2003_


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (gearhead455)*

i think i found a resistance chart for the VAM , i will post up when i get back from class


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## gearhead455 (Oct 30, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*


_Quote, originally posted by *DanielAdams* »_ - was expecting some ridicule for the hoover/hair dryer idea though ;-)

Well, since this whole discussion is an exercise in "cheapness" (power per $) it sounds like a good idea. I mean if we had money for flow benches that would be great... but if I had all that cash I would just buy a stand alone fuel injection and not worry about a MAF or VAM.

_Quote, originally posted by *DanielAdams* »_ *EDIT: Let's try and find out as much about the stock VAM system as we can and, as importantly, exactly what digifant does using the resistance values the VAM outputs. I think we need to understand exactly how it works before we undertake anything*

Agreed... I mean I don't even know how to comment on this stuff. I could have my head way up my rear and not even know the difference.


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (gearhead455)*


_Quote »_
Digifant ... combined digital fuel control as used in the earleir Digi-Jet systems with a new digital ignition system..... Fuel injection control is digital electronic. It is based on the measurement of *engine load (Air Flow Sensor)*, and on engine speed (Hall sender). *These signals are compared to a map, or table of values*, stored in the ECM memory. The amount of fuel that Digifant provides is based on values taken from a program in the ECM that has *16 points for load*, and 16 points for speed. These 256 primary values are than modified by coolant temperature, intake air temperature, O2 content of the exhaust, battery voltage, and throttle position to provide 65,000 possible injector duration points. Fuel injectors are wired in parallel, and are supplied with constant system voltage. The ECM the ground on and off to control duration.
All injectors operate at the same time, each crankshaft revoloutionl; two complete revoloutions being needed for each cylinder to recieve the correct amount of fuel for each combustion cycle. Digifant has the ability to modify ignition timing at idle to further enhance idle quality


OK, so some more information here - it looks like there is a table of 16 possible resistance values from the VAM, presumably rounded up from the true value read and interpreted as one of 16, in the range of around (based on stated 500-1000ohm range) 500, 530, 560, 590, 620, 650, 680, 710.... 1000 ohms. 
Ok, so it looks like (to answer my own question) it is no use having the replacement giving values of 1200 ohms (say) when fully open. For argument's sake, say 1ohm=1CFM (i know, i know, but just for simplicity) - so the stock VAM is fully open when 1000CFM is flowing and gives a reading of 1000ohms. NOw the replacement, be it MAF or VAM, will hopefully flow a max of (say) 1200CFM, derestricting our airflow 20%. However, it can only signal the ECU it is getting 1000CFM, causing a lean situation. This would need to be addressed.
One more piece in the puzzle...
Dan



_Modified by DanielAdams at 5:27 PM 10-6-2003_


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

great posts guys, we are gonna get this. 
WHAT ABOUT THIS IDEA?-
Im thinking, get the resistance values from the VAM from rest to the point where it is pinned open and starts using RPM based fuel mixtures. 
Take these values and find a potentiometer that falls within spec (might the Digi 1 throttle body potentiometer work? ) mount this potentiometer on the throttle body, it will send a resistance value to the ECU equivalent to what the VAM normally reads without being a restriction, 
While doing this , retain the factory air temp sensor and mount it in the rubber intake snorkel somehow. ???? 

just a thought, ...... still researching. 
we would need to measure resistance with engine on at idle, 1/2 throttle and full throttle ( just need to take readings with air flowing, to adapt to our own particular engines maybe) 

This method could be tested by finding an appropriate potentiometer ( volume knob etc) and using it with an air/fuel meter. 



_Modified by Coupe__88 at 5:59 PM 10-6-2003_


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

ANOTHER IDEA- Use the guts of the VAM on top of the throttle body AS a potentiometer, consideration of load and vaccum are getting me down. 
edit: vaccum controlled diaphram with potentiometer on it? this would sense load.
.....
Heres some resistance test results, maybe we could graph this ?
As tested from pins 2+3 
variances are going to be present from cleanliness etc but these are my readings .
REST: .561 K ohms
point 1: .900 K ohms
point 2: 1.000 K ohms
point 3: .900 K ohms 
point 4: .900 K ohms 
point 5: .730 K ohms
point 6: .700 K ohms
point 7: .650 K ohms
point 8: .600 K ohms
point 9: .520 K ohms 
OPEN: 335 ohms 

test points are the 10 contacts on the PCB inside the VAM between REST and OPEN

_Modified by Coupe__88 at 6:24 PM 10-6-2003_


_Modified by Coupe__88 at 6:53 PM 10-6-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*


_Quote, originally posted by *Coupe__88* »_ANOTHER IDEA- Use the guts of the VAM on top of the throttle body AS a potentiometer, consideration of load and vaccum are getting me down. 
edit: vaccum controlled diaphram with potentiometer on it? this would sense load.
....."

Your first idea (mounted on TB) I would have two concerns about - firstly, it would measure "demand" (you mashing TB) rather than "load", second it would be difficult to mount cleanly and correctly to give good readings. Your revised (edit) idea I don't quite understand, could you explain a bit better?

_Quote, originally posted by *Coupe__88* »_Heres some resistance test results, maybe we could graph this ?

I'll try and get the results graphed and uploaded -
EDIT: done








its not what I expected though, I was expecting something far more linear between rest and fuly open - if those points are all in order the brush sweeps them between rest and open I don't quite understand the non-linearity - obviously, the ECU is getting the same signal at rest as it is at just before near fully-open. I mean, if low resistance correlates to high fuelling (there must be a simple correllation like this because of the lookup table) why on earth is there a lot of fuelling at what must be idle, which is then cut at just off idle as expected? I just don't get that "rest" figure - the rest makes sense.
Dan


_Modified by DanielAdams at 7:19 PM 10-6-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*


_Quote, originally posted by *Coupe__88* »_Im thinking, get the resistance values from the VAM from rest to the point where it is pinned open and starts using RPM based fuel mixtures. 

I think the ECU looks up load (VAM value) and speed (rpms) concurrently to find a single fuel injection value in the table, I don't think it switches to RPM-based mixtures after the VAM is pinned open - as far as I understand, it will always look up VAM and RPM values at every instance.
I think we're making a damn good attempt at having a stab at this so far, I just wish I could have a 15min chat with the digi designers and chip programmers








Dan
Dan


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## need_a_VR6 (May 19, 1999)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*


_Quote, originally posted by *DanielAdams* »_I don't think it switches to RPM-based mixtures after the VAM is pinned open - as far as I understand, it will always look up VAM and RPM values at every instance.


Every vane system that Bosch designed works that way. Digi2 is more or less L-Jet for VW's so it would be true for that too. The flapper gets pinned at about 4000rpms at full load at WOT. Unfortunatley a MAF conversion isn't going to help you where you need it most.. high rpms and full throttle.


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

Ha, i double the chat with digi engineers. the Idle switch and full throttle switch may have an effect on the VAM, my theory is that both of these switches turn off the VAM signal and use the idle circuit and full throttle rpm/temp mixtures just my thoery though. yeah, the throttle / potentiometer would need a load value mixed in, my revised idea would be similar to the cruise control vac. diaphram. the engine vaccum between the filter and throttle body could be measured. and have the diaphram collapse while moving a pin across a potentiometer . this would definiatly be the way to get a reading for load, and thats all the VAM is really for right? 
i am going to try to run with the full throttle switch closed, while disconnecting the 2 and 3 pins on the VAM so that only the intake temp gets read. this is to test my theory that the ECU starts determining mixture by RPM/temp when the full throttle switch is hit
if thats the case then all mixtures will be rpm based (this is all my theory, if we only knew 100% how the system works)




_Modified by Coupe__88 at 7:33 PM 10-6-2003_


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## gearhead455 (Oct 30, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*


_Quote, originally posted by *DanielAdams* »_
I'll try and get the results graphed and uploaded -
EDIT: done








its not what I expected though, I was expecting something far more linear between rest and fully open - if those points are all in order the brush sweeps them between rest and open I don't quite understand the non-linearity - obviously, the ECU is getting the same signal at rest as it is at just before near fully-open. I mean, if low resistance correlates to high fueling (there must be a simple correlation like this because of the lookup table) why on earth is there a lot of fueling at what must be idle, which is then cut at just off idle as expected? I just don't get that "rest" figure - the rest makes sense.
Dan


Stab in the dark...
Actually I can kinda understand why there is a curve like that. If the throttle position is closed (TPS signal) and the resistance value is less than 900 ohms than the ECU knows the engine is at idle and maps accordingly. A soon as the throttle position shows off idle and a resistance value that jumps to 1000 ohms and then lowers, it know that the engine is being revved.


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (need_a_VR6)*


_Quote, originally posted by *need_a_VR6* »_
Every vane system that Bosch designed works that way. Digi2 is more or less L-Jet for VW's so it would be true for that too. The flapper gets pinned at about 4000rpms at full load at WOT.

OK, thanks, I stand corrected.

_Quote, originally posted by *need_a_VR6* »_Unfortunatley a MAF conversion isn't going to help you where you need it most.. high rpms and full throttle.

How do you figure that exactly? It seems to be pretty universally agreed that theVAM is the primary restrictor of airflow in the digi system and a MAF or larger VAM can flow more air. You said yourself that the VAM is pinned open at 4k rpm at full throttle, so thats an admittal it must be really gasping for more air at 5k rpm. This seems to be confirmed by my (and others) experience on the dyno - right about 5k rpm the power and torque begin to fall off.
Surely at high rpms at full throttle is the *only* place a replacement VAM is going to help - at half throttle at 300 rpm, the stock VAM is easily able to flow enough air. Its when its pinned open and the engine can't get enough air that a larger VAM comes into its own.
Provided we can find a less restrictive VAM alternative (easy) and a way to make it get along with the ECU (both in accurately reprensting airflow as resistance, and also in making the ECU increase fuelling to match) I can't see a problem.
Why, specifically, do you think a larger VAM/MAF will not help? That's the first opinion like that that I've come across/
Thanks for chipping into the discussion, BTW, i wish a few more people would get involved.
Dan


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*


_Quote, originally posted by *Coupe__88* »_.... and have the diaphram collapse while moving a pin across a potentiometer . this would definiatly be the way to get a reading for load, and thats all the VAM is really for right?

The VAM serves two purposes - monitoring load (airflow, meant to be an approximation of oad, but is not exact) and monitoring intake air temp. This diaphragm idea still sounds pretty complicated to me.

_Quote, originally posted by *Coupe__88* »_i am going to try to run with the full throttle switch closed, while disconnecting the 2 and 3 pins on the VAM so that only the intake temp gets read. this is to test my theory that the ECU starts determining mixture by RPM/temp when the full throttle switch is hit
if thats the case then all mixtures will be rpm based (this is all my theory, if we only knew 100% how the system works)

Wow, OK, do you mean yo're going to try this for real? Will your car not just flood with the ECU giving it WOT fuelling and fail to start? I think from what you and need_a_VR6 say tho that between us we have now built a basic model of how the system works








Dan
_Modified by Coupe__88 at 7:33 PM 10-6-2003_[/QUOTE]


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## gearhead455 (Oct 30, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

I got an Idea,
Throw the MAF VAM ... whatever... strait into the trash can. Unplug the O2 and run it in open loop... voila! Digi 1.


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

test results : runs pig rich @ low rpm , runs great at high RPM
-------------------------------------------------------------------------------
I am thinking that there are only 3 ACCURATE ways to do this 
1) find a true hotwire MAF made for our cars ( heck, if we can hack into the digi and understand it a little more we may be able to make our own)
2)Digi 1 
3) Daniels idea of the larger VAM.
-stock Digi 2 VAM guts 
-Bigger VAM body
This is how i see it. Does anyone agree/ disagree / have any other ideas???
--------------------------------------------------------------------------------------
you would need to make it proportional 
with variables.. pretend the digi head, throttle body etc was designed to pull "A" cfm's of air, the VAM would be designed with "A" cfm's of air in mind for the tension of the spring inside "K". you can tension the spring all you want , but the size of the VAM body is still the restriction 
therefore. 
with modifications, ( compression, displacement, headwork, camshaft etc )
you would need to measure your engines airflow "B"cfm's over stock "A" cfm's
and find a proportional VAM body to compensate. spring tension "K" would have to be modified accordingly ( tensioned i would assume) 
the same resistance values of the stock VAM are used its is just the airflow and spring tension that are increased proportionally to allow it to behave in a stock manner with increased potential air volume from the larger body
------------------------------------------------------------------------------------
make sense? didnt think so







nah, just more insight that might help us proceed
Daniel, i will definiatly help you out as much as I can with your VAM idea until i can find out a Hotwire MAF idea. 

hahaha! good one gearhead oh man. dont give me any crazy ideas now








-----------------------------------------------------------------------------------------
extra note on the Hotwire MAF idea..... Digifant pulls injector duration from a table which is stored in the chip . If the increased air coming in exceeded the parameters on the data table then the table may need to be modified or expanded for the increased airflow. mkrad can burn chips and seems to be a genious at this kinda thing. just a note. 


_Modified by Coupe__88 at 8:37 PM 10-6-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

OK, can someone explain to me exactly what digi I is? I understand that you lot over the pond have digi II, and I've always assumed my digifant was "digi II' also but I don't have an o2 sensor on my digifant setup, and no cat. Am I digi I? Or a bastardised Euro-digi II? My digifant chip number is JL2764HS/301002. I'm beginning to wonder...
Dan


_Modified by DanielAdams at 8:54 PM 10-6-2003_


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## need_a_VR6 (May 19, 1999)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

Honestly at full tilt I doubt the VAM is the restriction. I'm almost sure the intake manifold is, if not that then it's the head. The mods might be worth it at that point, but how much are you going to gain, and for what level of work and cost. 
Deleting the VAMs biggest gain would be IF you could map full throttle tables relative to mass air. But you can't do that on Digi anyway unless you find a way to remap it. 
Hate to be "that guy" but I'm just trying to toss out things you guys might not have thought about yet.
Edit: to measure the true restriction of the VAM at WOT, put a pressure gauge across it. If it's more then 2-3" of vacuum then it's enought to be worth ditching.


_Modified by need_a_VR6 at 4:06 PM 10-6-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (need_a_VR6)*


_Quote, originally posted by *need_a_VR6* »_Honestly at full tilt I doubt the VAM is the restriction. I'm almost sure the intake manifold is, if not that then it's the head. The mods might be worth it at that point, but how much are you going to gain, and for what level of work and cost. 

I appreciate the manifold and head are restrictors but I don't see them as being a bigger problem than the VAM, I mean the profile of the VAM opening is just ridiculously small. In any case, the head and manifold on many's cars have been worked over, which makes it all the more likely the VAM has become the bottleneck. We're just going to have to agree to disagree. As I've always said, I'll go and get the car dynoed after I've succeeded in the VAM swap and, since i have a "before" plot from the same place, we'll see what the result it. I may well have to eat my hat, but I hope not.

_Quote, originally posted by *need_a_VR6* »_Deleting the VAMs biggest gain would be IF you could map full throttle tables relative to mass air. But you can't do that on Digi anyway unless you find a way to remap it.

It would certainly nice to be able to remap the ECU completely after swapping the VAM - that's what Brian's comment about mkrad and (to a lesser extent) talking about changing VAM spring tension or adding resistors is essentially trying to do.

_Quote, originally posted by *need_a_VR6* »_Hate to be "that guy" but I'm just trying to toss out things you guys might not have thought about yet.

It's ok, I never listen to the voice of reason anyway. Part of this is to remove the restriction in the air intake, another big part is just because I want to understand how it works and enjoy modifying my car in any which way.

_Quote, originally posted by *need_a_VR6* »_Edit: to measure the true restriction of the VAM at WOT, put a pressure gauge across it. If it's more then 2-3" of vacuum then it's enought to be worth ditching.

Wouldnt that tell you the totel vacuum, not the VAM restriction? ANy restriction you measure that way could, as you point out, be provided by the manifold, right? Or am I just not understanding how a pressure gauge works?
Dan


----------



## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (need_a_VR6)*

VR.. the input is much appreciated .
from what I understand the difference of Digi 1 is the ECU has BPS (barometric pressure sensor) built into the ECU, a Throttle position sensor and then some. i know that to run N/A digi 1 you need an SNS chip. Digi 1 came on corrados and supposively vanagons, but the digifant 1 service manual shows a vangaon setup identical to my digi 2. I am trying to get ahold of a guy in my area who has converted to digi 1, take it for a ride, and see what he has done.


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

SNS tuning, this site makes me happy
http://snstuning.com/chiptuning.htm


----------



## Red Cab (Sep 3, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

For starters the air flow to ohms relation is NOT linear in a vane type meter. You will get more air than ohms change at higher flow rates. I don't know if the relationship is logaritmic or exponential. Why not just get away from AFM or MAF and just go with MAP? That imposes no restriction on the air flow.


----------



## need_a_VR6 (May 19, 1999)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*


_Quote »_Wouldnt that tell you the totel vacuum, not the VAM restriction? 

That's why I said to put the gauge ACROSS the VAM, so you're measuring the pressure before and below and the gauge is subtracting them. Obviously you'll need a differential pressure gauge (one with two ports) to do this test, and not a normal vac gauge. I'd honestly do this test before you do anything else, it'll really tell you what gains are to be had by changing to MAF.


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

supposedly these guys are working on a Mass Air Conversion
check em out @
http://www.pro-flow.com/Import/import front.htm 
My power peak came in at 5,000-5,100 rpm also.
I was going to try the BMW vane meter route too, I found the meters from the BMW 3.5L 6cylinders to be larger. Ex)BMW 535i, 635i, 735i


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## mrkrad (Nov 9, 2000)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (need_a_VR6)*

i've had a our uk guys look at the variations of chips we've produced and some chip he had gotten in uk.
results:
1. stock chip lean as hell
2. chip with less lag (unnamed) - lean as hell
3. my first modded chip - not quite lean but lean as hell
4. 2,3,4th, less lean, richer, richier.







but still leaner than i think is nominal.
Which brings me to the 3.5+ bar fpr mod. Why not just wank in more FPR first. It seems at 3.0bar the injectors do end up going static, and lean out up top regardless of programming (stock car, no cam, no exhaust other than hole).
If you want a nice rich mixture to run mad base timing with 93 octane, you're gonna have to up the fuel pressure. I'm gonna try one more BALLS out chip, but the results of the generations of digi-2 chips leave me in quandry. The stock and (unnamed) modded chip ran like 14:1 across the whole rpm spectrum. I'd prefer something along the lines of 13:1 across the ball, which would allow you guys to run higher octane and significantly more timing (Dizzy).
Haven't dyno'd these but i spose if i ever find someone in atlanta i'll whip up a batch and spend an hour on the dyno to try them out and see whats up.
The idea being with more richness, more timing, and more octane,(and cam/etc) you'll find the sweet spot. Running 6200rpm with 14:1 is dangerous imo. Any chiptuner knows that. Hell if i had my way above the PEAK WHP range of the digi-2 heads i'd shoot for 12.5:1 to keep the valves from melting down. 
The digi-2 head unlike the g60 head does not have sodium filled exhaust valves.
Check your plugs sometime.
clean them off wire brush, bring your tools. Make several high rpm runs (meaning holding it up there) then stop immediately,no more then a minute or so, and pop all the plugs out and show me what you see.
Your valves will reflect your plugs.
thats just my opinion. Due to no digi-2 car in atlanta to play with, i've really not had much attention to this car.
But you guys are probably running leaner than you think.
Which limits your base timing and 93 octane, and causes excess EGT's.


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Red Cab)*


_Quote, originally posted by *Red Cab* »_For starters the air flow to ohms relation is NOT linear in a vane type meter. You will get more air than ohms change at higher flow rates. I don't know if the relationship is logaritmic or exponential. Why not just get away from AFM or MAF and just go with MAP? That imposes no restriction on the air flow.


Yes, but could you get a MAP sensor to work with digifant? The further away you get from the stock VAM (BMW-VAM -> MAF -> MAP) the more difficult its going to be to get the rig up and running.

_Quote, originally posted by *Digiracer* »_supposedly these guys are working on a Mass Air Conversion
check em out @
http://www.pro-flow.com/Import/import front.htm 


OK, I see they do aftermarket MAFs with a converter to change voltage signal to resistance the ECU can read. This could be a possibility, but from what I see they're going to hit the same problem as a larger VAM - they claim they:

_Quote, originally posted by *pro-flo* »_help add power through this conversion because we allow your engine to breathe easier by flowing more air

but if this is the case, the engine eill lean out at load using this system, just as we foresaw using our hacked-together BMW VAM or rigged-up MAF. The only solution they offer to this is to "upsize your injectors" (as mrkrad discusses as part of upping your fuelling) The big plus to going with this system is that maybe if enough of us group-buyed it oculd be cheap, and it would relieve us of having to get the VAM/MAF talking to the ECU (what we foresaw as the hardest par of all this). What do others think?

_Quote, originally posted by *Digiracer* »_My power peak came in at 5,000-5,100 rpm also.
I was going to try the BMW vane meter route too, I found the meters from the BMW 3.5L 6cylinders to be larger. Ex)BMW 535i, 635i, 735i 

Cheers for chipping into the discussion mate, its good to see a few more people getting their teeth into this - it definitely looks like we're all hitting the exact same problem and coming up with similar solutions. THE BMW VAM i have here is out of a 535i too - the part is probably common to all three models.

_Quote, originally posted by *mrkrad* »_lots and lots of stuff

Ok, that's a pretty hefty post - addressing the fuelling side I guess rather than strictly the problem of getting a MAF or larger VAM to work. Still, the fuelling side is important as we've seen if the car isnt going to lean out with a larger VAM/MAF under full load. I have two quesitons for you mate:
1) Is the 3.5bar FPR mod a G60 FPR or similar?
2) Would it not be necessary to upgrade the injectors simultaneously?
WHen I had my digi on the dyno I was pretty shocked at how lean it was running at first, I would agree these cars do seem to run pretty lean even stock.
Dan

_Modified by DanielAdams at 9:30 AM 10-7-2003_


_Modified by DanielAdams at 9:33 AM 10-7-2003_


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

you would think the o2 would try to compensate


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## Red Cab (Sep 3, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*


_Quote, originally posted by *DanielAdams* »_

but if this is the case, the engine eill lean out at load using this system, just as we foresaw using our hacked-together BMW VAM or rigged-up MAF. The only solution they offer to this is to "upsize your injectors" (as mrkrad discusses as part of upping your fuelling) The big plus to going with this system is that maybe if enough of us group-buyed it oculd be cheap, and it would relieve us of having to get the VAM/MAF talking to the ECU (what we foresaw as the hardest par of all this). What do others think?


Yes the engine will lean out. Any engine will if you just pump more air through it. The computer is programmed to compensate upto a certain range. After that it will stop increasing the duty cycle on the injectors.
So you are left with three things to do. One is to change the injectors and two reprogram the ecu. These two make up the best method. The third is to boost fuel pressure but that is not valid if you need to increase by more than 5psi.
Then we come to the though of aftermarket programmable ecu's. These are the most flexible and some will allow you to choose which air sensing element you want to use. However if you dont have a top quality exhaust gas analyzer, you can destroy your engine while programming.


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Red Cab)*

I managed to get the resistance of the BMW VAM plotted - results and a graph of the resistance curve against the stock digi curve are below. The resistance was measured against pins 2 and 3.








I was surprised to find that the results were almost identical to those Brian found using the digi VAM - clos4e enough that you'd think it'd be possible to do a straight plug-and-play swap without any adjustment. Of course, whilst the ECU would be getting identical readings per degree the VAM was open, more air would in fact be flowing through (as discussed above) and hence the engine would run lean.
I'm now not sure why my engine did not run when I initially hooked up the BMW VAM to test it - it seems like it should have run (albeit lean). I will have to try again, perhaps I simply had not connected the plug correctly or perhaps the BMW VAM air temp sensor is different - I will have to take some more readings and try again.
In any case, the BMW VAM looks like being a pretty straightforward swap that might entail simply raising the fuelling using a higher bar FPR or similar as discussed by Red Cab and mrkrad above.
The BMW VAM is, for those who haven't seen it, substantially greater-flowing than the stock one.
Dan



_Modified by DanielAdams at 10:35 AM 10-9-2003_


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

whoa ! good stuff Daniel! have you compared the pins between the 2 VAM's ? might there be 2 switched around? and is this from the 533i? what is the part number on it, it may be the same for the 2.5 or 2.8???.
Im wondering if spring tension is different on the 2 VAM's from the different engine vaccum pulling on it. You may want to get an adjustable FPR and dial it in that way. sounds promising to me so far. Im going to source some adjustable FPR's , I need one for a Digi 2 16v swap anyhow. BiZzUmP bIzZaTcH always wanted to do that
----------------------------------------------
(later that day)








-----------------------------------------------
heres an adjustable FPR for $139USD
http://www.8vturbo.com/product...at=18
Then again it might be good to take a shot in the dark with a
cheaper non adjustable FPR and step up or down from there. 

_Modified by Coupe__88 at **** PM 10-9-2003_


_Modified by Coupe__88 at 4:26 PM 10-9-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*


_Quote, originally posted by *Coupe__88* »_whoa ! good stuff Daniel! have you compared the pins between the 2 VAM's ? might there be 2 switched around?

Quite possibly, 2+3 are airflow resistance, as with the digi. I got a 560ohm reading off another two pins (constant) that woulld've been perhaps the air temp sensor?? But I can't recall which pins it was - I'll list the pin combo functions completely for the BMW tonight when I have a achance to take the multimeter to it again - if you could do the same for digi that's be great. I'm pretty excited this imght be a straight swap with a FPR.

_Quote, originally posted by *Coupe__88* »_and is this from the 533i? what is the part number on it, it may be the same for the 2.5 or 2.8???.

I got mine from a 535i (3.5l V6) - essentially the same engine as the 533i, just slightly larger displacement in a different model year. The part stamped on the top is "BOSCH 0 280 203 016" (persumabley the bosch part no.) and then on the bottom is "1 285 501 (possibly the BMW part number?).
I cannot remember the year BMW I pulled it from, I think it was probably late 80s-early 90s?

_Quote, originally posted by *Coupe__88* »_Im wondering if spring tension is different on the 2 VAM's from the different engine vaccum pulling on it.

I want to try the "hoover" trick on the BMW VAM later today and see what readings it gives, but don't have a digi VAM off a car to compare it to - if I can be bothered, I'll remove my digi VAM and get a comparison reading too of resistance/position under "hoover" load









_Quote, originally posted by *Coupe__88* »_You may want to get an adjustable FPR and dial it in that way. sounds promising to me so far.

I'm pretty confident it will work now and possibly just run lean until I fit a FPR. Thanks for listing that one, I'll see if I can find any others online too. I'm most interested right now in figuring why on earth it didnt run when I first tested it. I suspect either I didnt plug it in properly (Or perhaps at all!







) or else the wires for air temp sensor might be different.
I'll post up those wire combos later http://****************.com/smile/emthup.gif
Anyone else down with the BMW VAM based on this promising start or are you all holding onto your wallets 'til someone develops a MAF???








Dan


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

OK, here's the pin readings off the BMW VAM:
pins labelled 1-4, reading left to right on plug with PCB cover facing upwards:
1+2 - 560ohms steady resistance, not affected by air flap (temp sensor?)
1+3 - 11ohms, vaires around 10-600 with air flap opening
1+4 - "out of range"/nothing
2+3 - resistance taken as air flap reading (as in above threads)
2+4 - "out of range"/nothing
3+4 - "out of range"/nothing
I'd like to see how this compares to the digi VAM. I don't understand why 1+3 and 2+3 both give an air-flap dependent resistance reading...
Brian, could you post up the digi pin combos? If not, I'll pull my digi VAM at some point and try and get the results.
Dan


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

from left to right ( airbox side to throttle body side) 
1+2 - 548 ohms steady resistance, not affected by air flap 
1+3 - between 60-98 ohms not consistant up to 1000ohms when opened
1+4 - 2200 ohms
2+3 - resistance taken as air flap reading (as in above threads)
2+4 - 2775ohms
3+4 - 2300 ohms 
pin 3 will always give a flap based reading since it connects to the needle of the potentiometer. 
note: this was taken with a digital auto ranging meter, on a VAM that worked in the car, but i messed with spring tension and disassembled it etc. 
big ups to Dan and all who have helped in researching this, surely more has been experimented and found out than the past 2 years that ive been on here.


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## Red Cab (Sep 3, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

Definitely use an adjustable FPR. Dont get a fixed reg since you cant tune it. I don't remember who asked but the AFM from the 325 (M20 engine) is not the same as that of the 535 (or any M30 variants). The AFM from the M30 engines is larger. Far larger than a 1.8 liter engine would need unless you are making ugly amounts of horsepower.
Another piece of info, you can adjust the tension on the flap by removing the black cover. You will want to approach this in small increments and be sure to mark the original location on the cog before attempting to make an adjustment. If you lessen the tension of the spring you will richen the mixture.


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Red Cab)*


_Quote, originally posted by *Coupe__88* »_from left to right ( airbox side to throttle body side) 
1+2 - 548 ohms steady resistance, not affected by air flap 
1+3 - between 60-98 ohms not consistant up to 1000ohms when opened
1+4 - 2200 ohms
2+3 - resistance taken as air flap reading (as in above threads)
2+4 - 2775ohms
3+4 - 2300 ohms 


OK, so still no real difference at all then - I got "out of range" readings because I was only using the multimeter in 2000ohm range.

_Quote, originally posted by *Red Cab* »_Definitely use an adjustable FPR. Dont get a fixed reg since you cant tune it. 

I'm going to try and get one next week, and fit it and the BMW VAM simultaneously at the garage that I got dynoed at - they have all the proper equipment to hopefully tweak the FPR to make the VAM and FPR work together. I think I'm going to ave to review everything everyone's written above (a lot to try and remember!) but I think I'm about ready to give getting this VAM to work a go http://****************.com/smile/emthup.gif 
Dan


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## FastLapRSII (Jul 15, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

Nice work y'all. http://****************.com/smile/emthup.gif


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (FastLapRSII)*

heck yeah Dan, what day do you expect to have this thing on the dyno?
good luck, i hope our efforts pay off here


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*


_Quote, originally posted by *Coupe__88* »_heck yeah Dan, what day do you expect to have this thing on the dyno?
good luck, i hope our efforts pay off here

I'll have it dynoed at the same time i have it set up, I just need to source an adjustable FPR and find enough spare time etc to do it properly.
I will of course post full results etc whatever happens
Dan


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## Guidofester (Aug 28, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

Seem like such a waste of time. So many others have tried before you. I like my digi system, and I'd really like to be able to modify or upgrade it. I thought about obtaining a Digi 1 setup but they seem to be so hard to locate. I questioned Mrad from S and S Tuning about this and he suggested Stand alone, or Mega Squirt.
I did a search and a Mega Squirt fuel injection system is very reasonably priced. Mega Squirt seems very similar to Digi 1. Very tuneable for your specific application. You guys seem to have a good understanding of how the system works. I'd like to hear from people that have installed MS on VW.
Any of you guys have any experience with Mega Squirt?


_Modified by Guidofester at 6:03 PM 10-11-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Guidofester)*


_Quote, originally posted by *Guidofester* »_ Seem like such a waste of time. So many others have tried before you. I like my digi system, and I'd really like to be able to modify or upgrade it. I thought about obtaining a Digi 1 setup but they seem to be so hard to locate. I questioned Mrad from S and S Tuning about this and he suggested Stand alone, or Mega Squirt.
I did a search and a Mega Squirt fuel injection system is very reasonably priced. Mega Squirt seems very similar to Digi 1. Very tuneable for your specific application. You guys seem to have a good understanding of how the system works. I'd like to hear from people that have installed MS on VW.


Hi. We're not looking for the ultimate setup here, we're looking for something thats relatively easy, relatively cheap, and relatively stock. With something like Megasquirt, you have to hack into your stock wiring loom, you have to know exactly what you're doing, and you lose all semblance of a stock motor with the knowledgebase that accompanies it. The basic motivation for our attempt to upgrade the MAF is that we (I, at least) like the basic digifant setup but simply want to remove one limiting factor of it. It's no more a waste of time than, say, upgrading your brakes to 16v brakes - isnt that a waste of time since you COULD upgrade to four-pot Porsche brakes? Isn't having an 8v motor at all a waste of time, because you COULD upgrade to a twin-turbo VR6? Its all a matter of what your goals are and how much yo're willing to spend towards it.
Total cost so far - $20 for a secondhand BMW VAM, free loan of a multimeter.
Dan


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

I love digifant 2's simplicity and cleanliness in the engine bay and if given $1500 , it would be invested in suspension rather than a new injection system since I am aiming my cars talents toward autocross Waste of time? some may think, but the results may change many minds in the future as Daniel and I are testing and experimenting with what may be a new hope for high performance Digifant, or may just be a failed attempt . If nothing else this will leave us, as well as other tuners with a greater knowledge of how the system functions and what it can do. peace out,


_Modified by Coupe__88 at 2:19 AM 10-12-2003_


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## Guidofester (Aug 28, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Keep at it guys. Keep it real(Real VW that is).
Forgive me for previously stating that what you guys are doing is a waste of time. Oh contrair, I am intrigued by your efforts.
I am very pleased with the performance of my stock digi II set up However, I am interested in the digi I set up found on the G60. From what I have read on Vortex, S & S tuning can progam a chip for your specific application. Meaning that the chip would be tune for you specific application,Including cam P&P etc.. That's what I'm interested in learning more about. 
Correct me if I'm wrong but, The main difference in the Digi I and the Digi II is the use of a Map sensor versus a Maf. Is there any reason why we cannot use a map sensor instead of a Maf. That would eliminate the restriction.
I only mentioned the Digi I and Mega Squirt($200 system) because these systems seem to be the next option to consider, if considering boost. The chips can be taylored to meet your specific application. 
Anyway keep up the good work.


_Modified by Guidofester at 4:41 PM 10-13-2003_


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Guidofester)*

At first I was all over the Digi 1 idea. I was a little discouraged at the scarcity of Digi 1 parts and lack of an accurate swap list. I talked to mkrad and a few others about it and they all agreed that for a 2.0 with headwork and mild cam that Digi 2 would be good enough. If I were to get ahold of everything needed for under $200 then I would be stoked, but right now my friend is trying to chump me 200$ just for the ECU. 
til then.... digi 2 , cause 2 is better than 1














http://****************.com/smile/emthup.gif


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

update: I've found a combined adjustable FPR and power boost valve (adjustable fuel pressure AND rising rate fuelling) supplier (in the UK) - about $100, and they come in 'base' 2.5, 3.0 and 3.5bar flavours. Going to see how common they are and if I can source a secondhand one, if not i guess i'll have to stump up the dough. As soon as I've got the FPR it and the VAM are going to be bolted on and its off to the rolling road for setup and dyno run http://****************.com/smile/emthup.gif
It is possible to remap the digi II chips too (as you mentioned with digi I above) - syealth racing here in the UK does them , for one - custom burnt remap chips.
(Off topic for this thread, but I just finished modiyfying the TB etc I also have and now have all the parts I need for a 3" diameter path all the way from intake to manifold if I fit it all







Promise not to stick it all in until after the dyno







) 
Dan


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif you have a lot to look forward to my friend


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## Red Cab (Sep 3, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

The rising rate FPR would only be needed if you are going to fo FI. Normally aspirated engines don't need the rising rate. All fuel pressure regulators will increase fuel pressure based on manifold vacuum but the rising rate variety will increase fuel pressure in response to the manifold becoming pressureized (boost).
An intake usually operates under vacuum. Only under WOT does the manifold approach atmospheric pressure. The whole idea of the FPR is to maintain a constant pressure differential at the tip of the fuel injectors. That is the pressure difference between the pressure of the injector and the surrounding environment (manifold or injector port). That is why even a stock injector will have a variability (not adjustability) between closed throttle and WOT of about 1 BAR (14.5psi).


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Red Cab)*


_Quote, originally posted by *Red Cab* »_The rising rate FPR would only be needed if you are going to fo FI. Normally aspirated engines don't need the rising rate. All fuel pressure regulators will increase fuel pressure based on manifold vacuum but the rising rate variety will increase fuel pressure in response to the manifold becoming pressureized (boost).
An intake usually operates under vacuum. Only under WOT does the manifold approach atmospheric pressure. The whole idea of the FPR is to maintain a constant pressure differential at the tip of the fuel injectors. That is the pressure difference between the pressure of the injector and the surrounding environment (manifold or injector port). That is why even a stock injector will have a variability (not adjustability) between closed throttle and WOT of about 1 BAR (14.5psi).

Thanks for the info, Red Cab. I was interested in these mainly because they are among the cheaper adjustable FPRs I have found and seem to be relatively common (and therefore, I hope, easy to find secondhand). I have no intention of going FI, and the FPRs I was looking at show a digifant application, and make no mention of the necessity of a turbo appliction - I will make sure to check with the company that this is not simply a case of either myself or them getting confused over terminology http://****************.com/smile/emthup.gif 
As I understand it, a 3bar FPR keeps the fuel pressure at 3bar only at WOT (ie it is a maximum figure) and that the pressure at idle will be 0.5-1bar less?
Thanks for the excellent information as usual, anyway - I hope to not only have results at the end of this but (if there is a gain) all the info others need to achieve the same should they wish - part numbers, FPR pressures set to etc etc.
Thanks again Red Cab







And while I'm at it, a







to Brian for the help and thread-pimping


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*















for sure, I know a couple people have possibly tried or throught of the concept of the bigger VAM but Im giving credit to Daniel since he had the idea and sparked more ideas in my mind and also since he is actually following through with it. big ups to gearhead, red cab , mkrad, and others. 


_Modified by Coupe__88 at 9:12 PM 10-13-2003_


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## docspeed1 (Apr 26, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

This is perhaps the coolest, most useful thread I've ever seen on vortex! Good work by all involved. I had the idea of trying a BMW VAM a few years ago but couldn't find one at a reasonable price that I was sure would work properly. This is especially interesting to me because I am planning a turbo digi 2 with an EIC and as I see it, the VAM is still the biggest restriction that I was worried about. 
Dan, it would be interesting to dyno the car with a vacuum guage hooked up. If the vacuum at WOT (although minimal, it is still there) is significantly less with the bigger VAM, that would tell you for sure that with enough tuning, there is potential for more power.


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## docspeed1 (Apr 26, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

I was thinking tonight, and I think I may know why your car would not run when you tried the BMW meter. It would appear that the BMW part has a similar (if not identical) ohm vs flap position as the VW unit. I figure that at idle, the flap would need to be in the same position on the BMW VAM as the factory piece. Seeing as how the VW engine would be "pulling" less air than the much larger BMW engine at idle, I propose that the spring tension would need to be backed off significantly. This would contribute to a lean condition, but the adjustable FPR should be able to cure that. What do you all think of this theory? It is just theory, but it makes sense in my twisted head


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## Johnson (Apr 29, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (docspeed1)*

sorry if this is off topic or not even close to being usable but i know fords use the VAM`s in the turbo cars there is usually very good tech info on http://www.turboford.org maybe do a search or post a question
and i found this site 
http://www.merkurencyclopedia.....html
maybe worth a look 
hope some of this helps, sorry if it dosent ...


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Johnson)*

thanks for the good insights definiatly something to spark more ideas. Im gonna do some random tests on my own car tomorrow with a spare digi vam opened up to meter and modulate by hand. daniel , might you need to adjust the idle screw and CO screws to get it to idle? im gonna try to open the flap more (simulating more air) and try to start it and mess with stuff.)


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (docspeed1)*

Thanks for the ideas http://****************.com/smile/emthup.gif APologies if the BMW VAM idea has temporarily hijacked this thread aswell! 

_Quote, originally posted by *docspeed1* »_I was thinking tonight, and I think I may know why your car would not run when you tried the BMW meter ...Seeing as how the VW engine would be "pulling" less air than the much larger BMW engine at idle, I propose that the spring tension would need to be backed off significantly. 

What you say is probably true - I would need make sure the heavier flap didnt choke the life out of the engine - I will compare the flap tension when I have them both out of the car - this was the "hoover idea" we had further up the page - to try and get the BMW VAM acting as close as possible to the digi2. Its definitely going to be a consideration tho - thanks.

_Quote, originally posted by *Coupe__88* »_daniel , might you need to adjust the idle screw and CO screws to get it to idle? im gonna try to open the flap more (simulating more air) and try to start it and mess with stuff.) 

If I took the idle screw out a bit it certainly might help get the car started with the BMW VAM at stock spring tension for the moment, but I don't think its a long-term solution to idle at 2k rpm







As for the CO screw, I've never actually messed with it - when I do fit the FPR and VAM, rest assured I will mess with absolutely everything I can think of to get the thing up and running. With the adjustable FPR, there should be enough factors that I can tweak to get it up and running.
Again, thanks for the ideas, I'll soon post up some questions if I really can't get it working. http://****************.com/smile/emthup.gif
Dan


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## docspeed1 (Apr 26, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*


_Quote, originally posted by *DanielAdams* »_
What you say is probably true - I would need make sure the heavier flap didnt choke the life out of the engine - I will compare the flap tension when I have them both out of the car - this was the "hoover idea" we had further up the page - to try and get the BMW VAM acting as close as possible to the digi2. Its definitely going to be a consideration tho - thanks.


Well, thats close to what I had in mind, but not exactly. I wasn't thinking so much about the weight of the flap, but that at any given flap position, the BMW VAM would flow more air due to its larger size. Since the engine would draw the same air at idle with either meter, I think the BMW VAM would need to be loosened off so that it gave the proper "idle speed" ohm reading the the ECU. In fact, I think to work properly, it would need to move proportionally the same as the VW unit for any given load/throttle setting. The higher pressure FPR will only be truly meaningful if you are giving proper inputs to the ECU.
This is a great thread, lets keep it going until we actually figure out this much misunderstood system. I have had 3 cars with digi2. I think its a great system if cared for and maintained. It would sure be nice if we could figure out how to make it more useful for performance applications.










_Modified by docspeed1 at 7:07 AM 10-14-2003_


----------



## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (docspeed1)*

This is sort of off topic but an idea sprouted so im going to tell and if you dont like it then TOO FRIGGIN BAD!!!
..
pardon...
anyhow 
I have an idea on how to get the Motronic 2.9 (ABA 2.0) MAF to work. 
the MAF uses a voltage signal right, VAM uses a resistance signal right?
SO. you would need an ammeter to measure the current flowing through the MAF 
wires. since V/I=R Voltage over Current equalss resistance the sensor would produce the voltage signal , divide with the measured current and the quotient would be an appropriate resistance signal.
This is under the assumption that the ECU doesnt have parameters to the VAM values, but will react with any given resistance value. 
I have a good feeling about the BMW VAM , I just had this idea and maybe someone with more knowledge of electronics ( heck, im barely 18 i dont know anything yet







) might ponder this and maybe spark some other ideas.
expensive to make? possibly complicated? possibly, its just more for our brains to snack on. cant stop thinking until something is proven to work...... off to experiment.


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

i did some tests. Now I think I know why the VAM uses set integer resistance signals (see Daniels graphs above) instead of infinite resistance values ( for example, the VAM potentiometer gives a 600 ohm signal for a varying distance of travel , it is an approximated value and the needle could move a few millimeters in one direction but would still give a 600 ohm reading as opposed to giving an exact reading such as 623.51 ohms) I believe the reason behind this the constant variation in movement of the flap from the intake valves opening and closing. 
which if the VAM gave an exact value, would cause sudden changes in injector duration and may be limited by slow signals therefore causing inaccuracy in fuel mixture. second. the VAM needle position is influenced by bumps and gravity (if mounted on a slant etc, not very much but its still there) which would also cause innacurate mixtures. From this I believe that the oxygen sensor circuit is highly depended on to take these approximated VAM signals and fine tune them. This might be why the O2 sensor is such a sensitive and crucial part for performance on these cars .
While at Idle the VAM needle seemed to stay between the 1st and 2nd contact on the meter ( Rest, 1 * 2, 3 etc) 
but again, this air meter might not be calibrated correctly.
note: im running a stock 1.8 block , stock head, 266 TT cam, k&n filter and dual outlet manifold which influences incoming air more than a completely stock setup. 
tensioning the VAM spring significantly closes the flap and wont allow it to idle 
loosening it significantly lets it open too much and wont allow it to idle
And I was very surprised that the VAM flap didnt get pinned open , when given full throttle the flap would open up significantly but not all the way and it would keep opening ever so slightly towards OPEN with the increasing engine speed
i should have spent more time watching and waiting for it to pin open and at what point etc.. 



_Modified by Coupe__88 at 9:16 PM 10-14-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Hi Brian, great posts as usual. I'm not going to try and post on the ABA MAF idea because, whilse it sounds like a good idea, its technically a bit out of my league!

_Quote, originally posted by *Coupe__88* »_i did some tests. Now I think I know why the VAM uses set integer resistance signals.... I believe the reason behind this the constant variation in movement of the flap from the intake valves opening and closing. 


It could be, but I'm not sure - there is a second 'dampening' flap at 90deg to the airflow flap, wihch is meant to dampen out this kind of fluctutation, and secondly the flap could just as easily cause the needle to skip between two of the preset points, rather than within the range of one of them - if you look at the graph, weknow the 'peak' is about where it idles, but the resistance doesnt really fall off too sharply until the flap must be almost fully open - the resistance curve is quite 'flat'. This makes me think that the VAM reading is not actually *that* important - I would love to see the lookup tables etc but I expect that others factors such as RPM have a greater small-scale difference on fuelling, whilst the VAM makes a less subtle effect on fuelling - a 'little' at idle, 'some' at mid-open and 'lots' at or leading up to fully open. Pure speculation unless we can find out the ECU fuelling lookup tables.

_Quote, originally posted by *Coupe__88* »_i From this I believe that the oxygen sensor circuit is highly depended on to take these approximated VAM signals and fine tune them. This might be why the O2 sensor is such a sensitive and crucial part for performance on these cars .

It could be, but I'm not so sure - my digi2 (european) has no o2 sensor or cat and, by all accounts, is more powerful and runs with less hesitation than a US digi2. I would say that the o2 sensor is more emissions-related, and if anything leans out the mixture more to stop the cat from being destroyed. I honestly dont believe now that the VAM makes particularly subtle second-to-second fuelling adjustments as I used to imagine - I think digifant 'lag' off idle, as well as the real-world issue of the flap 'bouncing' point towards the designers being forced to make the VAM have quite a crude effect on fuelling.


_Quote, originally posted by *Coupe__88* »_itensioning the VAM spring significantly closes the flap and wont allow it to idle 
loosening it significantly lets it open too much and wont allow it to idle


Thanks, thats useful information - I'll definitely have to bear this in mind if the BMW VAM causes problems with idle, dying etc.

_Quote, originally posted by *Coupe__88* »_i
And I was very surprised that the VAM flap didnt get pinned open , when given full throttle the flap would open up significantly but not all the way and it would keep opening ever so slightly towards OPEN with the increasing engine speed


I guess that shouldnt be too surprising - the wider the flap opens, the greater the pressure the spring is exerting back on it against the airflow, so the harder it is to open it the final few mms. However, you would have thought that they would calibrate it such that full load was pinning the VAM open. This was running your car in neutral I suppose on yor driveway? Perhaps the fact that your car was not under actual load meant it required less air than under real driving conditions?
quick update of my own aswell - dont expect any results too soon, I can't find a secondhand adjustable FPR at the moment and the new ones I can find are either silly money or out of stock on backorder.
Great work, anyway http://****************.com/smile/emthup.gif 
Dan


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

im going to call around on some BMW air meters and adjustable FPRs, I dont expect to be buying an FPR (poor college student syndrome) but if i can finr a VAM for under 50, i will hit it up and get workin on this more.


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## docspeed1 (Apr 26, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

I've been watching some on ebay. I think I'm going to buy one too. They seem to be going for about 25-50 bones. Several to be had. Not bad for the potential they may have.


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (docspeed1)*

did you ever hear that song by the Kottonmouth Kings that goes... "BUMP, BUMP BUMP"


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

Just some random thoughts/ & a bump to keep this going
So Daniel does the car start/run with the BMW air meter?
I wonder if it's possible to dyno the car with a cone filter in place of the airflow sensor. Manipulate the AFM door to keep the car running & just dyno the car with the door wide open, to see just how much of a restriction the stock meter actually is. (this would take two people)
Many of you complain about how your Digi2's run lean. The AMS Chip fixes most the problems with Digifant 2.
My car runs around 13.2:1 at WOT & about 14:1 around town cruising(open loop)
Personally I've found that their is not enough fuel pressure to my injectors with the stock 3bar fpr. The fuel rail runs dry. (runs out of fuel in 5th gear)
The AMS Chip ignores coolant temp sensor values. The stock chip retards ignition timing when it senses hot coolant temps.
AMS fixes off idle hesistation, completely.
AMS raises the rev limiter to 7,000rpm & removes speed governor.
AMS Chip has more aggressive timing & fueling maps.
The only thing it hasn't fixed is the Digi-lag which can be minimized with more fuel pressure. 
The one gripe about this chip is that their is no ignition retard in startup mode. So it cranks slow upon startup.


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

just for fun 535 VAM new is $349USD 
thats almost as much as my car cost


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## docspeed1 (Apr 26, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Just came across this on the SDS website:
"On engines originally equipped with Bosch L- Jetronic systems with door type airflow meters, there is a microswitch in the airflow meter used to control the fuel pump. If the meter or wiring harness is removed, you will have to rewire the pump to another power source." 
Daniel, maybe this is a difference that needs to be adressed? When you tried to start your car are you sure that the fuel pump was running? Just curious as to if and how the VW and BMW parts may or may not be different in this respect?


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (docspeed1)*

I thought the Hall sender sent an RPM signal to run the fuel pump . i will experiment


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (docspeed1)*


_Quote, originally posted by *Digiracer* »_ So Daniel does the car start/run with the BMW air meter?

I haven't fit it yet - I'm waiting until I have the FPR here so I can throw everything on at the same time as I get it set up and dynoed at the rolling road - FPR could now be another 1-2 weeks away, I cannot find a cheap (or secondhand) in-stock adjustable FPR. I am searching tho and will definitely post updates as and when they happen.

_Quote, originally posted by *Digiracer* »_I wonder if it's possible to dyno the car with a cone filter in place of the airflow sensor. Manipulate the AFM door to keep the car running & just dyno the car with the door wide open, to see just how much of a restriction the stock meter actually is. (this would take two people)

that's not a bad idea at all, as long as you kept an eye on the gas analyser and made sure not to have a mismatch between metered 'flow' and actual flow and leaned it out, this should give us a good idea of the restriction the VAM causes. As I say, tho, I'm going to spend my dyno money just the once - when I get te VAm and FPR fitted. I've not got handfuls of money to throw at this project - I only finished my MSc last year and have been struggling to get a permanent job since (IT, market sucks at the moment) so everything is strictly ghetto-budget









_Quote, originally posted by *Digiracer* »_Personally I've found that their is not enough fuel pressure to my injectors with the stock 3bar fpr. The fuel rail runs dry. (runs out of fuel in 5th gear)

I hadnt realised that, but it may explain why mine runs lean even with the (non-AMS) chip in place. Makes me think my FPR money is well placed, so thats releived a bit of purchase anxiety









_Quote, originally posted by *docspeed1* »_Just came across this on the SDS website:
"On engines originally equipped with Bosch L- Jetronic systems with door type airflow meters, there is a microswitch in the airflow meter used to control the fuel pump. If the meter or wiring harness is removed, you will have to rewire the pump to another power source." 
Daniel, maybe this is a difference that needs to be adressed? When you tried to start your car are you sure that the fuel pump was running? Just curious as to if and how the VW and BMW parts may or may not be different in this respect?

Thats a good point - at the time, I didnt put too much energy into trying to figure out why it wouldnt start, but its a plausible reason - however, two things make me think it probably wasnt this - firstly, the 4-pin plug on the BMW VAM is the same as the 4-pin plug on the VAG VAM, and I saw no other micrswitches anywhere on the BMW VAM or the car I removed it from. Secondly, I have a semi-stripped interior and I can hear just about everything that goes on in my car - I hear the fuel pump clunk into action when starting my car and I'm sure I would have notivced the relative silence if it hadnt whirred into life. I'll make sure to lsiten out for this when i next try it, tho.

_Quote, originally posted by *Coupe__88* »_just for fun 535 VAM new is $349USD 
thats almost as much as my car cost

LOL, yep me too - the equivalent of about $400 mine cost when I got it. Definitely a fixer-upper.








Dan


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## B3VR6 (Jan 4, 2000)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*


_Quote, originally posted by *Coupe__88* »_
I have an idea on how to get the Motronic 2.9 (ABA 2.0) MAF to work. 
the MAF uses a voltage signal right, VAM uses a resistance signal right?
SO. you would need an ammeter to measure the current flowing through the MAF 
wires. since V/I=R Voltage over Current equalss resistance the sensor would produce the voltage signal , divide with the measured current and the quotient would be an appropriate resistance signal.


I have a basic stamp computer that's been collecting dust for a while. It also has a serial LCD display that I was toying with the idea of setting up as a digital gauge panel for oil pressure, temperature, etc.
I know the newer basic stamps are very fast and rugged. It would be not too big of a programming project to set up a basic stamp to read the resistance of a sensor input and output a voltage... or vice-versa. You could even set up an additional input to look for if the car was pumping NOS and add more fuel, or any other thing we could dream up.
Basic stamps:
http://www.parallax.com/html_p...s.asp
The best BS2 can process at 12,000 instructions per second.. faster than anything we'll need.


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## B3VR6 (Jan 4, 2000)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*


_Quote, originally posted by *Digiracer* »_J
The AMS Chip ignores coolant temp sensor values. The stock chip retards ignition timing when it senses hot coolant temps.
AMS fixes off idle hesistation, completely.
AMS raises the rev limiter to 7,000rpm & removes speed governor.
AMS Chip has more aggressive timing & fueling maps.
The only thing it hasn't fixed is the Digi-lag which can be minimized with more fuel pressure. 
The one gripe about this chip is that their is no ignition retard in startup mode. So it cranks slow upon startup.


Thank you Digiracer! You've just explained a few of the things I've been wondering about with my car. My AMS chip is custom for the Cam and exhaust I have installed. My head has been P&P'd and shaved enough to now be an interference motor.
My car is a pain in the butt to start when it's cold out. It cranks over once and stops. I usually either have to give it gas or just try again where it starts right up.


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## darksideofthemn (Feb 2, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

Nice guys! I can't wait to see what the final outcome is. I'm sure you'll pull something off cause anything is possible with some effort and you guys seem to be putting plenty of that in. http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Bump Bump, I really hope this works. Otherwise I need to go standalone.
I've been working on a project that should make some good power.
I have a worked p&p Crossflow Head converted to solid lifters, w/ WEB Springs & a WEB 280 solid cam, & stainless valves, decked for 10.44:1. 
It'll inhale through a custom short runner, log style intake w/ velocity stacks on each runner w/ a obd1 VR6 T-body. The previous owner said the head will pull up to 7,500 rpm w/ SDS in his Scirrocco.








One way or another I have to ditch this f#%$ing stock air meter.


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Bump I don't want this thread to fade away.
any updates anyone?


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

My attention is on my work and studies for now, I wish i had the cashflow to hit up an adjustable FPR. I wasnt about to let this thread die off. rather let it sleep until something good came


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

I have this thread bookmarked and I check back every so often. My adjustable FPR is on the way finally. When it gets here, my serious VAM-meddling will begin in earnest, but this is just one among a few projects I am carrying out on my car at the moment and, like Brian, I do have an ex-Vortex life to attend to aswell








If the FPR arrives before this weekend, then saturday will see resutls of one sort or another, but I wouldnt hold your breath. Patience, my son








Dan


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## d-c (Jun 5, 2003)

digi 2 newbie question.. which way do i turn the adjustment on top the maf to get it to lean out???


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## Coupe__88 (Sep 14, 2003)

*Re: (d-c)*

digi 2 oldbie answer.. that screw is for the CO adjustment, all fuel mixtures are computer controlled by injector duration. 
In my experiences this week , the screw did absolutely nothing. 
Daniel:  props on ordering the FPR, where did you get it, how much was it, and does it bolt up to the fuel rail or does it tap into the fuel line? 
I think we are all anticipating the outcome of this. keep it real.


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## darksideofthemn (Feb 2, 2003)

*Re: (Coupe__88)*

Hey guys you might be able to get some info from the guy at this link if he figures things out. 
http://forums.vwvortex.com/zerothread?id=1078105 
If his thing can read chips he could find out what the computer is doing with the info. I'm not sure it can read the but at least he would be able to burn an identical chip that would understand the higher figures. since he has no idea what he has really maybe he would sell it to one of you guys. I also know a guy that used to be able to program eproms and i will run this by him. He might be able to do something with this machine. At worst it could be made into a simple upgrade kit with the sensor and chip. Over head cost wouldn't be bad and it would be able to help us fight those 16v guys and their high redlines.


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## DanielAdams (Aug 22, 2002)

*Re: (Coupe__88)*

Hi all
I got the adjustable FPR from Demon Tweeks. By foregoing the more agressive rising rate fuelling of the power boost valve and sticking with a straight adjustable power boost vavle with factory fuelling curve based on manifold vacuum, I got it for 40 UKP rather than 100 UKP.
It is 3.0-4.0 bar adjustable (tho they strongly advise not going over 3.5 bar on street car) and fits to the factory rail with stock fittings.
I'm not sure that the adjustment is particularly subtle, being just a small screw on top of the FPR, but that's what you get for trying to save money








Dan


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## set_au (Oct 24, 2003)

*Another alternative*

I don't really like the idea of fighting with the black box design of the Digifant. Upping the flow of the VAM and boosting the fuel pressure may solve the fuel and air availability issues but its complexity is bound to introduce other limitations
For cheapness and simplicity how about hooking an air flow sensor with a nice linear output to an analogue PWM (555 timer for example) which drives the injectors directly? It would be basically like a carburettor then - completely open loop, and you could adjust the mixture with a potentiometer. Of course you could make something more complex, but this should work for a start.The Digifant unit could be kept to drive the idle stabiliser and ignition timing functionality only.
Another alternative might be to make the VAM a little leaky so that at full throttle at maximum engine speed 33% of the air comes in after the throttle body (for a 50% increase in total air flow potential). 
The leaky path would need a spring loaded vane too to share the flow in proportion, but no sensor - you could build it yourself.
I bought a differential pressure sensor today so I will see if the VAM is indeed a problem once and for all.


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## DanielAdams (Aug 22, 2002)

*Re: Another alternative (set_au)*

Some interesting ideas there, mate. Great to see a few more people getting stuck into this. Not bad for a first post! This is becoming a right international thread, this is








With your idea about letting air in after the throttle body tho, I'm a bit confused as to how you would proposed doing this - having effectively a second VAM (albeit with no electonic outputs) as a load-dependent air inlet? Sounds kind of wacky and I think it'd take more than just throwing a few peices together to get it running so it idles right etc. Still, what do I know








I'd be really interested to see the results of the pressure differential tests - well done for taking this forward another step http://****************.com/smile/emthup.gif 
Dan


_Modified by DanielAdams at 9:10 AM 10-24-2003_


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

bump


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## ONLY 8V (Mar 4, 1999)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

Just to throw my 2 cents in. The stock air meter for Digi2 is good for 177 normally asperated crank hp...this according to bosch (looking at the area of its opening). If look at the area of the throttle body openings minus the width of the butterfly holders you will see that is is just about the same area as the AFM opening. IMO you are better off spending money on other option to improve your performance if you are under the 177 hp mark. With the stock AFM and fueling + the AMS chip (on top of a pretty build N/A 1984cc 8V street motor that passed CA smog) I was able to pull 14.8s in the 1/4 with full interior and radial tires. The thing to keep in mind with 8V's is that HP is in the head, cam, cam timing, and displacement....if you have a properly functioning DigiII system you should be more than fine for anything on the street.
Jason


_Modified by ONLY 8V at 4:30 PM 11-3-2003_


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## docspeed1 (Apr 26, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (ONLY 8V)*

Well, I've been hanging out in the 16v forum, cause I just bought a 90 GTX. I was surprised to find out that a lot of guys are converting to digi2 on their 16v's because it is so much simpler than cis-e or cis-motronic. If this whole idea pans out it would especially benefit a 16v engine imo.


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (ONLY 8V)*


_Quote, originally posted by *ONLY 8V* »_The stock air meter for Digi2 is good for 177 normally asperated crank hp...this according to bosch (looking at the area of its opening).

That seems like an awfully precise figure - how exactly did you figure that out or find that figure?
On the other hand, that would explain a lot, for me at least - my dyno plot clearly showed my engine peaked at 176 crank hp after my torque curve really flattened out aboe 5250rpm - others have found similar results - so this might indicate that ant or all of the MAF options discussed in this thread could really open up the hp potential of digi2s - which is exactly what we were hoping.
Seems like almost *too* coincidentally accurate a figure








Dan


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

Yeah Dan , I think he's in on some secret covert operation .... oh wait, were only talkin bout dubs here. bumpity bumpity, ahh crap, my teachers gettin mad at me


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## DanielAdams (Aug 22, 2002)

*Re: Another alternative (set_au)*


_Quote, originally posted by *set_au* »_I bought a differential pressure sensor today so I will see if the VAM is indeed a problem once and for all.

Did you ever run those tests? Would be interesting to see if this backs up some of the other information that has been posted since http://****************.com/smile/emthup.gif 
Dan
P.S. Brian, shaddap!










_Modified by DanielAdams at 4:03 PM 11-5-2003_


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## ONLY 8V (Mar 4, 1999)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*


_Quote, originally posted by *DanielAdams* »_
That seems like an awfully precise figure - how exactly did you figure that out or find that figure?
On the other hand, that would explain a lot, for me at least - my dyno plot clearly showed my engine peaked at 176 crank hp after my torque curve really flattened out aboe 5250rpm - others have found similar results - so this might indicate that ant or all of the MAF options discussed in this thread could really open up the hp potential of digi2s - which is exactly what we were hoping.
Seems like almost *too* coincidentally accurate a figure








Dan

Of course its a precise figure as its based off a mathmatical formula. I don't have the math in front of me right now, but I'll dig it up tonight when I get home. Because this is a mathmatical figure I should have worded my statement that the 177 N/Aed crank hp was the theoretical limit.....though from what you stated this looks dead nuts. I agree that a larger AFM may unlock something over say 175 hp, but you'll also need a larger throttlebody to yield anything significant (probably larger intake runners and valves as well - 42x35mm...and a real nice 4-1 header with oversized primaries). On the same note, and assuming normal asperation your motor will also need to spin the rpms (probabaly making hp at or greater than the 8K mark) to be able to handle the additional air & gas without going to something larger than 1984 - 2032cc. So this means that you'll need to make conciderable effort to lighten and balance your motor & head to allow it spin those numbers.
I'm curious, your crank dyno numbers....are those from a real engine dyno (motor out of car dyno reading HP at the crack) or on a rolling dyno (hp taken at the wheel and then est crank hp thru math)?
Jason
_Modified by ONLY 8V at 8:59 AM 11-5-2003_


_Modified by ONLY 8V at 9:07 AM 11-5-2003_


----------



## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (ONLY 8V)*


_Quote, originally posted by *ONLY 8V* »_
Of course its a precise figure as its based off a mathmatical formula. 


OK, right - I wasn't sure if you had calculated it yourself of found some figures in a book or article.

_Quote, originally posted by *ONLY 8V* »_you'll also need a larger throttlebody... probably larger intake runners and valves as well - 42x35mm...and a real nice 4-1 header... something larger than 1984 - 2032cc.

My own engine has all that goodness, but are you saying that on a stock or mildly modded motor you would fall into the "won't do a thing" camp?

_Quote, originally posted by *ONLY 8V* »_
I'm curious, your crank dyno numbers....are those from a real engine dyno (motor out of car dyno reading HP at the crack) or on a rolling dyno (hp taken at the wheel and then est crank hp thru math)?

The latter, like most people I don't have the time, money or access to equipment to be hooking the engine up to an engie dyno.
Dan


----------



## ONLY 8V (Mar 4, 1999)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*


_Quote, originally posted by *DanielAdams* »_
My own engine has all that goodness, but are you saying that on a stock or mildly modded motor you would fall into the "won't do a thing" camp?


Sorta....I wouldn't call a N/A'ed 8V motor making 175 hp mildly modified...I'd say you have some pretty significant work done to be making those numbers. A normally asperated 8V motor making much more than 175 hp is borderlining whether it'd be suitable for the street any longer....if your goal is a pure race car then I say go for it, but then I'd question why you're not going with carbs or ITB fuel injection. 
The point I was trying to make was that for 95% of the people that just want a fast streetable car, focusing on a larger AFM just doesn't make sense for the monetary investment and the tuning headache...money is better off spent in other places that will yield greater hp. With that, I would recomend that if your car isn't making at least 170-175hp (backed-up by actual dyno numbers) then don't bother with this, the stock AFM will suit you just fine. 
Thanks for helping me clarify!
Jason



_Modified by ONLY 8V at 9:34 AM 11-5-2003_


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## darksideofthemn (Feb 2, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (ONLY 8V)*

don't let this die bump


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (darksideofthemn)*

UPDATE: FPR has arrived ad will be fitted as soon as. Once that's fitted and I'm satisfied its working and adjustable as required, I'll be fitting the VAM so stay tuned.... nothing ever happens quite as quick as you like it tho, so we're probably talking weeks rather than days before I can give you a dyno comparison, to be realistic...
Dan


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

Dan, we may have thought telepathetically or whatever today, cause earlier today I was going to ask you if you had gotten it








Anywho I want to see how the bad boy fits... on the rail.. or in the fuel line ,
glad to hear your crazy postal system works.


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Its been a while, I forgot, what are we doing again?


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

just if anyone is curious, The G60 FPR and stock Digi2 FPR are the same so I guess an Adjustable FPR is gonna be the way to go for me, along with corrado injectors. I cant source a VAM in my area, time to start looking around more 
B...... 
..U....
....M..
......P


_Modified by Coupe__88 at 9:04 PM 11-22-2003_


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

since Brian is bizzumping away anyway....
I have sourced an o2 sensor (not stock on euro digis) and an air-fuel meter so that I can keep track of air-fuel ratio after fitting the VAM and FPR. air-fuel gauge will be fitted tomorrow (sunday) morning, and the o2 sensor I will have fitted monday morning hopefully (its going to be a 'drill a hole in the exhaust and weld a nut on' job), then the FPR probably the day after that (tuesday).
Dyno and VAM will happen at the same time as soon after that as I've got enough money to afford it. Could be days, could be weeks. Still waiting to hear back on 2 job applications so wish me luck








Its embarassing how long this is taking to sort after getting the VAM but I want to do it right. Any of you US lot got an explanation or pic for *exactly* where the o2 sensor fits in the factory location?
Cheers
Dan
PS When I do finally get everything sorted, I promise lots of photos and dyno shots to make up for it


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

On the dual outlet manifold cars with cat converter, the O2 is about an inch or more in front of the cat sticking out on the right side of the car , you will be safe as long as you mount it within a union where gases from all 4 cyl. can pass by the sensor


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## darksideofthemn (Feb 2, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

bump


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## RavenGTi (Dec 12, 2000)

most dyno figures i have seen from across the pond seem higher than they should. if i recall correctly, there are two types of HP, kinda like standard and metric. i think it is measured differently over there. 
it also might be because they are given a calculated crank figure from the original wheel figure. here is a link from puma racing about how inaccurate calculated flywheel figures are : http://www.pumaracing.co.uk/setup01.htm 


_Modified by RavenGTi at 7:12 PM 12-14-2003_


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## Slow1.8 (Oct 9, 2003)

*Re: (RavenGTi)*

I'm just talking out my ass but. 
Can you put the FI from a honda in a vw? I don't even know what sytem it has but theres no nothin infornt of the T/B. You know what I'm talking about?


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## Coupe__88 (Sep 14, 2003)

*Re: (Slow1.8)*

I would assume it would as long as the injectors fire all at the same time instead of individually and the distributor is mechanical and not 100% computer controlled


_Modified by Coupe__88 at 7:49 PM 12-14-2003_


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## B3VR6 (Jan 4, 2000)

Coupe... why would you place that restriction on it? If you're moving the entire FI system over, who cares if it's gang-fired (like DIGI II) or Sequential or if it has a distributor or is distributorless?
The only hitch I could see is if it was distributorless, we'd have to figure out a way to retrofit a camshaft or crank position sensor.


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## Coupe__88 (Sep 14, 2003)

*Re: (B3VR6)*

eh, he was wondering if a honda EFI would work on the car. I was just giving some insight, definiatly not what I would do. If nothing else, Megasquirt


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## pfcs1 (Jun 7, 2003)

I've been following this thread with interest.
I'm running an SCCA ITB (class, not throtBdy) Golf w/digifant II and have been trying to deal w/digi. Here's some helpful info for you guys. With allowed mods in this application, engine output is raised by 10-15%, mostly by headers, valvework, etc. Even with this modest improvement, and with +5psi fuel, stock chip goes lean @ top end (if 12.5/1 @ 4500, is 14/1 @6000) AMS 2.0 is very rich overall, and requires lower (-10psi) overall fuel pressure but is now very rich above +/- 5300, ie: if 12.5 @4500, is 10.0/1 @6500.
AMS rev limit is 6700rpm.
you can't make sense of anything if you run an oxygen sensor-it will skew any obsevations when it's active (ie: full throttle switch opened, coolant temp warm). Its fine to run it once the system's set up properly.
a rising rate regulator is one that raises the fuel pressure in response to manifold absolute pressure (in NA apps, "vacuum"). The stock (and allmost all others I'm aware of) Digi regulator is one to one(1/1), it raises the fuel pressure by the same amount the pressure (absolute pressure-a perfect vacuum is 0 absolute pressure) in the manifold changes. The stock rgl is a 3bar (45psi) rgl. 
I run a 1/1 adjustable rgl in my car.
a 2/1 regulator would raise the pressure by 2 bar @atmospheric (full trottle) pressure signal. This was the hot setup for the old "D" Jet system when making big airflow improvements, and possibly it or a 1.5/1 rgl would be good with big mods. Unfortunately, due to class restrictions, its not an option for me!
some thoughts regarding larger VAM: 
I had thought that by 4000 or so the VAM would be fully opened (I think thats the case with L Jet, @which point fueling is determined by an RPM map in the ECU). That is not the case in my app. Probably with much modified engines, it becomes a big issue. I,ve been datalogging RPM, A/F ratio, and VAM load signal volts. The load signal rises in a very linear way from 4000 to 6500, reaching a max of 4.4V (5v reference signal) and having the same slope as the rpm plot.
to compare BMW VAM to VW, (in stock app context) you need the ECU to see the same values/load/rpm. I imagine that if you measure the load signal at idle, then check it on the BMW VAM and soften the spring til it matches stock, youd be in the ballpark. Obviously the bigger VAM from a bigger motor is meant to measure the much greater airflow of the BMW motor. The attractive thing about using this meter is the possibility of having a larger port and a softer sprung vane, thus eliminating the (assumed!) restriction to airflow of the stock VAM (would someone please put one on an airflow bench and answer this question before we put too much into this?) 
Assuming you get this working (hint-run a wire into cockpit from VAM load signal terminal to DVM-check V @full load/6000rpm and at idle. Try to adjust BMW spring to get same values-and ps: the idle airscrew in the VAM DOES DO
something- I'd suggest closing both before trying this [then you can open them up and see what happens to V] If this works, you've eliminated the restrictive effects of the stock VAM-great for you! You'll still be left with the high end lean out from the ECU which can be band-aided with raised fuel pressure only if you don't mind running rich as hell @lower rpm or loads-UNACCEPTABLE! Or there's the AMS chip-uniformly over-rich and dreadfully rich @high RPM (at least the rev limit's gone!) Whats needed is the ability to re-write the fuel chip. I have a chip reader/burner; I have a test bench that I can simulate all conditions and measure resultant Ms injector pulsewith; I have 4 channel datalogging in racecar to positively confirm results.
Is anyone out there able to write Digi II code?
Sam- put your money where your mouth is-don't blow smoke about "if someone came to Atlanta" or "we have it in UK but not here because no one wants to" (while at the same time saying that $250 to AMS is too much) I'm pretty convinced that Mark Collegin (AMS) is the only person in the world who's spent the time to decode Digi II and that he can't be bothered to play with it any more beyond recepies he made years ago-he's moved on to bigger things. Phil Hunt, Phil's Foreign Car, Kenvil N.J.


----------



## B3VR6 (Jan 4, 2000)

*Re: (pfcs1)*

Nice long post *pfcs1*! It's nice to see someone who has been pushing the limits in a race environment.
With regards to the AMS chip... I have one and I'm having the opposite issues. I am leaning out at high load/high RPM, but my head is shaved and I'm running a semi-hot cam with headwork. I have enough of a shave to make it an interference motor now... so I think that's the issue with my pinging.
I actually want MORE fueling even with the AMS chip because when I run a slightly advanced (1-2º) base ignition timing, the car pulls noticeably harder from 4k to redline... unless it pings. I had to go back to stock (6º BTDC) to get it to NOT ping during normal driving and it even managed to ping sometimes. I definitely don't want to have to back off on ignition timing any, so raising the fuel pressure via a different FPR seems for me to be the way to go.
Where did you get your FPR and for how much?


----------



## pfcs1 (Jun 7, 2003)

*Re: (pfcs1)*

completing incomplete/unclear things: 
regarding rising rate regulators: 1/1 (stock) digi regulator varies its 3bar (45psi) max pressure by 1 bar if presented with perfect vacuum @vacuum port: perfect vacuum (0psi absolute) yields 30psi fuel press; wide open throttle/no manifold vacuum(14.7psi/1bar [atmospheric pressure] yields 45psi.
3bar 2/1 regulator: 15psi @perfect vacuum; 45psi @ open throttle.
4bar 2/1 regulator: 30psi @perfect vacuum; 60psi @ open throttle.
This is a great tuning aid if you need to get more fuel at higher airflows without tuning the ECU. Changing the operating pressure of the regulator makes a linear (across the range) change in mixture, while changing the ratio of the regulator changes the slope of the fuel curve, making it richer at the top end.
re: stock VAM w/much mods- its a problem because the load signal goes "over the top" or even the meter gets fully open when a modded engine flows too much air. By over the top, I'm referring to the negative slope part of the resistance curve previosly posted.
I've checked and the load signal is majorly responsible for fueling decisions from ECU top end-the difference between 4.0v and [email protected] is about 10% @injector.
To get a big VAM working is a great idea and helpful-and only really useful if you can manipulate the fueling in the CHIP. If these 2 problems are solved then you have a very cheap/fairly high performing system-truly GREAT.
re: MAP sensor (G60) system- Sam: are you listening?
No problem to substiute MAP sensor signal for Vam signal except that ECU needs total chip rewrite because although electrically the signals are the same, their values have very different meanings. One measures airflow, the other manifold pressure (absolute pressure), so when you floor the throttle off idle, you get a high MAP value all the way to redline; with a VAM you get a modest increase in signal that grows steadily as engine acellerates-very different signals. If someone could re-write code for this mod (Sam?) G60 ECUS might come down a little in value (yes Sam-I know the dig I is ultimately superior) but this would be a great option for the less fortunate-and would open a huge market by my calculus.


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## pfcs1 (Jun 7, 2003)

*Re: (pfcs1)*

I cut up a stock regulator to make up a base to make an exit nipple from the fuel rail so I could outboard the regulator. Then I cut the top bell off a Volvo 960 regulator (because it has hose nipples on it and a co-axial mounting nut around the return nipple that make mounting easy). I got a piece of tubing (probably 1.5"/.120"wall, maybe 1.75") that fits over the reg body where the vacuum end was cut off. I welded a piece fo sheet metal across on end to seal it. I drilled a hole in the middle of the sheet metal for an adjusting screw, where i welded a nut for screw. (I got fancy here and counterbored/brazed washer to retain an "O" ring for vacuum seal-probably unneccesary) I brazed a little nipple into top to send vacuum to rgl; I welded 2 3/8" nuts 180* aprt to tubing near adjustment/closed end. I bent some 1/4" rod into a "U" that fits around the lower (pressure) chamber of rgl and welded 2 6mm bolts to it, long enough to reach thru the 3/8" nuts when the tubing seats against crimped bell of rgl. Find an "O" ring that is happy sitting around the neck of the bell at end of crimp. square the end of the tubing nicely and assemble using 2 m6 stopnuts and washers. I mounted it down low on pass strut tower and coupled it to a 3/16" brakeline tubing running thru firewall to adj knob and have press guage in cockpit. Running in conjunction w/ wideband A/F meter, (and datalogging on Palm Pilot) its so easy to identify results.


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## pfcs1 (Jun 7, 2003)

*Re: (pfcs1)*

re: ignition timing- the actions of the ECU towards timing was something I chose not to deal with. Not knowing what is REALLY happening to something so basic and important as timing is scary. I bypassed the ECU by tapping into the harness near the ecu and picking up the Halls signal and running that to the ignition amp, cutting the signal wire from the ecu to the amp @ the amp. If you do this, the ignition timing will be WAY off and needs to be reset. (I had planned to be able to toggle from straight up timing to ECU processed, but the ECU changes the timing by +/- 60*! from Halls trigger signal. I've been running 29* timing until I can resolve the ****ty fuel curve issue, at which time I'll get on a dyno and tune fuel and timing. I can tell you that on high test pump gas, there is no problem running with 29* constant timing. My C/R is nearly 10.5/1 and you can floor it off idle with no pinging and excellent trottle response/low end torque. 
The point of all this is that I don't see how you can tune without info (unless you watch timing with light on chassis dyno). Perhaps you're going super-rich which stops detonation problem and so the ECU isn't retarding ignition-which confuses the issue. The only other person I know with the AMS chip reports that it runs too rich in a nearly stock application for him to use it. That's entirely consistent with my experience (having to run @35psi and still being too rich @6000). How do you know that its too rich other than that if pings?


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## DanielAdams (Aug 22, 2002)

*Re: (pfcs1)*

wow, some good long posts with actual sink-your-teeth-in information http://****************.com/smile/emthup.gif 
I'm still reading through it all to be honest, but all I can say is that instead of reprogramming the chip (as you suggest) I intend to fudge the same effect through balancing adjustable FPR pressure, VAM spring (if necessary) etc. And, a thousand apologies to all who are wating, but I've still not fitted it. Soon....


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## FastLapRSII (Jul 15, 2001)

*Re: (DanielAdams)*

Daniel Adams, I've been wondering for a while now, how does euro Digi-2 work w/o a lambda probe?


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## DanielAdams (Aug 22, 2002)

*Re: (FastLapRSII)*


_Quote, originally posted by *FastLapRSII* »_Daniel Adams, I've been wondering for a while now, how does euro Digi-2 work w/o a lambda probe?

Beats me







I guess it just runs ins (hopes he gets this the right way around for once) open loop mode, just looking up values in tables based on rpm, VAM opening and temperature and grabbing a fuel injector duration value. It just doesn't correct for o2 sensor reading like yours does I suppose. As pointed out before, Euro digis are slightly more powerful than US digis, possibly because the US system with o2 sensor adjusts the table value by knocking back the fuel level to the minimum that will still run the car in order to improve emissions.
Refresher: I'm trying to fit a derestricted BMW 533 VAM to my digi mk2 8v...
Aaaaanyway, I finally got around to fitting my VAM yesterday. I was doing a few other under-hood bits and bobs such as my adjustable FPR at the same time (which went well, but that's beside the point) but I basically didnt get the VAM working as I wished.
I plumbed the VAM in as a direct replacement for the original and connected up the stock wiring plug. It started but then died. I did this about 8 times, trying to find a throttle position that would keep it happy and stay running, but there wasn't one. whether i gave it on throttle or full throttle, it just died off from originally starting, gave no indication that it was responding to the throttle at all.
Since we compared the two VAM resistance curves and found them to be pretty similar, I'm going to guess that its a matter of the spring resistance inside the VAM and that, most probably, the spring tension is too great and the flap is not opening sufficiently and thus the engine is being choked of air.
I noticed that just right after it died it 'clanged' a few times as if the VAM flap was clanging noisily closed a few times. Unfortunately it was just me working ont it and not even the girlfriend was around to help me by holding the flap open whilst starting it to see if it would run that way. SO it came out again for the moment
I'm having a car day this saturday across at a mate's house, so I will try again with an extra pair of hands ad see what happens. I'm definitely thinking that it will run fine if the flap is held open and that I just need to loosen the spring. Its not a straight plug-and-play swap in this case, however, it appears.
Soon as I do get it hooked up and running (however badly) I'll going to do a setup and tuneup on a dyno since the FPR and VAM will need to learn to be nice to each other.
Basically, more info to come saturday/sunday, but it is *not* a simpleplug-and-play swap as hoped.
For those interested, and following from comments posted above, the FPR is a 1.7/1 rising rate, adjustable from 3.0-4.0bar. I have it set at (stock) 3.0 at the moment until I do the dyno and get everything set up, but even at stock 3.0bar, the rising rate fuelling definitely makes a difference in seat of the pants driving.
Dan


_Modified by DanielAdams at 11:48 AM 12-19-2003_


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## docspeed1 (Apr 26, 2002)

*Re: (DanielAdams)*

Glad to see you're still working on this. I think you're on the right track with the spring tension theory. IMO, The bigger VAM would need to be at the same position as the stock unit at any given engine speed/load for the ecu to get close to the right reading. Your engine would be moving less air than the BMW's larger engine at any given load/speed, therefor the spring would need to be backed off to compensate. 
Hope it all goes well.


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## pfcs1 (Jun 7, 2003)

good going! I'm really curious to hear how it works out. I think you're absolutely right about softening the clockspring. Phil


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## Black_cabbie (Jul 16, 2003)

*Re: (pfcs1)*

Guys, 
Although its my first post in the thread (took me an hour to read it carefully), I can tell you that I've already tried to loose the spring in the MAF on a Euro GTI PB engine 112Hp stock. The results were not as good as I expected. The response at idle was improved but the car was running very rich until 4k and then starting to lean all the way until the rev lim. I saw an extra 2hp on top but the middle range become worse. I was running full Supersprint system,BMC cone filter and 270 Kent cam at that point. The dyno showed a nice 135 at the flywheel. Maybe with some headwork/bigger valves this mod would work fine but in my case increased the fuel consumption and of course I couldn't pass the MOT in UK.


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## docspeed1 (Apr 26, 2002)

*Re: (Silver_Cab)*


_Quote, originally posted by *Silver_Cab* »_Guys, 
Although its my first post in the thread (took me an hour to read it carefully), I can tell you that I've already tried to loose the spring in the MAF on a Euro GTI PB engine 112Hp stock. The results were not as good as I expected. The response at idle was improved but the car was running very rich until 4k and then starting to lean all the way until the rev lim. I saw an extra 2hp on top but the middle range become worse. I was running full Supersprint system,BMC cone filter and 270 Kent cam at that point. The dyno showed a nice 135 at the flywheel. Maybe with some headwork/bigger valves this mod would work fine but in my case increased the fuel consumption and of course I couldn't pass the MOT in UK. 


The issue is not the spring in the stock unit, but softening the spring in the bigger VAM to get it to work properly (sort of properly?)


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

free bump 
Just wondering if Dan got his setup running yet.
thinking out loud ,& I'm sure you all have figured this, the stock 3.5L BMW Inline 6 pulls a ton more vaccum than a hot 2.1 4 ever will, so reducing the spring tension will allow that 2.1 to suck the door open a bit to allow it to idle. right


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*


_Quote, originally posted by *Digiracer* »_free bump 
Just wondering if Dan got his setup running yet.
thinking out loud ,& I'm sure you all have figured this, the stock 3.5L BMW Inline 6 pulls a ton more vaccum than a hot 2.1 4 ever will, so reducing the spring tension will allow that 2.1 to suck the door open a bit to allow it to idle. right









Yep, thats a pretty good summary.Christmas got in the way of stuff - VAM spring meddling now in progress








Dan


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

http://****************.com/smile/emthup.gif 
CrAzy Dan, I hope to see some dyno numbers with it setup right before I permanently log off in a few months. 
Good luck with it. I know you can get it. We all got the basics figured out on page 1 and 2, now its time to test that hypothesis.


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## codydaniels (Apr 9, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Hey guys this might be an answer if we can get them to start producing them again http://www.hksusa.com/products/?id=858 what do you all think?


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (codydaniels)*

Hi all.
OK, a little progress today. I hooked the VAM up and left its cover off so I could make on-the-fly changes to the spring tension as I tried to get it working. To summarise, I basically found that with the clock spring unwound 10 notches (the spring feels noticeably more relaxed) the car will start and idle perfectly. Nothing untoward happens if you give it a little gas either, the revs gently rise as normal.
However, since I still don't have my A/F gauge working (*still* waiting on o2 sensor) I wasn't really wanting to F around with it too much and risk running silly-lean for too long (yes I'm a *****). I'm therefore going to wait until I have my A/F gauge working, tune the spring using this, then limp around until I can get it properly setup on a dyno with the adjustable FPR and VAM talking to one another. I haven't got the money to be rebuilding my engine so I wat to get it setup right.
I have no idea if its currently running silly-lean or whatever, but the car *seems* to behave normally with the cog spring unwound 10 points. Since we found the curve to be so similar to the stock VAM, it would not surprise me if the VAM will run as stock right up until past the point the stock VAM can't open any further, at which point it will start to run lean. 
Here's a piccie:








Not long until I have this thing completely nailed now, but the signs are encouraging








Dan


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

I LOVE YOU MAN! 
no, serious

I LOVE YOU, MAN !


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## FastLapRSII (Jul 15, 2001)

Would playing with the Throttle Body linkage to make both butterflies open synchronously help with the lower-end richness?
I dunno, has anyone calculated the area/flow of the T.B. at different throttle positions? Maybe it is also a restriction.


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## B3VR6 (Jan 4, 2000)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (FastLapRSII)*

Unless the extra air is unmetered, then it shouldn't make any difference other than to modify (steepen) the throttle input curve.
Remember, the air is still going to be metered and its volume measured.
If you opened the other butterfly to the atmosphere, bypassing the VAM, that would be another story.. I don't know how good of a story it would be, but it would be another one.


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## pfcs1 (Jun 7, 2003)

Dan-don't wait for A/F meter-check VAM load signal @6,000 rpm w/stock VAM under WOT acceleration in 3rd gear-you'll see around 4.2V.
Then soften you spring in the BMW sensor a little more if you"re concerned about running too lean and road test it the same as you did the stock one. I'd expect it to run a little rich now-and that the load signal will go higher than the stock one did under the same conditions. Now you can re-tension the spring to bring it into coherence with the stock sensor, or you can play with letting it run richer.
Thinking about this-VAM load signal voltage is measure of toral engine airflow at any point in time. One should be able to compare changes from tuning, ie: install headers, multi-angle valvejob, camshaft, etc. to the extent that one can accurately/repeatedly measure load signal to 3 figure accuracy with ones VAM. A very interesting possibility, eh? If [email protected]= 100hp, does 4.4v=110hp (or very close)?
And let's see more posts on this string-this post is also a bump-how many peple out there are thinking? Phil


----------



## pfcs1 (Jun 7, 2003)

Dan-ps: what kind of sensor do you need. I have 3 spare 95 civic wideband sensors, brand new, unused, $350 list price, that I can sell for $200 each. These are the sensors used in the Teck Edge ver 1.5 units. Phil


----------



## pfcs1 (Jun 7, 2003)

pps: Dan et all: I'd bet the VAM adj makes the airflow meter work fine. Let's not forget that to make Digi II TUNEABLE, we need to be able to manipulate the FUEL CHIPS! If someone out there could be of any help in this regard, please let me know. And don't bother mentioning CSW, AMS, SNS chips-been ther/done that. We need to be able to tailor our own chips on a custom basis, and then we'd have a damn good/cheap fairly high performance EFI sytem. And if that wasn't enough, this chip knowlege would work to convert our lowly VAM ECUs to work with a MAP sensor, virtually becoming Digi I. Phil


----------



## B3VR6 (Jan 4, 2000)

*Re: (pfcs1)*

I would suggest MegaSquirt [1] if you're looking for the best tunability for the smallest investment. The problem is that MegaSquirt only controls the fueling, you still have to come up with something to handle spark. MSD 6AL? Other than that, your options get more expensive quickly. You could probably find a used Electromotive Tec-II system for $1500 or so from some of the hard-core enthusiasts going to TEC-III.
Oh yeah.. forgot.. when you go MegaSquirt, you convert to MAP.. I guess that would make this entire thread pointless.
There is talk of an integrated system by the creators of MegaSquirt that will do ignition and fueling [2]. I know they already have a separate Ignition system. [3]
[1] http://www.bgsoflex.com/megasquirt.html
[2] http://www.megasquirt.info/UMS.htm
[3] http://www.megasquirt.info/Ignition.htm
EDIT: Here's a link to some video clips of a person running MegaSquirt n' Spark for their ITB'd 83 GTI.
http://autos.groups.yahoo.com/.../1611


_Modified by B3VR6 at 8:30 AM 1-5-2004_


----------



## Assimlatr (Dec 16, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Okay so I have been toying with this idea...but let me give some backround first (good post too).
Had a Ranger pickup a while back, and was going to convert it to a Turbo Ranger. I got as far as purchasing the computer, VAM, injectors, and chip (eBay...great deal). Then I got a "real" vehicle...my 92 GTi. It is a Cali-Digi1...the one with the VAM. Afterwhile got tired and started modding.
The restriction is contained in the whole intake. The VAM measures out at about 2.5 inches in diameter. The air-tube to the throttle body at the smalles point...is about 2.25 inches. The throttle body itself at wide-open is close to about 3 inches in diameter (cumulative). There is a lot of restriction.
After getting a dual-down, I busted out the 3-inch PVC and got me an airtube. I also got an AMS chip. In speed trials (on a back-road), with using the airtube as a reference, I go to about 90 mph (stock) to 95mph (airtube)...big increase from just replacing the tube.
Then I thought about the VAM. The ford one is a bosch meter with about a 3 inch diameter hole on it (from a 87 Thunderbird TC). I fitted it...loosened the spring (with the help of a DVM) and got it up to 100mph (Ford VAM).
That is a lot of restriction lifted. For about a month I monitored the signal, about the same time I also got an A/F meter (cool...in the gauge cluster...my own design). I got a little lean in the top, but with further tweaking on the spring...I can now do 104mph (Ford VAM with adjustment). It still gets lean at the top, but now it is ping and the need for fuel. *THAT was my old idea*
*So you want a MAF.*
I have been thinking. A standard hotwire MAF from a VR6 is roughly 3-inches. The thing that is different is that the signal from the MAF is digital (frequency based) and has a burn-off cycle. VAM has a voltage signal and has an Intake Air Temp sensor.
*So lets examine some properties*
-Since the VAM is based on a spring...the signal bounces all over the place. However...even the stock VAM does not peg a 4000rpm (least according to my DVM)
-The VAM only accounts for the volume of air running through, while with the IAT, the computer does the rest to account for mass (mathematically)
-The MAF measures mass, taking into account tempurature and altitude.
-The MAF has a steadier signal.
-The MAF has a burnoff.
The computer should be able to compensate for the steady signal, but since the MAF already takes into account the air temp, there would be a double reading, and the system would lean out.
*So here is the meat and potato...my idea*
With the help of a PCB board and a soldering gun...it is possible to make the signal from the MAF (frequency based) to the VAM input (voltage based). It is a chip by National Semiconductor, frequency to voltage convertor. Based on what reference resistors are used, one should be able to taylor the signal to emulate the VAM.
Next, take the Intake Air Temp and replace it with a single resistor. Prefereably of a known value in the table. (Those with digi-1 CA might have an issue resetting the computer...so a POT would be better...so on reset you can dial in the ambient temperature). This eliminates the double reading, by fixing one of the variables (so that if it is needed...a chip tune can really neglect IAT readings)
Now for the burn-off. I am not much of a programmer, but a PIC-Basic PROM setup ought to do it. Based on the Probst Bosch FI book, the burnoff happens only if the engine is run above 3000rpm during operation. It does not activate if the engine dies below 200 rpm (this is for LH-Jetronic, but digi is essentially L-Jet, and LH is a slight mod to L). 
All I have to program is an RPM monitor and Ignition sense monitor that flags when 3000rpm is hit, and will deactivate the flag below 200rpm with ignition on. Once the ingition turns off, I need a counter that goes 4-seconds, sends a signal to a relay for 1-sec (burn-off), then powers down.
Minus some adjustment misgivings for a CO%...theoretically this should work, and it is standalone. This means that any VAM vehicle could use this, not just VW.
I have only yet to build and test it


----------



## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Assimlatr)*

beautiful, If I were to run a true MAF I would start out with an ABA or VR MAF. Very good statements made. Hopefully we can grasp a few new working models and eventually find out which method is cheapest/most accurate etc.


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

I just swapped a BMW 535i AFM in my Golf & I drove it tonight







.
The car runs really lean so far. I have a Cyberdyne Air/Fuel Gauge keeping track of things. When I accelerate the gauge goes completely lean but when I let off or stabilize my foot position, the gauge climbs back to stoich (14.7:1 ish) It pinged alittle from what I could hear but seemed to run ok aslong as I kept the load off it. I only drove it for about 15 minutes I just wanted to give you something to chew on. Right now the car has 2.0L aba injectors (which flow alittle less 189cc vs 205cc for the stock digi2 injectors. I have a new set of digi2's i'm going to put in tommorow (if it's warm enough) & I'm going to pick up a Porsche 3.5 bar FPR on the way home from work. That should fix the fueling issues. http://****************.com/smile/emthup.gif 
I got on it hard (floored it in 2nd gear hoping WOT mode would supply some more fuel but the gauge stayed lean. I was amazed, I hit 6,500 rpm in 3rd gear & it seemed like it was still willing to pull higher. I have an AMS chip w/ the rev limit raised to 7,000 rpm so I'll find out if it'll pull up higher once I get the fuel sorted out. 
I'm also thinking about doing a resistor trick in place of the coolant temp sensor, & just run it like 12.5:1 across the board w/a 1k ohm resistor from Radioshack. I need to get some sleep, i'm about to pass out, I'll keep you all posted, props go to Dan A.


----------



## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*


_Quote, originally posted by *Digiracer* »_I just swapped a BMW 535i AFM in my Golf & I drove it tonight







.
The car runs really lean so far. I have a Cyberdyne Air/Fuel Gauge keeping track of things. When I accelerate the gauge goes completely lean but when I let off or stabilize my foot position, the gauge climbs back to stoich (14.7:1 ish) It pinged alittle from what I could hear but seemed to run ok aslong as I kept the load off it. I only drove it for about 15 minutes I just wanted to give you something to chew on. Right now the car has 2.0L aba injectors (which flow alittle less 189cc vs 205cc for the stock digi2 injectors. I have a new set of digi2's i'm going to put in tommorow (if it's warm enough) & I'm going to pick up a Porsche 3.5 bar FPR on the way home from work. That should fix the fueling issues. http://****************.com/smile/emthup.gif 
I got on it hard (floored it in 2nd gear hoping WOT mode would supply some more fuel but the gauge stayed lean. I was amazed, I hit 6,500 rpm in 3rd gear & it seemed like it was still willing to pull higher. I have an AMS chip w/ the rev limit raised to 7,000 rpm so I'll find out if it'll pull up higher once I get the fuel sorted out. 
I'm also thinking about doing a resistor trick in place of the coolant temp sensor, & just run it like 12.5:1 across the board w/a 1k ohm resistor from Radioshack. I need to get some sleep, i'm about to pass out, I'll keep you all posted, props go to Dan A.









Congrats mate. As you say, a higher pressue FPR (or an adjustableone) should sort you right out - nice one








Just gutted that you're driving around with yours working before i am mine - I cannot get mine running what i would consider acceptably and get stalling etc. Given that you got it working straight off the bat I guess my VAM is most probably slightly damaged - either the tracks might be worn too much or else the arms bent slightly, who knows. i'm going to persevere with this unit for a while and then search out a replacement if that doesnt work.
For the time being here's a (now fairly redudant) link on the flapper vane air meter, albeit with some info on how to setup your car after fiddling with the VAM:
http://www.gomog.com/articles/EFIflap.html
EDIT: and some more long-lost info from back in the day (1991) found in an old mailing list archive:

_Quote, originally posted by *oldstuff* »_Once the cover is removed by breaking
the silicone seal, there are several adjustments available. Among
them:
spring bias - serves as a span adjustment
wiper offset - serves as a baseline adjustment
segment resistors - calibrates the mixture at a particular
throttle opening.
The wiper offset adjustment, accomplished by loosening the screw that
locates the potentionmeter wiper on the flapper shaft, has the most
marked effect on the low end of the range. This is because the 
resistance vs flow is very non-linear and the most rapid change is 
off-idle. Small changes make BIG mixture changes.
Changing the segment resistors, while a lot of work, is well worth it.
One can then change the mixture at a particular flow that might be 
problematic. the segment resistors are those laser trimmed silk screened
resistors that shunt various parts of the main pot. resistance.
The procedure is as follows:
Cut one trace to each resistor as near to the resistor as possible.
Measure the resistance and record it. Select a 10 turn trim-pot
equal to twice the value for each resistance. This means that the
pot will be set at approximately the midpoint for stock conditions.
Mount the pots appropriately. Very small pots can be fit under
the cover. Larger ones can be mounted in a small box with wires
run to the flowmeter. Attach the wires to the main resistance by 
carefully scraping the traces to the old resistors clean, superglueing
a wire down to each trace for mechanical strength and then making
the electrical connection with silver-bearing electrically conductive
paint (or epoxee if you have it.) The paint for repairing rear
window defrosters works fine. The wires should connect such that 
they connect to the traces upstream of where you cut the original
resistor out of the circuit. It should duplicate the electrical circuit
of original setup.
Calibration is most easily accomplished by setting each pot to the midpoint
by measuring the ohms before glueing them down. After the pots are 
bonded in place, connect a voltmeter between the low end of the pot (where
the wiper rests when the engine is off) and the wiper. Run the leads
so that the voltmeter is in the cockpit. Drive the car and note the voltage
at which some problem is observed. Stop and manually position the air flapper
until you get the same voltage reading. Then observe the arm position 
and notice which pot spans that location. That pot can then be adjusted.
As you might expect, the adjustments interact so make small ones and 
keep careful notes so you can duplicate where you were last when you
screw something up.
An exhaust analyzer makes the task much easier. Inexpensive lambda
sensor-based units are available from MSD and Summit Racing. tuning
the air flow meter combined with adjusting where the WOT contacts
make up on the throttle body (essentially a step change enrichment.)
will yield a very responsive engine that can easily pass an idle
emissions sniff test.

Dan


_Modified by DanielAdams at 11:28 PM 1-13-2004_


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Update: I've been driving the golf everyday, (having trouble w/ my Corrado)Anyway, the car is running awesome, my 3.5 bar FPR hasn't arived yet so I had to use a 4.6bar unit I bought from a Vortexer that I forgot I had laying around. No injector lockup problems sofar. The 2.0L injectors are still in place. (it's been too cold to change them out) Upon start up the idles kinda low at about 700 rpm & cold start mode doesn't engage right away. I sit there for about 30secs giving it alittle gas to keep it from stalling. It idles like a watch @ 1,000-1,000 rpm once warmed up, no more idle variation now that the ISV is disconected








It does'nt not run overly rich at all, The ECU does a fine job of pulling the injectors back alittle even with the additional fuel pressure.
@Idle: Once warmed up, the A/F Gauge reads 14.4:1 w/an occasional spike to 13.8:1
Around town driving, A/F Gauge reads 14.4:1 everywhere again sometimes spiking to 13.8:1 but rarely & @ lower revs
In WOT Mode, the A/F Gauge goes to 13.2:1 
please note: these readings are the same as before with the stock unit in place, this is how the AMS Chip fuels regardless of the size of AFM
I was playing around last night, & got on it through the gears & I hit 
6,800 RPM







in 3rd. I think it'd pull to 7,000RPM (revlimiter) if I retarded the cam alittle. Who says 8Vs can't make power up high?








I'm really pleased though, w/ the stock unit the engine would run out of steam past 5,500 RPM. How does it feel? It drives like stock w/an extra 10-15 HP everywhere (all throttle positions) according to the butt dyno
I plan to get the car on the dyno soon & get some real numbers for you all. 
So was it worth it? Definetly, Any drawbacks? none so far
I payed $60 for the BMW 535i AFM, $36 for a 3in K&N filter & 10-20 for 3in piping.

_Modified by Digiracer at 11:36 AM 1-17-2004_

_Modified by Digiracer at 4:43 PM 1-17-2004_


_Modified by Digiracer at 9:21 PM 7-13-2004_


----------



## FastLapRSII (Jul 15, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

Would a 944 AFM be any better than a VW one?


----------



## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (FastLapRSII)*

Congratulations to everyone who participated. We all pitched in ideas etc that helped advance the progress of this project and though only a couple had the time, money, ambition, etc to execute it. It worked. I look forward to seeing fuel and power dynos soon. again, awesome job guys!


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

A bit belatedly given that digiracer beat me to it







but I've found a replacement 535 VAM at a local scrappie to replace the 533 VAM that I think I damaged the pickup arms of doing all the testing earlier. Should have it hooked up in the next week or so (busy with a funeral and stuff) and (since I'm out of work right now) will get it dynoed almost originally so we can get some numbers for what we now know works. I'll post up side-by-side dyno plots from the before and after, and will have it done at the same place as before http://****************.com/smile/emthup.gif 
Dan


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## GTi_94 (Oct 10, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

I've been reading the first part of this thread and it is very promising, I just thought I would add my 2cents for what they are worth
I am a 16v digi2 owner and I throughly agree that something needs to be done about the VAM.
I am currently in the process of build a "test harness" that will allow me to attempt to use any of the mk4 style maf's on my car, the info that you have provided is very usefull. sounds like you have made major headway on the bmw VAM which is great as splitsecond makes maf covnersion for those bmw's that you are using the vam's off of.
hope this isn't old news.....

edit:
I also have an aermotive adjstable fpr, that I will eventually be using....

cheers,
Bryan


_Modified by GTi_94 at 10:41 PM 1-24-2004_


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (GTi_94)*

GTI_94, one of these days I will need to ask you some questions and talk Digi 2 16v with you. I still have some work to go on the one a friend and I have built , but theres still a few unknowns that you should be able to help out with . So be ready


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Update: I Finally installed my 3.5bar FPR today. (had a crushed 4.6 bar unit in place) 
It's noticably more responsive at lower revs. I figure the ecu doesn't have to pull the injectors back with the fuel pressure now at a more normal level.
Sometimes in cold start mode the injectors would lock up @low revs. (too much fuel pressure w/the 4.6bar unit)
It's amazing how flexible this engine is now. I can loaf along in 4th gear @2,000-2,500 rpm & it's happy & still very responsive. (w/out the BMW AFM, the engine would bog heavily in 4th @ those revs.
I have 4K gearbox (3.94 R&P) 1st gear was worthless before but now 2nd gear is too, & I can easily break the tires in 3rd on a roll on.
My best time was 15.2 in the 1/4 with the stock AUG gearbox. It should have went a high 14-15.0 with the 4K(if I had traction







) As it sits now, I'm thinking mid 14s(again if I can hook up), I'm thinking about maybe getting a close ratio 16V trans with the 3.67 R&P 
This is a must do mod if you have a high HP 8Valve & almost a requirement if you want to make max power with your Digi216V.(unless someone finds a better alternative)
A few guys running Digifant1 16Vs are putting down some amazing numbers like 160+ whp








I seen a few guys making 140+whp with near stock Digi2 16V setups. 
Just imagine what a larger MAF or AFM will do for a 16V.








GTI_94 thank you for stopping in, keep us updated if you find anything in your quest for MAF. http://****************.com/smile/emthup.gif I've been trying to get some Digi216V guys in on this.
ps.
some have asked for the part# on the AFM unit, sorry I took so long anyway: part# 0280 203 027 it's a Bosch Unit btw



_Modified by Digiracer at 9:24 PM 7-13-2004_


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

Digiracer: can you give us more details about the fuel pressure regulator you're using? (Price, part number, etc) I'm hoping to do this mod next week- lots of BMW 535s in the boneyards here- but I've got to budget for everything


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

The Fuel Pressure Regulator I'm using is a Porsche 3.5 Bar unit for a Porsche 944S
the Bosch Part# 0 280 160 263
Porsche # 944 110 198 03
I ordered mine from Bahnbrenner for $70 to my door.
I got ripped off








I just found 3.5 bar FPRs through Germanautoparts.com for only $41 http://****************.com/smile/emthup.gif 
http://www.germanautoparts.com


_Modified by Digiracer at 4:41 PM 1-28-2004_


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

Great! Thanks Digiracer.
One other question for everyone- is a custom digifant chip a necessity? (for those of us who are unemployed, but still want to go fast)








Thanks!


_Modified by benzboyracer at 8:42 PM 1-27-2004_


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## VWradar (Apr 20, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

This is some great info. So when you put the BMW AFM on, is it a straight bolt on? I hope it will help my set-up: 2L (3A), 272 cam, VW_Piolet chip. Would the G-60 injectors be to big? Do you think I should get a different chip, like SNS?


_Modified by DCIvwRadar at 9:15 PM 1-27-2004_


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## B3VR6 (Jan 4, 2000)

Impex has that 3.5bar FPR for $53:
http://www.impexfap.com/partli...29188


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

Glad I can help Benzboyracer. If you're on a budget & don't want to spend the $$$ on the AMS Chip I'd definetly consider the SNS Digifant2 Cam Chip The SNS Chip adds fuel & it's only $39 http://****************.com/smile/emthup.gif What mods do you have on your car?
DCIvwRadar this is one of the easiest bolt ons w/ the most dramatic improvement. All you need is about 1.5 feet of 3inch intake tubing, 2 rubber/silicone hose joints, 3 clamps, & a 3inch K&N style cone filter.
You cut the intake tubing to the desired length.
The BMW AFM will plug right into the OEM VW Connector.
The spring tension on the AFM must be unwound 8 clicks+or-.
Your stock injectors are fine, it's the stock FPR that needs upgraded.
You should be okay w/ the chip you have just get a 3.5 bar FPR to keep things safe.
http://www.germanautoparts.com
i found the 3.5 bar units on the SNStuning web site for only $41 through germanautoparts.com


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## GTi_94 (Oct 10, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

Thanks guys, with all of this info, I am strongly looking into upgrading my vam to either the bmw one, or else one of the split second kits for the bmw's you are using the vam's off of.
I am still currently trying to retrofit the AEG maf, but the afformentioned issues will have to be over come still.
would g60 injectors be a good idea or what injectors do you guys think I should try and run? should I dial my fpr in at 3.5bar or more?
so the bmw vam made that big of a difference? bmw guys see that kind of a difference when switching form the vam to a maf.... maybe losing that much intake restriction will allow for insane power increases, and a better realization of what potentional these cars really have.
by loosening the the spring tension 8 teeth or so, how does this affect the mixture? does it make it richer or leaner?
what would be the best way to create or hook up an a/f ratio gauge?
exactly what year/model did you get your vam off of digiracer?
cheers,
Bryan


_Modified by GTi_94 at 8:18 AM 1-29-2004_


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (GTi_94)*

GTI_94 The stock Digi2 injectors are a good size (205cc) If I were you i'd just up the fuel pressure, using a A/F ratio meter & go from there.
If I were you I'd be looking for an AMS Digi2 Chip because with a 16V your going to easily make power past the stock 6,200 rpm limiter in the stock Digi2 ecu. The AMS will let you rev to 7,000 rpm. fwiw I hit 6,800 rpm with my 8V.








Yes the BMW AFM made a huge difference, big gains in torque & HP up high. The gains will be even more dramatic on a 16Valve. If someone already made 140+ w/stock Digifant2 AFM you can expect close to 160hp with this BMW AFM.
Hooking up an A/F Gauge: 1 ground wire, 1 power wire (hook it to a ignition switched lead) 1 signal wire, just tap the signal wire off the O2 sensor. Note: our O2 sensors are heated 3wire units, take special care in not wiring your A/F Gauge to one of the heated wires (this can fry your A/F gauge)







use a volt meter to find out which is which
Loosening the spring tension 8 clicks allows this engine to idle. It does not affect the mixture at all. The ECU controls the mixture. This unit is off of a 3.5 liter Inline 6 these pull a ton more vaccum than our little 1.8's & 2.0L's.

My BMW AFM is off a 1987 535i part# 0 280 203 027




_Modified by Digiracer at 6:22 PM 1-30-2004_


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## GTi_94 (Oct 10, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

If I could find ams I would, but no website no info no nothing...
thanks for the help though digiracer!
currently I am running a digifast chip
cheers,
Bryan


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (GTi_94)*

here ya go:
http://www.advancedmotorsport....


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## GTi_94 (Oct 10, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

thanks!
any idea where on there website I would find some information about there chip?
so yoru thinking that the stock digi2 injectors and 3.5bar fpr is the way to go? or should I be running more fp?
I am contemplating trying one of split-seconds maf conversions...
cheers,
Bryan


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (GTi_94)*

Some of you may think I'm a retard for doing this but:
I took the Golf on a short blast down I-480E at 130mph







& I hit the 7,000 rpm revlimiter in 4th gear 107 mph








I found out aproximately how fast I was actually going with this link
http://www.nwlink.com/~vdb/vw/...tml

This would not have been possible with the stock AFM so I figured I'd share. 
I would've loved to have seen the little Dub from a 3rd person persective burn the tires accelerating hard onto the on ramp in 3rd shifting @6,000 rpm then into 4th holding 4th until the 7,000 rpm revlimiter kicked in & then shifting into 5th holding till 6,000 rpm. I thought I was going to break the speedo (120 mph speedo) Note: I've never been able to rev it to 7,000 rpm, I'm sure it would have in 1st & 2nd, but what's the point if it doesn't really make power there.
I haven't even done any tuning yet, i still want to throw the new set of Digi2 injectors in, advance the timing some more & retard the cam timing alittle, change the plugs, new cap & rotor, new fuel filter & some fresh Mobil1 Fully Synthetic 0-40W I'll be on the dyno soon, possibly the end of this week, It's just been so damn cold out












_Modified by Digiracer at 2:21 AM 2-1-2004_


----------



## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

Digiracer, you go mate!








I fitted my 535 VAM today also (at last) . Still gutted I didnt get mine setup before anyone else (







) but its done and its running fine. I think my suspicions of having damaged the tracks on my original BMW VAM were correct, since this second one ran great. I'm running with 6 notches at the moment (i think, maybe 7) since that was the minimum needed to get a good idle. Remember this is on a 2.1 with work done to it so probably pulls a little more vacuum than a stocker at idle.
Anyway, it starts, it runs, I've given it a little hiding around town and it *seems* to be good - its certainly a little more responsive but I'm not sure yet whether there is a power increase - the best way to describe it is the engine feels a little less inhibited, a little less held back.
I am in a good position to get a dyno done too - nothing on this coming week, so I will definitely get it booked in and dynoed as early as possible. I will get it dynoed at the same place as before and post up the two dyno charts side by side, possible pchop an overlay of the two charts etc, it will be interesting to see whats changed (original dyno sheet here). I have fitted an adjustable (3.0-4.0 bar) FPR (after the first dyno but before I fitted the VAM) but apart from that no changes inbetween the two dynos other than the VAM swap. I intend to do an initial run, correct the fuelling based on the mix readout and then give it a balls-out to to-the-limiter run like the first dyno for comparison to get some actual figures for you guys so we can quantify the change.
Only thing that could hold me up is them not having a dyno slot anytime in the next couple of days, but this should happen by wednesday I would imagine
I'll keep you all updated.
Dan


----------



## DST VR6 (Sep 27, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

aaron, link doesnt work. but here ya go:
http://www.nwlink.com/~vdb/vw/....html
http://****************.com/smile/emthup.gif


----------



## VWradar (Apr 20, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (vwgroundzero)*

I e-mailed AMS about the chip and it's $300







for the cam chip. I'm looking for a BMW afm if anyone has one? Can't find one around here.


----------



## reflexbug (Mar 10, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DCIvwRadar)*

Found one on Ebay... 
http://cgi.ebay.com/ebaymotors...68010
It ends in 15 mins from this posting though... but if it doesn't sell on ebay, I'm sure the guy would willing to sell it to someone...


----------



## GTi_94 (Oct 10, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DCIvwRadar)*

it's not just a chip though, that's why you have to send them your ecu


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DCIvwRadar)*

DCIvwRadar are you sure the AMS Chips are $300? They used to be $300 back in the day but they went down to $199 if I'm not mistaken.
Here's where I got my BMW AFM, they have a bunch for $50 a pop.
http://www.intercityauto.com/



_Modified by Digiracer at 6:06 PM 2-2-2004_


----------



## VWradar (Apr 20, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

I just e-mailed them the other day and that is what they sent me back.
That page could not be found










_Modified by DCIvwRadar at 10:15 PM 2-1-2004_


----------



## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DCIvwRadar)*

dyno booked for 1pm thursday


----------



## GTi_94 (Oct 10, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

this is a great, informative thread, keep it up guys!


----------



## worm68 (Dec 18, 2003)

great info guys on the digi 2 i am about to do a 2l 16v in my 91 gti we have a car at our that's a digi 2 we're having trouble finding out why it wont run right with the cts plug in. we change it check everything u suppose to but it still does it its a new senser it starts missing real bad about 3500 rpm without it pluged in it runs good i thought i would ask u guy's what's up withit u seem to know alot about digi 2 thanks


----------



## GTi_94 (Oct 10, 2002)

*Re: (worm68)*

I had this problem when I had my old red 16v, I had converted it to digiII, it kept runnign rich, I finally got everythign dialed in and it ran like a top, a day later it got totalled..... so I hope that helps!


----------



## DanielAdams (Aug 22, 2002)

*Re: (GTi_94)*

Right, I'm back from the dyno, and here's what I found. 
Short version: no new dyno chart, sorry! Anyone want to lend me $70 for another dyno session?









Long version: what? Dan you maniac, you mean to tell me you spent an hour and $70 on a dyno and didnt bring us a dyno sheet to show for it? Basically, I never got a full run in because we were so busy tuning the mixture just right - even the setting on the FPR I thought was fine was actually too lean and had to be upped a bit more. There's definitely some fiddling to be done to get the mixture just right and I'd personally suggest an adjustable FPR is a better bet if you can afford it than a set 3.5 or 4.0 bar unit - in additoin to the other tuning, we spent a lot of time going like 5-degree turns on the FPR screw tweaking it just right - it made quite a difference under load (maybe because its rising rate)
Anyway, we must have fiddled with the FPR at least 8 times in between short runs, then hit up the AFM idle mixture adjustment screw and finally the distributor - i have power figures etc for all the runs but nothing much above 5000rpm - I was 150bhp exactly at 4500rpm on my last run (presumably the most powerful) - I'll have to see how this compares to the first dyno sheet i did. I didnt do a single run over about 5k rpms tho because it was leaning out dangerously on the earlier runs and then I ran over my hour slot badly and couldnt push my luck asking for another run since there was a black TVR waiting to have a go and the high oil temp meant that there was a slight oil sump gasket leak becoming apparent.
I was paying attention to two thngs mainly - the CO figure and the VAM flap position - the CO I finally got sorted at 2.7 at idle and IIRC about 5.5 throughout the top end. The car was running 92 deg oil temp starting out rising to 106 deg at the end. Water temp remained in mid-range. The VAM flap at top end in fifth was near as damned wide open. I'm convinced this is an essential mod for big hp 8v or digi2 16vs unless you want to go expensive and switch to ITBs or standalone engine mgmt.
On the way home after having it all setup tho - eeeek! I took the long route home to make use of this road coming into the backend of town - it's an old ROman road I think and is about 2 miles long completely flat and straight between two fields (yeah, I live in the middle of nowhere) and (whilst I backed off way before 130mph







I am absolutely 100% completely certain that it just keeps pulling up in the higher revs and doesnt run out of steam even at the top end of fifth. Sorry for not having the dyno sheet today to quantify this, but this mod definitely opens up the top end like you wouldnt believe.
I really want someone else to do this and get it dynoed so we have some figures (Digiracer!) but I have no dyno sheet for you today - sorry








End result: I'm completely satisfied with the mod and intend to drive it like I stole it for at least a few weeks until I grow accustomed to it and need to do something else for more power








Sorry for the long post and rambling but thought you'd want to know even though it wasn't the dyno sheet promised http://****************.com/smile/emthup.gif 
Dan

_Modified by DanielAdams at 2:33 PM 2-5-2004_


_Modified by DanielAdams at 2:35 PM 2-5-2004_


----------



## MBRACKLIFFE (Jan 17, 2003)

*Re: (DanielAdams)*

Dan I was just curious as to what other mods you have done to your motor so I would have a better picture of what to expect if I do this MAF swap.


----------



## GTi_94 (Oct 10, 2002)

*Re: (MBRACKLIFFE)*

yes me too


----------



## DanielAdams (Aug 22, 2002)

*Re: (MBRACKLIFFE)*


_Quote, originally posted by *MBRACKLIFFE* »_Dan I was just curious as to what other mods you have done to your motor so I would have a better picture of what to expect if I do this MAF swap.

My motor is pretty heavily modified already - if this mod works as we expected then it doesn't really add power throughout the rev range, I wouldnt expect, because at low load the throttle body is going to be the limiting factor in how much air can get into the engine. Basically, this mod helps at the top end - high load, high rpms, where you're flooring it and the TB is wide open - it just removes another restriction in the intake path and gives your motor a greater "ceiling" - everyone has noticed that 8v digis tend to die after about 5000rpm on the dynos and fall off sharply - this mod is intended to lessen that effect.
I would say that the greater the hp you were making, or the more mods you had (basically if you're flowing more air - eg digi2 16v, high hp 8v) this mod would be more useful to you - I think the effect would be lessened on a stock motor because it is going to be needing less air at the top end anyway since it can't flow as much. If you're running a digi2 16v, or an 8v with headwork, a 2.0 block etc, this is where I think the mod will be most useful in de-restricting your top end power.
My setup is fairly heavily modded - a 2.0 block, 1.8 counterflow head P&P, enlarged inlet and exhaust valves, portmatched manifolds, block bored/stroked to 2.1, balanced etc etc.
I know that Digiracer is planning to get a dyno done and if and when I get some more money I will do a proper power run on the dyno too so we can properly quantify it. Only thing we have so far is Digiracers 7000rpm limit in 4th (which he couldnt do before) and my seat of the pants feeling the top end keeps pulling like it didnt before.
Dan


----------



## B3VR6 (Jan 4, 2000)

Daniel, 150hp (is that wheel or crank?) is awesome for only 4500RPM or so!
I have a stock bottom end (tired, with over 180kmi) but a P&P counterflow head, shaved to the point of interference, portmatched manifolds, 270º cam, AMS chip (tuned for cam), exhaust, no cat, cam timing gear.
I bet that I wouldn't make use of the larger VAM now, but I plan on punching out an ABA bottom 0.040" over and giving it a set of Total Seal gapless rings along with a lightened flywheel and balancing. Right now, my car pulls from 3500 all the way to 6500+ with it dropping off only ever so slightly after 6500 (I think it's due to balancing and the bottom end's age.)
When I was in the middle of tuning the new head/cam setup I dialed in 2-3º of base timing advance... it pulled like mad from 3k before it started pinging badly above 5700 so I set it back. I think with these mods, a fresh bottom end and some extra fuel pressure I can get away with that extra base timing.
*My question:*
How much larger are your intake and exhaust valves over stock? Any idea how much more of a difference that made versus the same head with stock valves? Are your new valves back-cut? Any other tricks we should know?
Thanks again for all your work on this project and the information you're giving back to the 8v performance enthusiast community. It sounds like you're making power that gives the 16v guys a run for their money.


----------



## VWradar (Apr 20, 2001)

*Re: (B3VR6)*

Any new info? Don't let this wonderful thread die.


----------



## GTi_94 (Oct 10, 2002)

*Re: (DCIvwRadar)*

sorry guys, I just couldn't resist, I broke down and bought the splitsecond maf conversion kit


----------



## VWradar (Apr 20, 2001)

*Re: (GTi_94)*

How much and where?


----------



## GTi_94 (Oct 10, 2002)

*Re: (DCIvwRadar)*

it is seriously not cheap but it comes with the ability to tune your mixture on the fly and an a/f ratio gauge.
it was $875usd retail, I bought it through my wholesale account with them though, so I got it a decent bit cheaper...
http://www.splitsec.com/mafkits/universalkits.htm








cheers,
Bryan


_Modified by GTi_94 at 5:50 PM 2-12-2004_


----------



## Coupe__88 (Sep 14, 2003)

*Re: (GTi_94)*

Have you installed it yet? what is the adjustment on it. a screw or computer controlled?


----------



## DanielAdams (Aug 22, 2002)

*Re: (GTi_94)*


_Quote, originally posted by *GTi_94* »_it was $875usd retail








I wish you luck with it, but I don't think its really a "budget" option as the OP of the thread envisaged. Do let us all know how it turns out etc, if it works good perhaps we'll consider a sponsored 8v forum ram-raiding of their warehouse or something








Dan


----------



## GTi_94 (Oct 10, 2002)

*Re: (DanielAdams)*

LOL, no worries guys, I couldn't get my hands on a decent BMW VAM, and I was experiencing some other issues, so it was either this and maintain some of the features I love about digi, or go standalone again....


----------



## scottamus36 (Jun 13, 2002)

what years on the 535 AFM?...
Thanks for this thread !


----------



## VWradar (Apr 20, 2001)

*Re: (scottamus36)*

WOW!







I didn't know it was gonna be so much. So anyone know where to get a BMW VAM for cheap?


----------



## GTi_94 (Oct 10, 2002)

*Re: (DCIvwRadar)*

lol, sorry, I know they are not cheap, MAF's in general aren't cheap NEW, nor are our AFM's or VAM's whatever you want to call them... and for the fact of it being a kit and coming with a new maf and a airfuel ratio meter and some nice on the fly adjustment control's for mapping the mixture, it is worth it in my opinion, well at least for me it is with the amount of air I need to be moving through our "mousetraps"
just buggin, wish I could have been more help! keep up the good work though guys, this has been a very great thread and it' sbeen very informative, not only about what options we have but also about how the "mousetrap" works
cheers,
Bryan


----------



## Coupe__88 (Sep 14, 2003)

*Re: (GTi_94)*

Now for some dyno comparisons and owner feedback from both sides.


----------



## GTi_94 (Oct 10, 2002)

*Re: (Coupe__88)*

LOL
I'll try and keep you guys posted


----------



## MBRACKLIFFE (Jan 17, 2003)

*Re: (GTi_94)*

GTI_94 Now that you have your MAF kit maybe you should take it apart and tell us whats inside so we can build our own.. hehe...
On a serious note I wonder if just buying the controller box would allow us to use say a digi MAF. If the controller is doing all the signal conversion it might work unless it can only be used with their MAF.
GTI_94 Does the MAF have anything printed on it ie: who makes it?


----------



## GTi_94 (Oct 10, 2002)

*Re: (MBRACKLIFFE)*

I ordered it and it should be this here this week, I will try and answer your questions once it has arrived, but I am pretty sure it is a bosch maf, the controller box just manipulates the signal so you can tune your mixture still


----------



## Bondoboy (Feb 2, 2004)

So which maf should I get? The Bosch 027 or the 016? DanielAdams had the 016 that wouldnt run, so did you replace it with another 016 or the 027? I have either available to me but I wanted to get the right one.


----------



## DanielAdams (Aug 22, 2002)

*Re: (Bondoboy)*


_Quote, originally posted by *Bondoboy* »_So which maf should I get? The Bosch 027 or the 016? DanielAdams had the 016 that wouldnt run, so did you replace it with another 016 or the 027? I have either available to me but I wanted to get the right one.

I'm pretty sure I simply damaged the arms/tracks of the earlier 533 VAM i had (and that it too would have worked) but why chance it - yo've got two people who got the later 535 (027) VAM working without a problem, go with that http://****************.com/smile/emthup.gif 
Dan


----------



## username (Mar 27, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

ok, i haven't even finished the first page of this thread (please don't spoile the ending







), and i've already learned more about electrnic fuel injection in 15 minutes that i did my whole life until that point.
good work!
and yeah my head kinda hurts a little too


----------



## username (Mar 27, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (username)*

well i finally finished, and i can't wait to give this a try once i get my digi 8v gti out of storage and hand it over to a friend for some motor work (ABA bottom end, find out exactly what cam the previous owner put in it, rebuild head, etc) then i'm gonnna start monkey around with this set up as it sounds like a great fix for the drawbacks of running the digi2 system.
CIS loyalists... we're gunning for you









and again, thanks to everyone here for all the great knowledge, insight, reading material, and not so much for the terrible headache i have right now from all those damn anacronyms http://****************.com/smile/emthup.gif


----------



## vw1jetta (Sep 9, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (username)*

OK i have red some of this and will finish the rest in a while (lots to take in) but i have heard from a few of my tech friends that what it seems like you are trying to acomplish can be done very simple by taking and MAF from an A3 and replacing your VAM with it just take your wiring diag and re pin the A3 connector to your digi wiring digaram and it should work the only thing i didnt figure out yet was wich A3 MAF it takes seeing as their are about 4 different ones but owning a 88 jetta digi2 system car myself have been toying around with this idea for one simple fact that once this has been acheived then turbo should be no prob i will study a wiring diag monday when i get to work and see what i can come up with and if i have to call tech line for any thing and get a hold of bill by chance i will ask him if he not rushed for his input


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## MBRACKLIFFE (Jan 17, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (vw1jetta)*

vw1jetta: that sounds really interesting... if you find out more please post.
I would certainly like to know if this true as would everyone else watching this thread.
If your friends could do a short writeup or atleast get the specifics that would be great.
Anyone else tested a a3 VAM against the digi2 MAF ?


----------



## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (MBRACKLIFFE)*

the problem lies that the ECU receives a voltage signal from the MAF and a resistance signal from the VAM


----------



## mrkrad (Nov 9, 2000)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

If anyone can find me a reliable way to convert the HEATED MAF (note the power regulation for heating) to a resistance value. Maybe i'll be willing to work with a car i have access to to program a chip for it.
Probably will need an atmel/pic based cpu to rescale the MAF logarithmic values into linear.
You must understand the only reason they used a VAM is that it was LINEAR, and the cpu speed of digi-2 is so ancient, the conversion and math for some methods require a bit more complex (maps/algorithms).
Linear is far simpler to deal with.
I have an 88 digi-2 jetta i dont know if thats a performance engine or not, but i would use a dedicated wideband to do the tuning. 
If you guys don't know it yet, your cars run REALLY LEAN. SUPER DUPER LEAN. They need more (pulsewidth, more fpr) whatever you do. But if you don't be very careful you might turn that 14:1 A/F @ 6000 into 15:1 and torch a piston ..
I hope you can clean/read plugs if you are playing around with the injection and don't have a wideband. We have access to 2 different types (bosch/ntk) and I would highly recommend not mucking too much at high rpm's without knowing exactly where you stand fuel wise.
Your fuel pump should allow up to 5bar of fuel pressure, however you might not want to run that much if your motor can't swallow it.
It is the most logical way to add fuel. 
Basically the gist of the bigger VAM is an educated guess at a linearly larger scaled VAM and the equal amount of gas increase. If your VAM signal, i spose you could use a variable speed leaf blower to generate resistance values at specific amounts of air flow, then use excel to trendline compute the rest of the line on the stock/aftermarket VAM, then find the correctly (close enough) fuel pressure to scale injectors appropriate, then fatten it up (richness) so you can run higher octane, more timing without detonation.
Then you'd probably have your answer.
Keep in mind the 2.0 ABA made (how much stock/chipped). On a best day, you might not come near that since you have less stroke/bore unless you've put a 2.0 slug in. The ABA is also higher compression IIRC.
Alot of work and time. A junkyard low boost turbo could probably be done and run 5-7psi untercooled and make alot more fun for little $$ call me crazy but thats the truth.


----------



## eldo (Jul 26, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (mrkrad)*

boing. http://****************.com/smile/emthup.gif keep the opinions coming.


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## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (eldo)*

The first thing I do when I get home from my 2 year trip is to see this thread and hopefully see some crazy dyno charts and timeslips along with advancements in the swap







and maybe in 2 years I can look back and try to figure out why I ever typed OOOGACHAKA in this post.


----------



## benzboyracer (Aug 5, 2003)

Hey guys, here's a bump to bring this back up out of the ether.
I just noticed Digiracer asked about mods on my car (more than a month ago... oops. Sorry man).
I'm in the process of installing a TT268 hydro cam, Audi 5000 TB, port matched. I've got TT's 2.25 cat-back, dual downpipe, and there's some porting work in the future. SNS chip on its way, and the 3.5bar FPR. Next week I hit the boneyards to find me a MAF.
All that said, do y'all think there I'll get any signifigant gains?


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## Mr Black (Jan 20, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

Did SNS finally end up doing a Digi-2 chip? Are you the beta tester?


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Mr Black)*

Mr Black: From their site, it looks like SNS has had their Digi2 chip for some time-- its mentioned on page three or four in this thread, actually... 
As for being a beta tester... not that I'm aware of.










_Modified by benzboyracer at 8:09 PM 3-11-2004_


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## Mr Black (Jan 20, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (mrkrad)*


_Quote, originally posted by *mrkrad* »_Haven't dyno'd these but i spose if i ever find someone in atlanta i'll whip up a batch and spend an hour on the dyno to try them out and see whats up.

thats just my opinion. Due to no digi-2 car in atlanta to play with, i've really not had much attention to this car.


This is what I was commenting on. Maybe I misunderstood?


----------



## VWradar (Apr 20, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Mr Black)*

Anyone seen this post? http://forums.vwvortex.com/zerothread?id=1289372 Look about 10 posts down. They are talking about putting a Mustang MAF on the digi II cars and it will work


----------



## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DCIvwRadar)*


_Quote, originally posted by *DCIvwRadar* »_Anyone seen this post? http://forums.vwvortex.com/zerothread?id=1289372 Look about 10 posts down. They are talking about putting a Mustang MAF on the digi II cars and it will work









Quite possible if Ford used Bosch VAMs on the Mustangs, just like a bunch of other manufacturers of the era. The fact is, all of these will be calibrated differently and the trick is to find a VAM that is larger than the stock unit but whose resistance values are close enough (or the wpring can be tweaked to make them close enough) to allow the digi ECU to understand the values correctly in order to provide proper fuelling. We already have on candidate that works - the 535 VAM - so I don't see any need to go chasing other VAMs - unless you are saying the Mustang unit is a true MAF (ie heated wire type) that will somehow work with the digi ECU?


----------



## Coupe__88 (Sep 14, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DanielAdams)*

me thinks its a VAM labelled as a MAF or a MAF that plugs in and the ECU ignores it cause it has no idea whats going on.


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## GTi_94 (Oct 10, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Ford did offer a MAF conversion kit that replaced their barn door style VAM's
My split second kit uses a Ford MAF, I haven't installed the kit so I can't give you any feed back yet.
but from the looks of it it is a 4 wire as well and it should be really easy to retro fit to work, but the trick is that the S/S kit comes with an air/fuel calibrator about the size of one of our ecu's
I'm not sure of the risks of jus tinstallign the maf without the calibrator for the time being as I don't want to risk my built 16v....
cheers,
Bryan


----------



## OhioBenz (Dec 6, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (GTi_94)*

never messed with Rado's so what do they use?
I aquired a Digi-1 setup and want to put it on my 16v swap in the Rabbit!
maybe somebody can explain the diff between the Digi-2 & digi-1??
This is a great thread - Might have to try this on one of the Digi-2 jettas we got!!!
I got an chipped Motronic CIS-E in my GLI and its pretty decent


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## Mr Black (Jan 20, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (OhioBenz)*


_Quote, originally posted by *OhioBenz* »_never messed with Rado's so what do they use?
I aquired a Digi-1 setup and want to put it on my 16v swap in the Rabbit!

Digi-1

_Quote »_maybe somebody can explain the diff between the Digi-2 & digi-1??

Digi1 uses MAP sensor and a CO pot in the intake. Digi2 uses a weird MAF with a flapper valve doohickey which obstructs airflow similar to the CIS airflow plate. Both are chippable (different ECU's). The MAF is what people are trying to soup up in this thread by replacing it with a larger one.


----------



## vw1jetta (Sep 9, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Mr Black)*

Ive been meaning to post this sooner for you guys but havent had the time and honestly just ran across the book a couple of days ago
Quoted from 
VWOA inc
Service Trainig 
Printed in U.S.A. 2/88
Part #wsp 521-149-00
Second Edition
Digifant II Engine Managment System
Pg 12. Air flow Sensor
The air flow sensor measures the amount of air entering the intake manifold and sends a voltage signal to the control unit.
Intake air opens the air flow sensor flap wich actuates the potentiometer to determine the voltage signal. This signal and the eng. speed information supplied by the hall sender are used as the principal inputs for the determination of fuel injector opening duration and ignition timing points.
A compensation flap connected to the air sensor dampens sudden movements of the air sensor flap due to oscillations of the intake air.
End Quote


----------



## username (Mar 27, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (vw1jetta)*


_Quote, originally posted by *vw1jetta* »_Ive been meaning to post this sooner for you guys but havent had the time and honestly just ran across the book a couple of days ago
Quoted from 
VWOA inc
Service Trainig 
Printed in U.S.A. 2/88
Part #wsp 521-149-00
Second Edition
Digifant II Engine Managment System
Pg 12. Air flow Sensor
The air flow sensor measures the amount of air entering the intake manifold and sends a voltage signal to the control unit.
Intake air opens the air flow sensor flap wich actuates the potentiometer to determine the voltage signal. This signal and the eng. speed information supplied by the hall sender are used as the principal inputs for the determination of fuel injector opening duration and ignition timing points.
A compensation flap connected to the air sensor dampens sudden movements of the air sensor flap due to oscillations of the intake air.
End Quote


not to sound like a jerk.....but that was covered on like page 1







, these guys have been doing there homework http://****************.com/smile/emthup.gif


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## vw1jetta (Sep 9, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (username)*

I know thanx I had been meaning to post it earlier but had forgotten i had this book and had just run across it a couple of days ago http://****************.com/smile/emthup.gif


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## GTi_94 (Oct 10, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (vw1jetta)*

help is always appreciated though!


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## A2_CARAT (Nov 27, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (GTi_94)*

Ok, let me get this straight. digiracer(I think thats his username) has changed the air intake to 3" pvc, switched to a cone style filter, and changed the vam and fpr and the chip. This is stock besides those mods?? Do you have an 8v or 16v?? That seems like alot of gains for a little money. Not necessarily huge hp gains but drivability gains, ie. higher rev limits and more power above the 5000rpm mark, where I notice I have less the higher I go. WOW, great thread. Thanks for all the input by everyone.










_Modified by A2_CARAT at 7:09 AM 3-18-2004_


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (A2_CARAT)*

I just got the SNS fuel chip and FRP yesterday... I love it when things arrive together.








Both went in in about 15 minutes' time. Just from those two alone the whole exhaust note has changed, throttle response is much better, and it pulls like mad past 5K. Can't wait for the cam to get here!
Sadly, when I went off to dig up a MAF from the yards, I found they've all been pulled! Three yards searched, 10 BMW 535s, and NO MAFs. Grrr. Maybe I'll have to buckle down and order one for twice the money from one of those online junkyards.
All the Digi2 guys at my local meet are ordering chips and FPRs.







Props to SNS tuning.
Mr Black: I think what SNS's site is saying is that they've not had a Digi2 car to play with extensively.


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## username (Mar 27, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

i can't wait to put in my AMS chipped ecu this weekend....it'll go in the stock car first (red) and into the cammed car (black) when i take it out of strorage.
'course when i take it out of storage it will also get a ABA block, p+p, matched intake ports, full head rebuild with hd valve springs, valve job, lightened flywheel and a few other goodies


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## A2_CARAT (Nov 27, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (username)*

What bar is the stock fpr on our cars?? I found on snstuning.com a diy to chang a 3 bar to a 3.5 or 4.0 bar.


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## username (Mar 27, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (A2_CARAT)*

stock is 3...do you have the link for the diy article?


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## scandalous (Jan 4, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (username)*


_Quote, originally posted by *username* »_stock is 3...do you have the link for the diy article?

Yeah, post up the link...http://****************.com/smile/emthup.gif I have a few digi FPR's I could experiment with.
EDIT: 
Here's the link. Simple
http://www.snstuning.com/DIY/FPR/fpr.htm




_Modified by scandalous at 11:47 AM 3-18-2004_


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## username (Mar 27, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (scandalous)*

am i reading this right? you just smash the thing in a vice until it lets 3.5bar of pressure through?????


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## scandalous (Jan 4, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (username)*


_Quote, originally posted by *username* »_am i reading this right? you just smash the thing in a vice until it lets 3.5bar of pressure through?????









Yup...


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (username)*


_Quote, originally posted by *username* »_am i reading this right? you just smash the thing in a vice until it lets 3.5bar of pressure through?????









I know, it sounds a little crazy to me too, but thats exactly what they suggest, no more technical than that. I'm not going to diss the method, but I chose to go for an adjustable FPR myself


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*


_Quote, originally posted by *benzboyracer* »_Sadly, when I went off to dig up a MAF from the yards, I found they've all been pulled! Three yards searched, 10 BMW 535s, and NO MAFs. 

And so our VA meddling spreads like the plague...


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## A2_CARAT (Nov 27, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (username)*

I think you have found it already but here is the link anyways. http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://www.snstuning.com/DIY/FPR/fpr.htm


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## A2_CARAT (Nov 27, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (A2_CARAT)*


_Quote, originally posted by *A2_CARAT* »_Ok, let me get this straight. digiracer(I think thats his username) has changed the air intake to 3" pvc, switched to a cone style filter, and changed the vam and fpr and the chip. This is stock besides those mods?? Do you have an 8v or 16v?? That seems like alot of gains for a little money. Not necessarily huge hp gains but drivability gains, ie. higher rev limits and more power above the 5000rpm mark, where I notice I have less the higher I go. WOW, great thread. Thanks for all the input by everyone.









_Modified by A2_CARAT at 7:09 AM 3-18-2004_


anyone????


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## 89JettaCoupe (Jan 27, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (A2_CARAT)*

First of all, awesome post, I have been following it intently since I have digi2 as well. Second of all, i had never even heard of SNS tuning before, and was curious if anybody has used their digi2 chips?


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (89JettaCoupe)*

89jettacoupe: I just put one in my digi2 car, it's very good, seems to smooth out the throttle response and coupled with the 3.5bar FPR, it seems to pull harder at high revs. I've got the cam chip myself, but no performance cam yet (arrives tomorrow or Monday) so I don't really know how it's behaving yet. Even with the stock cam though, I can tell the car wants more airflow.
Regarding MAFs- went back to the junkyards today to look for rustang MAFs.. no dice. Just what's the black-market value on these things that they're gone before the cars hit the yards?


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## VWradar (Apr 20, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

Well I just bought one off ebay today. I'm gonna see if a AFM from a 633 will work. It was only $5 so if it doesn't I'm not out much. Will let you all know.


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## GTi_94 (Oct 10, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (DCIvwRadar)*

Started the Split second kit install tonight, all is going fairly smoothly, it said that the afc box converts some signals to work properly, but I want to get this kit in and see if I can develope a cheaper version.
sorry I didn't try it with JUST the FORD MAF first....
I'll let you all know how it turns out, and just a note of interest, if you cna get your hands on a AFR guage and just watch how bad our cars manage the mixture with the factory AFM even if it is modified with less spring tension.....
cheers,
Bryan


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## CheapXJ (Mar 16, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (gearhead455)*


_Quote, originally posted by *gearhead455* »_
Stab in the dark...
Actually I can kinda understand why there is a curve like that. If the throttle position is closed (TPS signal) and the resistance value is less than 900 ohms than the ECU knows the engine is at idle and maps accordingly. A soon as the throttle position shows off idle and a resistance value that jumps to 1000 ohms and then lowers, it know that the engine is being revved.









does anyone know if it will behave properly at idle if the value is left at 1000 ohms?
these numbers (from the chart) look VERY similar to what would be found on a GM MAP sensor, the operating characteristics are similar and a GM map sensor can be EASILY tweaked into the correct range.
I've got a couple GM map sensors layin around, and I think I might play around with it tonight. I don't know how well this will help at the upper end (may actually make it lean out more) but it will help at mid-throttle acceleration under load.
the digiII system just seems like it is built more towards efficiency than performance.


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## Assimlatr (Dec 16, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (CheapXJ)*


_Quote, originally posted by *CheapXJ* »_
does anyone know if it will behave properly at idle if the value is left at 1000 ohms?


Not really. I've been playing around with my stock meter (bad A/F probs trying to get 12.5:1 C/R figured out) and it seems that the VAM has to be at its maximum ohm value (i.e. if 1000 ohms is the max, then it needs to be at 1000 ohms at idle) or really close to max value. 
If digi finds that the Throttle position is closed and the VAM ohm value starts to fall, then it bumps the idle...thinking that the engine is dying. So you start to idle well above 1000 rpm. 
At a time (when I thought I had mine figured out) it idled at about 1900 because it was below the max value. (Spring was tightened alot...indicating a lower voltage signal to the computer).


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## OhioBenz (Dec 6, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Assimlatr)*

I've read through this thread a couple times and think you guys have done a great job!!
Is there a way someone could post - in a nutshell - what options that have been done & have worked? Kind of a summary to date?
I'm in the middle of a Digi-1 conversion but also have 2 other Digi-2 cars I might just have to play with....


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## OhioBenz (Dec 6, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (username)*


_Quote, originally posted by *username* »_am i reading this right? you just smash the thing in a vice until it lets 3.5bar of pressure through?????









a lot of the ricers have been doing this with their eclipses etc.


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## ALLGORIMSHOW (Jul 1, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (OhioBenz)*

ttt


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## mrkrad (Nov 9, 2000)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Back_yard_mechanic)*

smashing the fpr is a the oldest trick in the book.
Works great. I've got a 5bar i smashed too far if you want some serious extra fuel







for the low low price.


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## OhioBenz (Dec 6, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (mrkrad)*


_Quote, originally posted by *mrkrad* »_smashing the fpr is a the oldest trick in the book.
Works great. I've got a 5bar i smashed too far if you want some serious extra fuel







for the low low price.


all it does is compress the spring so the initial pressure is higher


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## GTi_94 (Oct 10, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (GTi_94)*

Didn't even get a chance to do it before some electrical gremlins claimed some key components of my digi2, I'm running a different ecu right now and everytime I start it it runs different, even if you turn it off and the start it right back up...


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## detvw (Jun 5, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (GTi_94)*

Let's keep this going. Great post. Do we have a definitive answer yet as to what works? Andy, we need to give this a shot.


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## username (Mar 27, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (detvw)*


_Quote, originally posted by *detvw* »_Let's keep this going. Great post. Do we have a definitive answer yet as to what works? Andy, we need to give this a shot.

werd http://****************.com/smile/emthup.gif


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## darksideofthemn (Feb 2, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (username)*

Here is some new stuff that is happening. if they get their stuff worked out our fueling problems are solved. 

http://forums.vwvortex.com/zer...85580


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## detvw (Jun 5, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (darksideofthemn)*

I have been following this post as well. I would love to have a chip to resolve my fueling issues. I spent the weekend playing around with my airflow sensor. I really wish there was a reasonably cheap alternative. It's a decent design, but not so good for performance driving imho (ie. acceleration off hard braking/cornering). I did however recieve benefits from mounting it vertical as far as cornering goes. I was having a problem with taking corners before and having my engine bog down, with the sensor mounted vertically, I no longer experience this problem.


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## DanielAdams (Aug 22, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (detvw)*


_Quote, originally posted by *detvw* »_I have been following this post as well. I would love to have a chip to resolve my fueling issues. I spent the weekend playing around with my airflow sensor. I really wish there was a reasonably cheap alternative. It's a decent design, but not so good for performance driving imho (ie. acceleration off hard braking/cornering). I did however recieve benefits from mounting it vertical as far as cornering goes. I was having a problem with taking corners before and having my engine bog down, with the sensor mounted vertically, I no longer experience this problem.

Good point. I neglected to mention it but when I fitted the BMW VAM I too mounted it vertically http://****************.com/smile/emthup.gif


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## xr4tic (Dec 10, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (darksideofthemn)*

After looking at the code, there MIGHT be an easy way to get a MAF up and running.
If you can find a MAF that has a similar voltage curve shape to the stock VAM, it doesn't have to have the same values, but the multiplier between the two should be the same, you might be able to use the air temp sensor as the adjustment.
The only drawback to this, is if the MAF flows a lot more than the stock VAM, then you lose the use of a lot of the airflow table values.
For example, if you can peg the VAM at 5V, but you can only get 3V out of the new MAF, then 40% if the fuel table can't be used.
However, I don't think such a MAF exists
I know the stock VAM out of a Merkur XR4Ti maxes out at roughly 300CFM, and it's should also be a direct plug-in to the VW connector.
I'm not sure if you guys are looking for a bigger meter, or want to eliminate the VAM all together (and replace with MAF or MAP)
They are all doable options, but some flow data from stock meter would be a HUGE help.

_Quote, originally posted by *darksideofthemn* »_Here is some new stuff that is happening. if they get their stuff worked out our fueling problems are solved. 

http://forums.vwvortex.com/zer...85580


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## benzboyracer (Aug 5, 2003)

News from my end- I've found today a Lucas VAM from a Jaguar... surprised me to see Made in Germany printed on the side, so I bought it. Seems to be a Bosch unit in Lucas clothing (cos' there's no way anything made by Lucas is getting fitted to my VW) and was confirmed when I took it apart-- Bosch, or an extremly close copy.
Long story short, I had to transplant the guts of my stock VAM to the Lucas housing. Everything bolted right in without modification, and throttle response is amazing! Next thing is an A/F gauge, and quick.
I'm in the dark about spring tension though; I've got the SNS fuel chip, and the 3.5bar FPR, so I shouldn't be in severe danger of running lean. About 12 clicks loose from the Jaguar stock position seems to work well.


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## xr4tic (Dec 10, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

So how much bigger is the new housing? Pics?

_Quote, originally posted by *benzboyracer* »_News from my end- I've found today a Lucas VAM from a Jaguar... surprised me to see Made in Germany printed on the side, so I bought it. Seems to be a Bosch unit in Lucas clothing (cos' there's no way anything made by Lucas is getting fitted to my VW) and was confirmed when I took it apart-- Bosch, or an extremly close copy.


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (xr4tic)*

Stocker on the left, Jaguar on the right

During surgery... everything from the old unit got switched, except the spring. The new unit also has a weird little counterbalance spring for the door... haven't figured out exactly what that's for yet... will have to play with it.

During disassembly, I found that the screws holding the little resistor board in are VERY difficuly to remove... plan on replacing them, they will get stripped. The Lucas unit also had a larger version of the connector that our stock VAMs use... very strange, and definetly not plug-and-play. They werent even electrically compatible, thus the frankenstien approach.

Just to be perverse, I put the Bosch cap on the Lucas unit... now it's a VAM with an identity crisis.









*edit* Yes, I know the pics suck... it was dark out. New pics will be coming soon as I get sun tommorrow
_Modified by benzboyracer at 8:32 PM 4-16-2004_

_Modified by benzboyracer at 8:37 PM 4-16-2004_


_Modified by benzboyracer at 6:27 PM 10-6-2004_


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## OhioBenz (Dec 6, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

what year Jag?


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (OhioBenz)*

Ohiobenz: Good question. Looked to me like a late-80's, early 90s. It had Ford relays under the hood, so it's likely after the buyout of Jaguar by Ford (forgot the year)


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## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

I finally got my digital camera, so I thought I'd share pics of my BMW AFM setup.








The rest of the pics can be seen @
http://www.hostdub.com/Digiracer





_Modified by Digiracer at 12:39 PM 4-18-2004_


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

Nice pics Digiracer! Wish my camera took as detailed pictures.








More news today- three hours of driving with an A/F meter and I've got it all dialed in. Runs stoich at cruise, goes rich at full throttle, and the power band is much wider.







Hands down, this is the best mod I've done to my car. Now to get all the digifant guys at my local meet hooked up http://****************.com/smile/emthup.gif


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## OhioBenz (Dec 6, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*


_Quote, originally posted by *benzboyracer* »_.... a TT268 hydro cam, Audi 5000 TB, port matched. I've got TT's 2.25 cat-back, dual downpipe, ..... SNS chip ..., and the 3.5bar FPR.....a Jag MAF


So is this the extent of your Mods??
Your tuning with the AF consisted of spring tension on the MAF??


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (OhioBenz)*


_Quote, originally posted by *OhioBenz* »_So is this the extent of your Mods??
Your tuning with the AF consisted of spring tension on the MAF??

Essentially, yep.
Lots of tweaking the spring tension, but I didn't have to replace the spring or anything. I can tweak the car to run leaner if I'd like, or richer, with a click or two on the toothed wheel


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

More news: during some junkyard dissassembly I found that the Denso AFM from the second-gen RX-7s will work, again with an innards swap. Denso would be slightly less foul than a Lucas unit, so I may be picking one up soon.







No BMW units have presented themselves to me though... they've become exceedingly rare. 
I've done some electrical tests in the VAM units, it's not resistance we should be concerned with- it's set up as a voltage-divider, so the ECU sees a varying voltage, not resistance. There's a 5-volt reference signal, and the wiper goes between that and ground, thus providing the varied voltage. That in mind, I've located a GM vacuum sensor that seems to have a similar voltage output curve, and this sensor provides less voltage with less pressure. The next foray into the yards will be to get one of these.








*edit* The aforementioned vacuum sensor is also known as a 1-bar MAP... darn GM and their semantics. 
*edit* Another, more perverse idea, would be to jerry-rig a TPS to send a varying voltage to the ecu... essentially it would be an electronic carb at that point... just dial in your A/F ratio and go.









_Modified by benzboyracer at 9:32 PM 4-20-2004_


_Modified by benzboyracer at 3:28 PM 4-21-2004_


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## eldo (Jul 26, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

wow. you'll have to keep us posted as to whether the GM vacuum sensor works. THAT WOULD BE AWESOME.


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## xr4tic (Dec 10, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

???
Why would you want more voltage with less pressure?
In terms of speed density, at idle, you will see vacuum, and with the exception of decelleration, it will be the lowest pressure the ECU would see. With the VAM, at idle, you have low voltage.
So if you want to use a MAP sensor in place of the VAM, then you want less voltage with less pressure (less pressure = more vacuum)
A 1-bar map sensor will have 0V = 29.92 inHg (-14.7psi), and 5V = 0 inHg (0psi), and is pretty much linear, unlike a VAM, MAF, etc.
One nice thing about speed density though, is that injector on-time is directly related to manifold pressure/vacuum. RPM is only used to compensate for VE losses.


_Quote, originally posted by *benzboyracer* »_ That in mind, I've located a GM vacuum sensor that seems to have a similar voltage output curve, and unlike a MAP sensor, (which has the opposite curve we need: less voltage with less pressure) this vacuum sensor provides more voltage with less pressure. The next foray into the yards will be to get one of these.


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## benzboyracer (Aug 5, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (xr4tic)*

You're right, xr4tic.. Less voltage & less pressure. Yikes, looks like I had things backwards... that's what I get for a beer-fueled late-nite post. I need to stop doing that.








But as for the VAM not being linear, I know it has steps in the output, but those steps are still reasonably linear (it's a voltage divider, after all). I'm banking on the fact that the ECU will be able to make sense of the voltage regardless- it might require some tuning with a small vacuum bleed before the map sensor, or a couple asjustable pots to fine-tune the output signal. Bottom line is it really seems doable- most likely a pull-up or pull-down resistor would be needed to make it idle, but beyond that I can't see any other problems.


_Modified by benzboyracer at 3:49 PM 4-21-2004_


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## xr4tic (Dec 10, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (benzboyracer)*

Just to give you an idea of what the curves should look like:
These are the curves from a Merkur XR4Ti and a Ford SVO/Turbo Coupe (larger curve)








The numbers on the left are CFM, voltage on the bottom.
These feed a turbocharged 2.3, so they should be more than enough for a NA 1.8 or 2.0








I've got a XR4Ti VAM up at my parent's place, I just haven't had time to go get it to see how well it would work.


_Modified by xr4tic at 8:22 PM 4-21-2004_


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## pfcs1 (Jun 7, 2003)

hi John-consider this: @idle, give WOT and VAM goes to about 40% signal while MAP goes 100%; @6000, WOT: both give 100%. Major chip tuning reqd, maybe different logic. You can remove MAP sensor from DIgi I box and run load and ref legs to appropriate 25 pin locations so the VAM signals the box (some other wiring changes needed) and it'll sorta run. Also, if you open a digi II box, there's a provision on the board to mount a MAP sensor??? why? what are the possibilities?


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## benzboyracer (Aug 5, 2003)

*Re: (pfcs1)*

Some further research: if the curve above is indicative of the output of the VAM, then all we'd need to simulate that would be an R/C (resistor-capacitor) network on the output of the MAP sensor. Should be cake








On the other hand, the ECU may very well make sense of the map output directly- infact, the only problem I forsee is a rich condition on sudden accelleration: not anything particularly bad.
In other news, there are some GM and Ford MAF (hotwire-style, but don't use a hot wire... some kind of film) that have 5v analog outputs as well. Given that LH-jetronic (which uses these MAFs) is a kissing cousin to L-jetronic, (Digifant, essentially) making those work shouldn't be hard at all... possibly even as simple as plug-in.
Ever researching....
See here for info on R/C networks: http://people.sinclair.edu/nic...2.htm
http://www.oz.net/~coilgun/the...g.htm



_Modified by benzboyracer at 1:18 PM 4-22-2004_


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## xr4tic (Dec 10, 2001)

*Re: (pfcs1)*

Yeah, I'm aware of that, I'm not 100% sure the proper changes could be made to the ECU. We could make changes to the fuel table to get it to work properly, but ignition is handled by another processor inside the ECU, and I'm not sure if it's crackable. Working on it though








So we could definately get the fuel side sorted out, but the ignition side might not be optimum.


_Quote, originally posted by *pfcs1* »_hi John-consider this: @idle, give WOT and VAM goes to about 40% signal while MAP goes 100%; @6000, WOT: both give 100%. Major chip tuning reqd, maybe different logic. You can remove MAP sensor from DIgi I box and run load and ref legs to appropriate 25 pin locations so the VAM signals the box (some other wiring changes needed) and it'll sorta run. Also, if you open a digi II box, there's a provision on the board to mount a MAP sensor??? why? what are the possibilities?


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## scottamus36 (Jun 13, 2002)

Didn't we have a great solution with the 535 AFM's.
If current supply on these is short, why don't we find someone to pop hoods and "liberate" them?
Should I blow in a call to my homies and paisans?


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## benzboyracer (Aug 5, 2003)

*Re: (scottamus36)*

Scott: The 535 AFM is a great solution- but that project's done







Making a MAP or MAF work is just fun, that's all


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## scottamus36 (Jun 13, 2002)

Oh, to be young again!!! [staying tuned]


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## xr4tic (Dec 10, 2001)

*Re: (benzboyracer)*

The difference between 2V and 5V at 3000RPM is 300% more fuel.
So if you're cruising at 3000 RPM, and floor it, it would dump ~3x as much fuel in. I don't see the car running all that well with that much fuel.
I think some of the GM MAFs are frequency based. The Ford Mustang MAF is a hot-wire type, and has a similar curve to the VAMs I posted above, it's a little lower in the middle, and higher at the ends. Like I posted above, a pot could be put in place of the air temp sensor, and you could adjust the whole curve up/down easily enough.
I've got a Ford Mustang MAF on my XR4Ti, which is L-Jetronic, just a lot more advanced than Digi II (which is strange, since the XR was made in the mid 80s)

_Quote, originally posted by *benzboyracer* »_
On the other hand, the ECU may very well make sense of the map output directly- infact, the only problem I forsee is a rich condition on sudden accelleration: not anything particularly bad.
In other news, there are some GM and Ford MAF (hotwire-style, but don't use a hot wire... some kind of film) that have 5v analog outputs as well. Given that LH-jetronic (which uses these MAFs) is a kissing cousin to L-jetronic, (Digifant, essentially) making those work shouldn't be hard at all... possibly even as simple as plug-in.
Ever researching....


----------



## benzboyracer (Aug 5, 2003)

*Re: (xr4tic)*

xr4tic: What are you basing your MAP curves on? A 1-bar unit? A 2-bar unit? Why would the MAP be giving a 5v signal @ 3000RPM? Or are you speaking of the voltage swing from accelleration?
Just thinking out loud here, couldn't that be compensated for by a longer length of hose, or perhaps a bleed-off, or a restrictor? I know for a fact that the Digi1 system is dependant on the length of its MAP hose.... maybe they did something similar. 
Or, like I mentioned above, an R/C network could create a voltage curve that's more like what the ECU's expecting. Just a tiny value capacitor that (relatively speaking) slowly ramps up the voltage.
Most GM MAFs are frequency based- but there's a couple that are analog, used on the 5.0 and 5.7 motors I believe.... don't have the info here with me at the moment... as I remember though, they don't use the hot-wire design.
BTW, I like the idea of swapping a pot for the temp sensor... anything that makes for tunability I'm up for. http://****************.com/smile/emthup.gif












_Modified by benzboyracer at 6:38 PM 4-22-2004_


----------



## benzboyracer (Aug 5, 2003)

*Re: (benzboyracer)*

Here's some more good info: http://www.autoshop101.com/forms/h34.pdf
There's a nice graph of a VAM output as well... looks strangely linear, and seems to be inverted. 
Still researching...


----------



## xr4tic (Dec 10, 2001)

*Re: (benzboyracer)*

Well, a 1-bar MAP sensor would be 0 to 5V, 5V being 0psi (essentially WOT), doesn't really matter what RPM, once you go WOT, your intake pressure will rise to ~0psi (so yes, I was speaking of the voltage swing on accel)
The length of the hose will cause a slight delay in the pressure reading, but I don't think it would be that noticeable, A bleed wouldn't work too well, it might show up as a vacuum leak to the motor, it might help in the midrange, but would hurt upper RPM by not getting a full reading.
The time constant for the R/C curve would be the same no matter what gear your in, so the ramp would be too quick for higher gears, and too slow for lower gears.

_Quote, originally posted by *benzboyracer* »_xr4tic: What are you basing your MAP curves on? A 1-bar unit? A 2-bar unit? Why would the MAP be giving a 5v signal @ 3000RPM? Or are you speaking of the voltage swing from accelleration?
Just thinking out loud here, couldn't that be compensated for by a longer length of hose, or perhaps a bleed-off, or a restrictor? I know for a fact that the Digi1 system is dependant on the length of its MAP hose.... maybe they did something similar. 
Or, like I mentioned above, an R/C network could create a voltage curve that's more like what the ECU's expecting. Just a tiny value capacitor that (relatively speaking) slowly ramps up the voltage.
Most GM MAFs are frequency based- but there's a couple that are analog, used on the 5.0 and 5.7 motors I believe.... don't have the info here with me at the moment... as I remember though, they don't use the hot-wire design.
BTW, I like the idea of swapping a pot for the temp sensor... anything that makes for tunability I'm up for. http://****************.com/smile/emthup.gif


----------



## benzboyracer (Aug 5, 2003)

*Re: (xr4tic)*

Hmm... so the only option would be to reprogram the ECU with different fueling maps? 
I guess working on a MAF conversion will prolly work out better then... *sigh* 

A







for xr4tic for his excellent advice and graphs.


----------



## scandalous (Jan 4, 2003)

*Re: (benzboyracer)*


_Quote, originally posted by *benzboyracer* »_Hmm... so the only option would be to reprogram the ECU with different fueling maps? 
I guess working on a MAF conversion will prolly work out better then... *sigh* 

A







for xr4tic for his excellent advice and graphs.

Well...... After a few hours of screwing around with my car this morning I have a running/driving stock digiII car using the GM 1 bar MAP wired in place of the VAM.








Wired in a 10k pot to the output of the MAP and picked up a needle valve at Home Depot to put inline from the Vacuum source. Fooled around with both for a bit and low and behold, it runs and drives.
Drove around the neighborhood a bit and everything seems well. But dyno says overall power is about the same, but throttle response is a night and day difference. http://****************.com/smile/emthup.gif 
Far from ideal at this point and who knows what can be done with it, but dammit Jim it DOES actually work.
Gonna go run some errands to get more driving time and will report back later today. Maybe even a small video of the beast in action if I'm motivated.








[edited to spell butt right]


_Modified by scandalous at 11:28 AM 4-25-2004_


----------



## OhioBenz (Dec 6, 2001)

thats awesome!!!
Since there's a bunch of Digi2 gurus here - let me ask a question that is frustrating me on my 90 GL..the car runs great but a little rich (No AF - black tailpipe) as soon as I plug in the (new) O2 sensor it runs like crap, dies at idle, less power in upper bands! We replaced the o2 sensor cos it was all busted from PO, cleaned the VAM, checked fuel pressure, replaced the blue temp sensor - all to no avail - any suggestions????


----------



## xr4tic (Dec 10, 2001)

*Re: (OhioBenz)*

My best guess is a grounding problem, or corrosion/bad connection.
Bust out the ohmmeter, and check the resistance from the O2 connector signal wire to the O2 pin on the ECU (not sure which one it is)
Do the same from the O2 sensor body and the ECU ground.
I think there is also a ground connection to the valve cover, I think it's just for shielding, but make sure it's good as well.

_Quote, originally posted by *OhioBenz* »_
Since there's a bunch of Digi2 gurus here - let me ask a question that is frustrating me on my 90 GL..the car runs great but a little rich (No AF - black tailpipe) as soon as I plug in the (new) O2 sensor it runs like crap, dies at idle, less power in upper bands! We replaced the o2 sensor cos it was all busted from PO, cleaned the VAM, checked fuel pressure, replaced the blue temp sensor - all to no avail - any suggestions????


----------



## benzboyracer (Aug 5, 2003)

*Re: (scandalous)*

Cool deal Scandalous! I'm going to have to play with it some more now. Guess I'm going to the Rat shack and Home Despot tomorrow.







I couldn't get mine to idle well... if I revved it would stall out, and it ran sick rich... grey smoke out the tailpipe. Needle and a 10k pot? How's the pot wired? Voltage divider?
In the interim, I played with the MAF from a Nissan 200SX (95-98ish). The voltages on my girlfriends's 200SX were right around what we need, but that's her car's idle airflow. Trying to convince her that I won't blow it up if I take it out of her car and test it in mine.


----------



## scandalous (Jan 4, 2003)

*Re: (benzboyracer)*


_Quote, originally posted by *benzboyracer* »_Cool deal Scandalous! I'm going to have to play with it some more now. Guess I'm going to the Rat shack and Home Despot tomorrow.







I couldn't get mine to idle well... if I revved it would stall out, and it ran sick rich... grey smoke out the tailpipe. Needle and a 10k pot? How's the pot wired? Voltage divider?
In the interim, I played with the MAF from a Nissan 200SX (95-98ish). The voltages on my girlfriends's 200SX were right around what we need, but that's her car's idle airflow. Trying to convince her that I won't blow it up if I take it out of her car and test it in mine.









Pot is wired as a voltage divider. Just had to trim the voltage a hair and it made a BIG difference. Also, you were right about the length of vacuum hose from the source. I added another 2' to the length and that helped with the off idle response.
Still running really rich, but not much more so than it was with the VAM. May throw my stock digi injectors back in and see if that helps.
Also am going to throw together a proper harness with some test ports and get a vacuum guage so I can view voltage vs. rpm vs vacuum and try to make some sense of what's going on in realtime. It's 







time soon ...
Oh yeah, took it out on the freeway drove about 25 miles and ran some errands with no problems at all.
I'll take a bit of video of it in a bit and if I can find someone who can host it for me I'll put it up..



_Modified by scandalous at 4:21 PM 4-25-2004_


----------



## xr4tic (Dec 10, 2001)

*Re: (scandalous)*

Sweet!
Did the needle valve actually do anything, or was it mainly the pot that made the difference?

_Quote, originally posted by *scandalous* »_
Wired in a 10k pot to the output of the MAP and picked up a needle valve at Home Depot to put inline from the Vacuum source. Fooled around with both for a bit and low and behold, it runs and drives.
Drove around the neighborhood a bit and everything seems well. But dyno says overall power is about the same, but throttle response is a night and day difference. http://****************.com/smile/emthup.gif


----------



## scandalous (Jan 4, 2003)

*Re: (xr4tic)*

Needle valve did very little if anything. It may have added a bit of resistance. I was looking for a "ball" type valve as I think that would work better.
It's all about the pot. Also, I took all vacuum hoses/ISV off and plugged the holes. Pulling vacuum from the larger port on the backside of the throttle body.


----------



## scandalous (Jan 4, 2003)

*Re: (scandalous)*

If there is anyone here that has the space/bandwith to host a 15mb vid, let me know and I'll send it to you.


----------



## scandalous (Jan 4, 2003)

*Re: (scandalous)*

Wired in a 20k pot to replace the ITS yesterday (wasn't even using it before) in an attempt to lean out the mixture.
The stock digi sensor read 1990 ohms at about 60 deg f and output right around 1 volt. Set the pot to put out 1 volt and fired it up. Idled about the same as before, but as soon as I hit the throttle it just bogged out. With the pot outputting 2.5 volts, it idled much better and a little leaner (still super rich), but it wouldn't rev at all, just bogged out with any throttle. 
Thought for sure that the pot in place of the ITS would help lean it out, but no dice.


----------



## xr4tic (Dec 10, 2001)

*Re: (scandalous)*

60 Degrees = 1 Volt? As the temps go down, the voltage should increase (low temps = high resistance = more voltage)
60 degrees should be on the low end of the scale, I would expect to see ~3.5 Volts or so. I'll check mine tonight and see what I get.
As the Voltage decreases, the ECU should lean it out. Which pins are you measuring the voltage at? Pins 1 and 4 should be the air temp, if you measure 1 and 3, you'll get the opposite (1V instead of 4V, etc)


_Quote, originally posted by *scandalous* »_
The stock digi sensor read 1990 ohms at about 60 deg f and output right around 1 volt. Set the pot to put out 1 volt and fired it up. Idled about the same as before, but as soon as I hit the throttle it just bogged out. With the pot outputting 2.5 volts, it idled much better and a little leaner (still super rich), but it wouldn't rev at all, just bogged out with any throttle.


----------



## xr4tic (Dec 10, 2001)

*Re: (xr4tic)*

This is the Air Temp transfer function from the Merkur XR4Ti VAM. 
It should be the same (key word = should)


----------



## scandalous (Jan 4, 2003)

*Re: (xr4tic)*

Hmmmm....
Totally possible I was on on the wrong pin when I was taking readings from my VAM. The resistance did roughly match up to the Bentley.


----------



## Pinto (Nov 4, 2003)

*Re: (scandalous)*

Sweet Finally that the 535 i had sitting on my lot for parts can go to some good use "customer put a hole in the block didn't want to fix it gave it to me for free"


----------



## AV_Dub (Apr 7, 2004)

*Re: (Pinto)*

Bump for conclusions? yay or nay? You guys get locked up for exceeding 150mph?


----------



## MBRACKLIFFE (Jan 17, 2003)

*Re: (AV_Dub)*

I just had a thought that I wanted to throw out there... since the stock VAM work's by the intake air opening up the flap inside. ie: more air = flap open farther = more fuel I thought that we might be able to open up the VAM take out the part that tracks the position of the flap and attach it directly to the throttle cable. In essence we would be converting a VAM to a TPS and with some built in adjustability we could even tune our AF ratio very easily and have absolutly no intake restriction. As long as the throw of the throttle cable was matched to the correct travel of the VAM I don't see any potential problem's. The other sensor's in the VAM could even be adapted to remain in the intake tract. Now if I only had a spare VAM to play with I could test my theory. Let me know what you think.


----------



## scandalous (Jan 4, 2003)

*Re: (MBRACKLIFFE)*


_Quote, originally posted by *MBRACKLIFFE* »_I just had a thought that I wanted to throw out there... since the stock VAM work's by the intake air opening up the flap inside. ie: more air = flap open farther = more fuel I thought that we might be able to open up the VAM take out the part that tracks the position of the flap and attach it directly to the throttle cable. In essence we would be converting a VAM to a TPS and with some built in adjustability we could even tune our AF ratio very easily and have absolutly no intake restriction. As long as the throw of the throttle cable was matched to the correct travel of the VAM I don't see any potential problem's. The other sensor's in the VAM could even be adapted to remain in the intake tract. Now if I only had a spare VAM to play with I could test my theory. Let me know what you think.

Sounds totally feasible.http://****************.com/smile/emthup.gif 
All you really need though is any rotary position sensor that will give you 0-5 volts when a baseline of 5v is applied. Might be easier than trying to attach the VAM guts to the side of your intake somehow.


----------



## AV_Dub (Apr 7, 2004)

*Re: (MBRACKLIFFE)*

I think denser or colder air opens it farther than thin or hot air... at the same velocity? Not sure.
Might be worth a try, but I was wondering if running two airmeters side by side using resistors to half the voltage from each? LOL.... Muahahahaha! , maybe not...


----------



## scandalous (Jan 4, 2003)

*Re: (AV_Dub)*


_Quote, originally posted by *AV_Dub* »_I think denser or colder air opens it farther than thin or hot air... at the same velocity? Not sure.
Might be worth a try, but I was wondering if running two airmeters side by side using resistors to half the voltage from each? LOL.... Muahahahaha! , maybe not...

So simple, yet so easily doable. http://****************.com/smile/emthup.gif 
Awsome idea!


----------



## AV_Dub (Apr 7, 2004)

*Re: (scandalous)*

Mount the rotary on the throttle body.. Would be sweet! in fact, do away with the whole freekin airbox, and make a throttle body to do it all.


----------



## AV_Dub (Apr 7, 2004)

*Re: (scandalous)*

Could make for some serious twin turbo action...


----------



## scandalous (Jan 4, 2003)

*Re: (AV_Dub)*


_Quote, originally posted by *AV_Dub* »_Mount the rotary on the throttle body.. Would be sweet! in fact, do away with the whole freekin airbox, and make a throttle body to do it all.

Had mine running with the MAP with no box and no intake tubing. The sound alone was worth it..
I have video with sound of it. Just no space/bandwidth to host it.


_Modified by scandalous at 6:01 PM 5-2-2004_


----------



## AV_Dub (Apr 7, 2004)

*Re: (scandalous)*

LOL!!! oh thats great!


----------



## AV_Dub (Apr 7, 2004)

*Re: (scandalous)*

Did you just clamp it right on to the throttle body!!!


----------



## AV_Dub (Apr 7, 2004)

*Re: (AV_Dub)*

GREAT SUCKING JETTAS BATMAN!


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## scandalous (Jan 4, 2003)

*Re: (AV_Dub)*


_Quote, originally posted by *AV_Dub* »_Did you just clamp it right on to the throttle body!!!

I just had the MAP lying in my raintray.







No need to attach it to anything, just a hose pulling vacuum and the harness connected to it.


----------



## AV_Dub (Apr 7, 2004)

*Re: (scandalous)*

Bet it sounded like an angry cow!


----------



## AV_Dub (Apr 7, 2004)

*Re: (AV_Dub)*

Use an aluminum flywheel with that setup and you'll scare the Indy guys!


----------



## scandalous (Jan 4, 2003)

*Re: (AV_Dub)*

Ok.. I'm gonna try to find somewhere to put this video up.


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## AV_Dub (Apr 7, 2004)

*Re: (scandalous)*

Right on! I'm already sore from laughing...


----------



## AV_Dub (Apr 7, 2004)

*Re: (AV_Dub)*

The ultimate imitation quadrajet..


----------



## AV_Dub (Apr 7, 2004)

*Re: (AV_Dub)*

I think I just figured out one of the reasons for the digi lag... Airmeter is way too far from the throttle body! reduce the diameter of the tube that feeds the throttle body and response will improve, although flow potential will drop. clamp the airmeter to the throttle body and see what happens. (Get rid of the tube between them) Might need to actually tighten the spring on the airmeter to stop it from slamming open when you floor it though.. or maybe that would be a good thing? WoooHooo! response of a double pumper! or not... I wonder if VW designed it that way for back-fire concerns? Back-fires are allways a thrill in my cis porsche.

_Modified by AV_Dub at 2:27 AM 5-3-2004_

_Modified by AV_Dub at 2:29 AM 5-3-2004_


_Modified by AV_Dub at 2:34 AM 5-3-2004_


----------



## OhioBenz (Dec 6, 2001)

*Re: (AV_Dub)*

intakes are designed to deal with the harmonics that result in the air stream when the inrush of air that meets a closed intake valve....
So when you move the Af right to the TB, its gonna be bouncing like crazy!!


----------



## AV_Dub (Apr 7, 2004)

*Re: (OhioBenz)*

Yah, Kinda thought it might be a problem... That's why I suggested increasing the spring pressure... How about fluid damped? or the pin that hinges it could be moved towards the center of the flap giving it a bit more leverage without increasing spring tension... semi butterfly valve, but not so much as to prevent it's opening by suction..
Just goofin around...

_Modified by AV_Dub at 2:40 AM 5-3-2004_


_Modified by AV_Dub at 2:42 AM 5-3-2004_


----------



## AV_Dub (Apr 7, 2004)

*Re: (AV_Dub)*

Hmmmm... there must be some way to cancel the pulses other than a big honkin long runner..
A chamber in the intake manifold that could be spring tention tuned, or large rubber diaphram that will soak the pulses.. But it would have to be pretty large so the pulses would choose it as the path of least resistance.


_Modified by AV_Dub at 2:50 AM 5-3-2004_


----------



## OhioBenz (Dec 6, 2001)

*Re: (AV_Dub)*

all that would end up getting the lag back in....


----------



## scandalous (Jan 4, 2003)

*Re: (AV_Dub)*


_Quote, originally posted by *AV_Dub* »_Right on! I'm already sore from laughing...

hehe...
Get ready for some more..








Vid is uploading to some free webspace. We'll see if it actually works.


----------



## AV_Dub (Apr 7, 2004)

*Re: (scandalous)*

I GOT to hear this.


----------



## AV_Dub (Apr 7, 2004)

*Re: (AV_Dub)*

I bet i'm not the ONLY one who ever thought about pulse cancellation possibilities...
Know if anyone has been successful?


----------



## scandalous (Jan 4, 2003)

*Re: (AV_Dub)*

Arggh. My vid is 15 megs. Waaaayyy over the file size limit for any free hosting.


----------



## AV_Dub (Apr 7, 2004)

*Re: (scandalous)*

Bummer,,, all good though!


----------



## xr4tic (Dec 10, 2001)

*Re: (MBRACKLIFFE)*

In essence, a TPS system would be like a MAP.
Idle = full vacuum
Part Throttle = partial vacuum
WOT = no vacuum
But it's not going to increase vs. RPM like a VAM would.
The only thing that will act like a VAM, is a VAM (or a MAF) You can make a MAP or TPS act like a VAM at a few points, but it won't cover the full range.

_Quote, originally posted by *MBRACKLIFFE* »_ In essence we would be converting a VAM to a TPS and with some built in adjustability we could even tune our AF ratio very easily and have absolutly no intake restriction.


----------



## AV_Dub (Apr 7, 2004)

*Re: (xr4tic)*

Any off the wall ideas to mod this thing? We're obviously thinking WAY above the norm here







(or hopelessly below the norm)


----------



## OhioBenz (Dec 6, 2001)

*Re: (AV_Dub)*

SIGH, i realize that German engineers live by the motto that "if simple is good, then complicated is always better" but some things you just can't get around.
There's pro's and con's to every system - what you gain in one you may lose somewhere else.
The only REAL solution is stand-alone tuned specifically for your car.
Anything else is same as search for the Holy Grail, Fountain of Youth or a perpetual motion machine.......
We can surely improve on the basic system - most likely by different components (read more tuned to your engine) doing the same job, or rewritten maps.


----------



## AV_Dub (Apr 7, 2004)

*Re: (OhioBenz)*

So why are you guys even bothering to experiment with a BMW airmeter to improve performance? We'er just having a little fun with this. Maybe some guy somewhere was joking around and said: "I know, we can put an air pump on the thing." response: "Your nuts dude, just leave it alone. It's fine the way it is."
Turbo anyone?
So which BMW airmeter ended up working? The 535? Anything needed other than swapping guts? was mapping necessary? spring tension adjustments?
Were just trying to get more fuel and air into this sucker. 


_Modified by AV_Dub at 4:45 AM 5-3-2004_


----------



## Assimlatr (Dec 16, 2003)

*Re: (scandalous) MAP Voltage Adjustment*

I was thinking...a while back I saw this adjustment circuit for a MAP that you could fine tune at this link: http://www.autospeed.com/cms/a...8&P=5.
Would this help it at all?


----------



## AV_Dub (Apr 7, 2004)

*Re: (scandalous) MAP Voltage Adjustment (Assimlatr)*

Yes, that will probably work! I think someone here is attempting that as we speak.. The only other thing I would add is maybe a pot to the oxygen sensor voltage, to make leaning back down adjustable. It could be "triggered" with an extra momentary contact switch mounted on the full throttle switch I guess, (or a second full throttle switch)and would make full throttle ratio a little more adjustable. and maybe safer too. That way, The O2 sensor will only fully lean the system back down under less than full load. LOL... it would even pass smog.
It seems like after installing pots on the airmeter, the only other variable is the oxygen sensor! (If you want to keep the chip you currently have) A performance chip would be better though, if it addresses timing also...
The pots in the article could be used to not only compensate for bigger injectors, but possibly for a bigger airmeter as well. But the bigger airmeter needs to be identical voltage wise to a stocker. So we swap guts from a stocker, and adjust spring tension to get it close. Or... Lighten the bigger flapper door to equal the weight of the stocker, and use the stockers spring at stock setting.
What do you think? 
This could all be done for say... 20 bucks, a junk yard airmeter, and junk yard injectors.
Good find!












_Modified by AV_Dub at 9:13 AM 5-3-2004_


----------



## username (Mar 27, 2001)

*Re: (AV_Dub)*


_Quote, originally posted by *AV_Dub* »_Use an aluminum flywheel with that setup and you'll scare the Indy guys!

hahaha http://****************.com/smile/emthup.gif
one of these days i'm going to try out some of this stuff. i do have an AMS chip in the car now...once the ABA block and ported head go in i think it will be time
i just wish i could help out on the electronic stuff, but alas...electricity=magic in my head


----------



## AV_Dub (Apr 7, 2004)

*Re: (username)*

Yah, the mod for the O2 sensor seems like it would work in theory, but I got afunny feeling there will be more to the electrical end of it than just putting a pot in there... I think someone tried a resistor instead. Oh well, TO THE JUNKYARD!!!


----------



## Assimlatr (Dec 16, 2003)

*Re: (AV_Dub)*


_Quote, originally posted by *AV_Dub* »_So we swap guts from a stocker, and adjust spring tension to get it close. Or... Lighten the bigger flapper door to equal the weight of the stocker, and use the stockers spring at stock setting.

Your not going to believe it







, but I have actually done a swap from my stocker to a 2.3L out of a Thunderbird TC. I bought a spring tension scale from a local school supply store to calibrate it. I figured that there would be 70% less airflow coming across the flapper to calibrate at about 1LB.
All this goes on a solid lifter G-grind Cali Digfant-I w/ 12.5:1 comp. It seems to run great. I am running an AMS chip and g-60 injectors so I had not thought about the O2...interesting







. Performance on off idle seems to be a bit slower, but once it hits about 3000...look out cause that engine is going to 6K in no time flat w/ the first 3 gears all hitting 7K.
One thing I might suggest as a factor would be the knock sensor cause that engine is gonna keep sucking in more air past the maximum of where the stocker would max out. So way up high it leans out and the knock sensor stops ya. (Mine is in 4th gear at about 6700, but will pull 5th to 5750). I think that is where more fuel pressure comes in.


----------



## AV_Dub (Apr 7, 2004)

*Re: (Assimlatr)*

Kewl... it works! what a kick to mod something in an "unusual manner" and have it actually work! a ford airmeter??? LOL, now i've heard everything! Please try it with at least a 944 porsche meter??? bragging rights are awaiting.








Nice... As far as the knock sensor, if you up the fuel pressure a little with those injectors you shouldn't have any problem with leaning out and knocking. unless the O2 sensor takes over for some reason.. or with 12.5:1's you better be running race fuel, or AVgas. But maybe the mod for the the O2 sensor will complete your mods! Let me know if you try it?
Kudos! head for the dyno!!!


----------



## docspeed1 (Apr 26, 2002)

*Re: (Assimlatr)*

Interesting...Is the T-bird unit a direct plug'n play like the BMW unit, and far as the harness connectors are concerned?


----------



## Assimlatr (Dec 16, 2003)

*Re: (docspeed1)*

When I had the original guts in the unit...the T-Bird was also direct plug and play. Did have a little different resistance curve. It was great when I had just the stock cam as it would make the intake take on a whistle that sounded like a B/O valve.
Turned a couple heads


----------



## docspeed1 (Apr 26, 2002)

*Re: (Assimlatr)*

I know most of you guys have moved past the whole big VAM idea, but anybody know if a VAM off a 944 would work with the stock wiring harness? It looks similar from pictures I can see. Ebay is littered with them for cheap.


----------



## OhioBenz (Dec 6, 2001)

*Re: (docspeed1)*

can they flow more air?


----------



## AV_Dub (Apr 7, 2004)

*Re: (OhioBenz)*

Well, the 944 is a 2.5L (2479cc) It's probably a big enough airmeter for anything you could throw at it 4 cylinder-wise...


----------



## xr4tic (Dec 10, 2001)

*Re: (AV_Dub)*

And the 2.3L Turbo in the Merkur XR4Ti, Mustang SVO, and Ford Turbo Coupe should flow even more


----------



## CABBY2L16V (Oct 19, 1999)

*Re: (AV_Dub)*

I bought a porsche 944 afm last month & it is a direct plug & play with my 92 digifant cabster. Not only that, all the mounting holes on the air box line up perfectly. So no mods were needed to install it, just R&R. I haven't driven the car yet with this set up, but it idles & revs much better than it did with the stock one. Once my 3.5 bar fpr gets here, I'll hopefully have time to take it for a spin.
The part # for my 944 afm is:
0 280 202 064


----------



## docspeed1 (Apr 26, 2002)

*Re: (CABBY2L16V)*

Thats good info. Is the 944 AFM significantly larger than the stock digi AFM?


----------



## AV_Dub (Apr 7, 2004)

*Re: (CABBY2L16V)*

Ding! Ding Ding! WINNER!!! Congrats!! and thanks for relaying the info. What year 944 is it from? 
Was the electrical connection the same, or did you have to switch plugs?
Kudos!!!


----------



## docspeed1 (Apr 26, 2002)

*Re: (AV_Dub)*


_Quote, originally posted by *AV_Dub* »_Ding! Ding Ding! WINNER!!! Congrats!! and thanks for relaying the info. What year 944 is it from? 
Was the electrical connection the same, or did you have to switch plugs?
Kudos!!!










Don't get so excited! Re-read the post, it will answer your question.


----------



## eurojim (Dec 7, 2003)

*Re: (CABBY2L16V)*

I've been reading this thread and all i have to say is i envy all of you who took this on. you guys did an amazing job. i wish i had the time/patience/brains to do that. but about the 944...ebay has a maf conversion that eliminated the vam...so if the 944 vam works, then this conversion should be able to work as well right? if not, with a little tinkering it should. ony thing is its worth more than some of our cars....ah well. keep up this wicked thread


----------



## AV_Dub (Apr 7, 2004)

*Re: (docspeed1)*

Yah, Sorry, I do get a bit excited... But I re-read the post and it is plug and play! I was just trying to verify the extent of "Plug and Play". A little fine tuning Is probably needed, but I think it's great that the 944 unit "Idles, And revs" a little better than stock, even though he hasn't posted a complete review.
Yes the MAF would work if they have made a mod kit for it. I almost got one of those for my 944 years ago. It cost too much then, and looks like it hasn't come down! My 944 Turbo was outputting close to 300hp with a chip change and a couple other things, so I never bought the big MAF.
COOL! our next search is to find a stocker that used a MAF that is "Plug and Play" swap for our 8v VWs! LOL... just kidding..... eh, Kinda


_Modified by AV_Dub at 5:21 AM 5-7-2004_


----------



## benzboyracer (Aug 5, 2003)

*Re: (AV_Dub)*


_Quote »_COOL! our next search is to find a stocker that used a MAF that is "Plug and Play" swap for our 8v VWs! LOL... just kidding..... eh, Kinda

Nissan 200SX MAF... from '95-'98...


----------



## AV_Dub (Apr 7, 2004)

*Re: (benzboyracer)*

LOL! 
You peeps gonna make a chip & kit for this stuff? Hope so! If you do, please get rid of the REV LIMITER.








There, I feel better now...


----------



## naterkane (Feb 8, 2001)

i can source quite a number of 944 maf's (i'm not kidding!)
if anyone wants one, let me know, and i'll hook it up (not for free since i have to actually go and pull them for you, but damn cheap)
i'll give it a shot myself tomorrow and take some pics of it as well...


----------



## OhioBenz (Dec 6, 2001)

*Re: (naterkane)*


_Quote, originally posted by *naterkane* »_i can source quite a number of 944 maf's (i'm not kidding!)
if anyone wants one, let me know, and i'll hook it up (not for free since i have to actually go and pull them for you, but damn cheap)
i'll give it a shot myself tomorrow and take some pics of it as well...


pm me a price - i'm interested


----------



## AV_Dub (Apr 7, 2004)

*Re: (naterkane)*

One for me! Thanx


----------



## a2-8v-pgh (Aug 16, 2003)

hey guys congradulations, i was looking around at pics yesterday. after pulling my maf to look at the restrictive hole, ive read SOOOO much about. and i was looking at a 944. i looked closely at the pic and said to myself "that looks remarkebly like the 8v maf, i should go find the post on them and mention it." well i came on to do so tonight and its the last thing discussed, so goo dluck and let me know how things go...


----------



## Digiracer (May 5, 2002)

*Re: (a2-8v-pgh)*

Cabby2L16v said the mounting holes on the Porsche 944 are the same, meaning it'll fit in the stock airbox. So that means it doesn't flow anymore air than the OEM unit. 
So what's the point guys?








Some say it revs quicker, just loosen the spring tension on the OEM unit. 
You're paying for the Porsche logo on the plastic cover of the same Bosch AFM.








I'm not trying to sound arrogant here, someone please correct me if I'm wrong.


----------



## xr4tic (Dec 10, 2001)

I just took a look at the VAM unit from my Merkur. On the outside, it's identical. It will bolt right in place of the stock unit no problem.
If you look inside the unit, you can see the Ford unit is slightly bigger, but it's not a huge difference.
I have a feeling the gains people are seeing is because they are tuning the bigger units in. I bet the stock unit would run almost as well if it was tweeked a little, unless of course you are maxing it out. If you are, you're probably maxing the stock injectors out as well, so it might be an upgrade along with larger injectors (or FPR) without having to mess with a chip.
I think the ideal solution is a MAP sensor.


----------



## naterkane (Feb 8, 2001)

for whoever would like a 944 MAF
just send me an email to [email protected] w/ your info...
i'm going to ask $50 plus shipping. i think that's fair.
first come first serve, i don't know how many i have left in my super secret porsche and audi yard.


----------



## OhioBenz (Dec 6, 2001)

*Re: (naterkane)*

can you post a pic of them side by side?


----------



## Zipper (Oct 28, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Ok its a dump input but did anyone ever consider switching to CIS or CIS-e. I was under the impression it allowed greater air flow and was more tunable. 
If this is true then would it not be easier to just swap in an older EFI system. It also has a stock 5bar fuel pressure where we only have like 2 bar. 
I hope I got my stuff right.
Chris
That being said Ill still take a pic of the 944 air box.


_Modified by Zipper at 10:38 AM 5-12-2004_


----------



## worm68 (Dec 18, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Zipper)*

A










































for all involved in this post. I put the bmw vam on today felt power from bottom to top still haven't tuned it yet putting in afg tomorrow. best mod so far digi 2 16v


----------



## AV_Dub (Apr 7, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (worm68)*

Was wondering if a 16v might like it... Awsome! http://****************.com/smile/emthup.gif


----------



## Assimlatr (Dec 16, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (AV_Dub)*


_Quote, originally posted by *AV_Dub* »_Was wondering if a 16v might like it... Awsome! http://****************.com/smile/emthup.gif 

Oh YES, a buddy and me did a digi1-cali on a 88 16v. Pain in the butt...but fantastic...especially with the TC AFM.


----------



## sloppychicken (Jan 28, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Assimlatr)*


_Quote, originally posted by *Assimlatr* »_
Oh YES, a buddy and me did a digi1-cali on a 88 16v. Pain in the butt...but fantastic...especially with the TC AFM.

I didn't think they made a chip for Digi I Cali


----------



## Assimlatr (Dec 16, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (sloppychicken)*


_Quote, originally posted by *sloppychicken* »_
I didn't think they made a chip for Digi I Cali

AMS made the chip. Not to bad, could be better.


----------



## mrkrad (Nov 9, 2000)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Assimlatr)*

jah not too hard to do cali-digi-1, just need a motor to back the gains.


----------



## 2002maniac (May 3, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (mrkrad)*

Hey Digiracer, more details on your setup please! p/n for the map sensor would be nice. how is it running?


----------



## 2002maniac (May 3, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (2002maniac)*

And for those of you interested in the 944 setup, this would be the next step up








http://cgi.ebay.com/ebaymotors...=WDVW


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (2002maniac)*

My setup has been running great since the day I installed it 2002Maniac. Though I haven't driven the car lately(needs brakes). 
Pics of my setup can be seen on page 7 of this thread. The BMW AFM in the pic apears to be the stock OEM unit, infact it's much larger than the stock peice. It runs really well, almost stocklike until you get into the higher rpms. I'm using a crushed 4.6 bar FPR with stock injectors. I upgraded the piping to 3inch pipe. I ditched all the IAC motor & idle control crap. It's much cleaner & simpler now. The idle is adjusted with the idle screw on the TB now. Mine idles happily around 1000-1100 rpm. (Neuspeed 276 cam) The engine really breathes now, I've hit the 7,000 rpm rev limit in 4th gear. It used to run out of breathe around 5,500 rpm with the OEM Airflow meter. Anymore questions feel free to ask. Daniel Adams is also running the same setup on his 2.1 stroker & with great results too. http://****************.com/smile/emthup.gif 



_Modified by Digiracer at 10:03 PM 7-13-2004_


----------



## 2002maniac (May 3, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

Thanks Digiracer your setup looks sweet!!
Got a question for scandalous, How is your setup running with the 1bar GM MAP sensor? That sensor sends a signal to the ecu depending on vacuum, right? More info please!?! You guys rule!!!


----------



## scandalous (Jan 4, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (2002maniac)*


_Quote, originally posted by *2002maniac* »_Thanks Digiracer your setup looks sweet!!
Got a question for scandalous, How is your setup running with the 1bar GM MAP sensor? That sensor sends a signal to the ecu depending on vacuum, right? More info please!?! You guys rule!!!

Yup, it outputs 0-5 volts depending on the pressure in the intake.
I only ran the GM map for a few days. Back and forth to work, normal daily routine stuff. It ran decent but BRUTALLY rich. 
I'm not sure how well it could actually work. My car runs rich anyway because I'm running bigger than stock injectors and I'm sure that contributed to the problem. Would take someone with more technical knowlege and time than myself to get it working right, although I'm sure it could be done.
I just finished assembling a Megasquirt ECU/relay board and have sourced all the parts to run a Ford EDIS system with it. Also in the process a rebuilding a 1.8 16v that will get bike throttle bodies, working 55+ hours a week and my wife is 4 days past her due date so I haven't really had time to fool around with the GM map lately.








I have a video of the car running with the GM map, but it's 15 megs. Have no webspace to host it and all the free hosting out there seems to allow no more than 5 megs.

IM me your email addy and I'll try to send it to you. It gives a little look at how I had it setup.




_Modified by scandalous at 9:32 PM 5-30-2004_


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (scandalous)*

Hey Scandalous, congrats on your little one.








Did you by chance run an Air/Fuel Ratio gauge on your GM map setup?
I'm just curious as to how rich it was actually running.
Maybe the issue could be solved using smaller 2.0 Injectors(189 cc).
What else have you done to the car? I'm sure if you're running more compression, P&P head, huge cam, more timing etc, the rich issue can be curbed also. 
Can you show us a pic of your setup please?


----------



## scandalous (Jan 4, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*


_Quote, originally posted by *Digiracer* »_ Hey Scandalous, congrats on your little one.








Did you by chance run an Air/Fuel Ratio gauge on your GM map setup?
I'm just curious as to how rich it was actually running.
Maybe the issue could be solved using smaller 2.0 Injectors(189 cc).
What else have you done to the car? I'm sure if you're running more compression, P&P head, huge cam, more timing etc, the rich issue can be curbed also. 
Can you show us a pic of your setup please?

Thanks for the congrats! My daughter was born on thursday night and is perfect in every way.







http://****************.com/smile/emthup.gif 
Didn't have an A/F hooked up, but I'm positive it would have been pegged on rich. Doubt if my narrowband sensor would have been of any real use at all.
Car is bone stock except for 26lb injectors.
A couple of pics. I just had my stuff laying in the raintray. Was pulling vacuum from the larger plug on the back of the throttle body.


----------



## SpoonEngineering (Apr 2, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*


_Quote, originally posted by *Digiracer* »_I finally got my digital camera, so I thought I'd share pics of my BMW AFM setup.








The rest of the pics can be seen @
http://www.hostdub.com/Digiracer
sent you an IM digiracer...

_Modified by Digiracer at 12:39 PM 4-18-2004_


----------



## 2002maniac (May 3, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (SpoonEngineering)*

Hmm, I might have to read up on electronics and give this a try. Whats a pot







I know, I know, I know, If I dont know what a "Pot" is I will probably have no clue and will never be able to do it. But help a newbie out http://****************.com/smile/emthup.gif Heck if I can figure out a Digi2 controlled ABA Crossflow, Im no Idiot(no genious either, it hasnt been hard at all)


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

I want to show you a clear example as to why the stock airflow meter is a huge limiting factory in our quest for Big Digifant II Horsepower. (16Valve Digifant II Guys take notes)
notice how it peaks at only 5,000 rpm? 
It's pathetic considering the mods done to this engine. 
2.0 ABA, Mild P&P RPI Head, 10.3:1, Neuspeed 276 .453 lift/cam, AMS Chip, -ac-pws TT catless exhaust, Supersprint G60 Header
Alittle speculation here, this was a 3rd gear pull, now with the BMW AFM in place I can hit the 7,000 rpm rev limiter in 4th, I'm anticipating my new power peak to be around 6-6,500 rpm. I will try to get back on the dyno soon.









_Modified by Digiracer at 1:38 PM 6-22-2004_

_Modified by Digiracer at 1:44 PM 6-22-2004_


_Modified by Digiracer at 2:03 PM 6-22-2004_


----------



## jamesn67 (Nov 15, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

What set-up are those dyno runs from?


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (jamesn67)*

That was old setup, since then I did the BMW AFM swap, upgraded the intake pipe to 3inch, 3inch K&N cone filter, swapped a 4K trans in, ditched my pvc crap now a homemade breather setup, removed all the IAC/ISV crap, 
Attention: check out my old dyno post on the bottom of page 10, some good info there http://****************.com/smile/emthup.gif


----------



## scottamus36 (Jun 13, 2002)

how bout some new dyno runs?... Where do I send the donation? :>


----------



## naterkane (Feb 8, 2001)

*Re: (Digiracer)*


_Quote, originally posted by *Digiracer* »_ Cabby2L16v said the mounting holes on the Porsche 944 are the same, meaning it'll fit in the stock airbox. So that means it doesn't flow anymore air than the OEM unit. 
So what's the point guys?








Some say it revs quicker, just loosen the spring tension on the OEM unit. 
You're paying for the Porsche logo on the plastic cover of the same Bosch AFM.








I'm not trying to sound arrogant here, someone please correct me if I'm wrong.









there are a few differences between the 944 maf and the 8v one. 
mainly.. spring tension. the 944 maf has a stronger spring. meaning it needs to be backed off about 6-9 clicks to idle well and get good response, but, has more linear resistance, and doesn't flap around like a backed off stock 8v one does. http://****************.com/smile/emthup.gif also, the (airtemp?) sensor inside is lower profile and a different design.
my car doesn't cut (like a low temp rev limiter) anymore like it did with the stock maf. that's a HUGE deal. not that i WANT to redline the car when it's cold, but sometimes it's just annoying as h3ll to try to accellerate with a 2Y tranny and have the fueling get cut at 4500 rpms when it's cold outside.







http://****************.com/smile/emthdown.gif 
no, it won't technically flow more cfms, but it has improved the driveability of the car immensely. i'm considering dumping this motor but keeping my digi2. if i end up doing a digi2 16v instead of just an aba, i will absolutely use the bmw unit.


----------



## Boosted16VGolf (May 21, 2004)

*Re: (naterkane)*

I've been tracking this info for a while now( very interesting). I started to do searches on the BMW 535 meter, and found this link. Maybe it's already been thought about and dismissed, who knows. I thought it might be worth a brief look.
http://www.teamdfl.com/bmw/e28/induction/maf.html


----------



## ewongkaizen (Apr 19, 2002)

*Re: (Boosted16VGolf)*

Sort off topic but possibley relevent....
Toyota uses a "Licensed" version of L-Jetronic on their cars/trucks.
The EFI box has an output that is labeled Vf.
Of course - no factory manual will tell you what the Vf signal is used for.
What some on a Toyota list(s) have found is that the Vf is in fact the "offset trim from the base map"....
In other words, the Vf voltage will tell you what the EFI computer is doing to "compensate" for its initial injector pulse width versus what the 02 sensor tells it.
So it ya slap a bigger air flow meter on there and the car poorly you can tell if the EFI thinks its too rich and its attempting to lean it out or vice versa - very useful for tuning the spring tension.
So - does the VW have a similar output fromthe EFI?


----------



## 603K1D (Jun 19, 2002)

*Re: (ewongkaizen)*

alright so the second palmbeacher is getting into this mess now
i have aquired a 633i vam yet i have no fpr or chip
before i install these parts i guess id like to start solving the problem of 
why does my car run like crap
most people say cuz its digi2
prognosis: intermitant loss of what feels like a cylinder
brutal loss of power under acceleration 
and under general cruizing it sometimes seems to just shut off
any ideas?


----------



## AV_Dub (Apr 7, 2004)

*Re: (603K1D)*

I'd start by check all wiring in engine compartment for shorts... mine did that and drove me crazy for months till I found it. intermitent problems=


----------



## 603K1D (Jun 19, 2002)

*Re: (AV_Dub)*

shorts defintiely suck 
i would have no idea as to where to start looking because when i wiggle wires it doesnt change the state of running 








i guess ill figure it out sometime


----------



## OhioBenz (Dec 6, 2001)

*Re: (603K1D)*

if u need to clean the connectors - use Lysol Toilet Bowl Cleaner - the squirt kind.. then rinse w water & dry


----------



## Digiracer (May 5, 2002)

Not to be a ****, but aren't we getting alittle off topic here? 
Props to you anyway, for atleast keeping this topic on the board & visable.


----------



## jamaicula (Jul 10, 2002)

*Re: (Digiracer)*

Which BMW do you take the afm from? I have a 16v digi II with an AMS chip.


----------



## Digiracer (May 5, 2002)

*Re: (jamaicula)*


_Quote, originally posted by *jamaicula* »_Which BMW do you take the afm from? I have a 16v digi II with an AMS chip.

Ask & you shall recieve (I keep saying that)
http://forums.vwvortex.com/zerothread?id=1019859
scroll down to the bottom http://****************.com/smile/emthup.gif


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

I think you guys will find this cool.








http://forums.vwvortex.com/zerothread?id=1508317
Hey where the heck is Daniel Adams?????
He's a respected founder on this project & he's missing out on the fun here.
Gotta keep a good thing going...........BUMP



_Modified by Digiracer at 3:09 AM 7-24-2004_


----------



## 603K1D (Jun 19, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

finally figured out what my running prob was 
i had a bad intank pump and a hole in the coupler between it and the sending unit 
when we went to check the fuel pressure the thing went off like a super soaker
there was tons of air in the lines all pressurized by the undercar pump
runs good now
time for some modding http://****************.com/smile/emthup.gif


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (603K1D)*

Update on my Golf/BMW AFM/CAI Setup:
Installed Thermotec Heat Wrap on the Header & Thermotec Tape on the fuel line inside the engine compartment.
Advanced the ignition timing to 30 degrees @ idle from 25 degrees.
Switched to straight water + Redline Water Wetter. (so much cooler now) 
Port matched my intake manifold to the head, (gasket matched it).
Their was a nice 1/16th-an 1/8th ridge on all 4 runners. Hopefully picked up afew CFM there lol.
Removed the stock 20or 21lb injectors & 4.6 bar FPR.
Replaced them with 24lb Accel Injectors & put the 3.5bar FPR back in. It seemed to run too rich so I put the stock 3bar back in. It's near perfect where it's at now. Plenty of fuel, no ping under load, (it was in the upper 90's here today with lots of humidity off the lake)http://****************.com/smile/emthup.gif (normally would ping under WOT testing)
I realize I could have went with slightly smaller injectors, but I'll need the extra fuel later for my worked Crossflow Head project.
I have an adjustable, rising rate FPR on the way, it'll be perfect & ready for the dyno finally.


----------



## vwjunkie42 (Jan 17, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

i havent been folowig the tread, but i have looked it over. i am also looking for something for my digi2 16v. has anyone looked into Split Second's MAF kit. thay make them for BMW so if the bmw one will work for us, than so should the spitsec kit.
http://www.splitsec.com/index.html
look in products, MAF kits.
check it out i could be the answer to our prayers








nik







one for the road


----------



## 2002maniac (May 3, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (vwjunkie42)*

if you look through every one of these 11 pages youll see someone allready did it.







Im not sure if he ever posted results though.


----------



## dacolino (Jun 1, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (2002maniac)*

This is the kind of thread i like to see....ive seen it before but never read it....so finally i sat down and read this WHOLE thread for about 2 hours or so. awesome thread HUGE BUMP for anyone who has done this swap and has provided so much information to this thread. Im going to be putting an ABA/1.8 counterflow head in my fox very soon.....tt big valves, 266 cam for now. anyway im going to have to convert to A2 digifant 2, mainly on fact that i can get a higher rev limit with a chip, and a knock sensor. fox digifant sucks cause you have a 6,000 rpm cutoff thats not changable and no knock sensor. but looking into this thread has made me feel better and laugh at others for mocking me for wanting to keep it simple and stay with digi2 cause there are so many ways that people like you guys have figured out how to make it a way better system than stock. Big BUMP for this very informative thread http://****************.com/smile/emthup.gif


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

I just wanted to throw out some more ideas & stimulate some more discussion.
I'm still dialing in my setup with the BMW AFM but I couldn't help but think about the map sensor idea.
The pot ranges from 5-600 ohms @ rest
900
1000
1100
1200
1100
1000
900
back to 600 wide open
but for the most part it's around 1000 ohms give or take.
you can easily idle it @ 1000 ohms & the ecu should compensate throughout the rpm range. The fueling can be fattened up with bigger injectors & an adjustable FPR.
Maybe use a wot switch triggered 600 ohm reisistor to tell the ecu the AFM (it thinks) is wide open so it'll only rely on the temp sensor.
In summary:
Use a 1k ohm resistor to replace the entire POT & just use a triggered 600 ohm resistor to tell the ecu the POT is maxed out(wide open).
The Temp Sensor will still be used, it'll just be relocated to somewhere in the intake tract or just hanging somewhere cool outside the intake.
Maybe we could use a TPS inplace of the 1k ohm resistor & 600 ohm for more progressive input. TPS tuned for 600-1200-600ohms.
I realise some of this has been covered already.
Some have already tried using just a 1bar GM map sensor with some success. I don't have his name right now but iirc he had rich running issues, injectors being too big (G60's) on a near stock 1.8L.
Staying with the map idea you could use a piggyback fuel controller to callibrate the Map sensor.
I was looking at this Apexi SAFC2








Info here:http://www.apexi-usa.com/electronics_safc.asp
The Greddy Emanage








http://www.greddy.com/prod_e_manage.htm

Or these two from Split Sec
















http://www.splitsec.com/products/calibrators.htm
I'm aware of the their whole MAF Kit.
This is the ultimate one short of going full standalone. 
The HKS Vein Pressure converter, specifcally designed to replace the stock barndoor AFMS. Built in Map Sensor & Temp Sensor
Unfortunately these have been discontinued








but they can still be found on Ebay, etc








http://www.hksusa.com/products/more.asp?id=858
I even found a low buck homemade map voltage adjuster alternative from the Jeep guys.
http://www.angelfire.com/my/fan/MAP_adjuster.html



_Modified by Digiracer at 1:55 PM 8-16-2004_


----------



## squareboy (Oct 11, 2003)

Legendery post, good work by all.
My project at the moment is to weld another throttle body mount to the other end of a stock 8v plenum chamber with a complete setup from TB,AFM to air box. Link the two throttle body arms up with a rose type joint and in theory get half the air resistance. The second AFM would not need to be wired up it would simply be there two equal out resistance on both sides to allow the wired AFM to swing on a standard type curve as airflow increases. It makes sense to me that AFM's should only swing fully open when the engine is flowing at it's maximum potential. Anyone that loosens the spring rate in an attemt to decreased air resistance is mistaken as the engine will run too lean at low loads and not add fuel proportionally as air flow increases.
I havn't heard of anyone testing this sort of setup although I'm sure many have as it seems so obvious?


----------



## Digiracer (May 5, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

How about this idea. (Flame Suit On)








Move the Temperature Sensor somewhere in the intake tract(anywhere cool).
Move the stock AFM/housing/POT to the exhaust side, somewhere farther down towards the resonator.
Use the POT/AFM housing as a blow through design & recalibrate the spring tension to compensate for less pressure. (almost using it as a crude Map Sensor/exhuast pressure sensor in this case)
If you guys think about it, technically it would work as rediculous as it may sound to some of you. The only issue is would the unit itself surviving the temperatures the exhaust can emit/transfer. 
You could get trick about it & coat the AFM door & housing with a thermal coating. It wouldn't be much a restriction if any on the exhaust side infact it probably would flow alittle better through this short section using say a TT 2.25 " exhaust.
Think about it, The air density/volume is metered coming into the engine. Why not meter it coming out of the engine? 
The housing & door would not have any trouble withstanding the heat, it's the POT & plastic gear wheel I question.


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## OhioBenz (Dec 6, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

hahahahahaha


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## 2002maniac (May 3, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

Hmm, the only problem would be that the Density/volume of exhaust gas is much greater than intake air. It would work if you could properly calibrate the afm but hat would be close to impossible. I think the best of both worlds would be a map sensor setup.


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## squareboy (Oct 11, 2003)

Is my idea crap?? As with any idea the proof is in the doing and no amount of theory will make it work, these sort of topics always spark off mad thoughts. 

Digiracer that adjustable FRR sounds that ticket, where did you order it from and will the install involve changing the fuel lines?


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## xr4tic (Dec 10, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

I don't think this would work at all. In fact I'm fairly certain it will not, and will probably take way too much time to try to explain.
In summary: you need to calculate fuel injection based on air mass (temp and flow), but exhaust flow would change based on the A/F ratio and air mass.
So not only would you have to measure exhaust flow, you'd have to measure exhaust temp AND A/F ratio, plus with temp losses due to heat radiation through coolant and the air, you'd have to take into account engine bay airflow and coolant temps and attempt to guess about these losses.

_Quote, originally posted by *Digiracer* »_ How about this idea. (Flame Suit On)








Move the Temperature Sensor somewhere in the intake tract(anywhere cool).
Move the stock AFM/housing/POT to the exhaust side, somewhere farther down towards the resonator.


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## xr4tic (Dec 10, 2001)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Digiracer)*

If you wanted to go with an piggy-back AFM of some sort, then the Split Second PSC1 would probably work perfectly.
It could take the MAP sensor voltage, and output a voltage based on RPM and MAP
The interesting part is, you could theoretically tune it using the PSC1, then take the PSC1 adjustments and apply them to the chip, and remove the PSC1, essentially using it only for tuning.
I've got one laying around I've been meaning to hook up, just haven't had the time to do it. Maybe I'll have some time labor day weekend to play with it


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## foobar (Jul 1, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (Coupe__88)*

Back from the dead.








I got an AFM with the bosch part number 0280203001 which belongs to a BMW 3.0si / 530i and plan to put it on my digifant II. The problem is the wiring harness has seven pins on it rather than four. Four of the pins are numbered just like the four pin conector on the digifant unit, has anyone tried to use this type by just connecting the four available? (great thread, thanks in advance.







)


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## foobar (Jul 1, 2004)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (foobar)*

TTT
hmm... dead for good?


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## KOOTER (Aug 13, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (foobar)*

Here is something you guys need to know about.This will work just as easily for you as anybody else.You will need to get a TB from a automatic passat or corrado that has a TPS on it(or fashon your own).You will also need some sort of MAP or MAF to calibrate.
This unit will also advance and retard as much timing as you could ever want.
You will also need a IAT sensor.
http://www.idaautomotive.com/c...n.htm

_Modified by KOOTER at 2:52 AM 12-7-2004_


_Modified by KOOTER at 2:53 AM 12-7-2004_


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## KOOTER (Aug 13, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (KOOTER)*

Software screen shot.


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## mxman (Jul 31, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (KOOTER)*

my brit friend who helps with some cars in a shop, he was saying we should be taking a voltmeter and measuring the voltage across the VAM to see if its hitting 4.75 volts if not at WOT it might run lean and blow it all up


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## autobahnjs (Sep 14, 2002)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (mxman)*

just did the swap..turned the co down a bit and turned the inside clock back 8 click but i find that may be to much..the door of the vane will not sit close..it says a bit open sold i adjust it to 6 click so it makes the spring tighter? will i lose on power? i am running 3.6 fpr may go to 4.0...


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## mxman (Jul 31, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (autobahnjs)*

I seem to own the newer style Bmw 535 Airmeter, 0 280 203 016
interesting, i assume this isnt going to work, i had it wired up, i fired up the car with the spring at a bunch of different tensions with no success...suggestions ? I think I will map it with the ohm meter


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## mxman (Jul 31, 2003)

*Re: Digi 2: Lets get some serious MAF conversion discussion goin on (autobahnjs)*

I seem to own the newer style Bmw 535 Airmeter, 0 280 203 016
interesting, i assume this isnt going to work, i had it wired up, i fired up the car with the spring at a bunch of different tensions with no success...suggestions ? I think I will map it with the ohm meter


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## Hard_Rocker (Nov 1, 2002)

so; it seems after reading this entire thread, and seeing the GM MAP sensor information, that this needs to be done; using a multimeter to measure the output from the stock VAM while driving, while at the same time having a MAP sensor rigged in and measuring the signal from it, to see how much they deviate... presumably if after this simple test they are similar enough, either in actual value or in curve shape, the circuitry to adapt the signal would be easy to rig up, perhaps as simple as a pot to reduce output voltage... now I just need to get my hands on two multimeters... http://****************.com/smile/emthup.gif


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## mike86xj (Sep 26, 2003)

*Re: (Hard_Rocker)*

so is there any new info on any of the map or maf sensors?
i'm really interested but dont want to be a guinea pig right now (finally finished my aba swap) gotta take er easy for a while


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## Black_cabbie (Jul 16, 2003)

*Re: (mike86xj)*

You can forget the MAF, MAP sensors. 
AFM is the only one that will work with the digi. If you already got the ABA and cam and exhaust and chip etc etc etc, then you will benefit from the bigger 3.5L AFM. Otherwise its too lmuch hassle for no gains.


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## team~bunny (May 16, 2002)

*Re: (Black_cabbie)*

http://****************.com/smile/emthup.gif


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## team~bunny (May 16, 2002)

*Re: (team~bunny)*

Ok so i read this hole post last night and it got me thinking so I started to brain strorm the idea of mounting the guts of the afm to the trottle bodie this is just for an experiment as of now if it if it works then ill be fabercating something more pleasing to the eyes. 








ok this is whats up so far, the throttle shaft does not turn the same way the afm does so at ideal it would tell the ecu the afm was wide open.








So question for you guys.. can I swicth the wires around the come off the board? 
And what is the other two brown wires going too is that important?
thanks ted


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## ferchooo (Oct 18, 2004)

no


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## slammedGTIballer (Jun 23, 2004)

*Re: (ferchooo)*

this is a great post.. just read the whole thing at work







now i have some questions.. i just bought a BMW 535 AFM, g60 fuel rail, g60 green top injectors, p-flo intake, and porsche 944 FPR... has anyone done this before? i assume yes since its pretty close to what ive read on here.. my head just hurts from reading so much.. what do you all expect HP/TQ gains to be with my engine swap (see my signature at the bottom of my post)... especially want some feedback from Digiracer and DanielAdams since they seem to be the experts! great job guys!!! http://****************.com/smile/emthup.gif


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## WolfzGangVR6 (Jan 1, 2002)

*Re: (slammedGTIballer)*

posting for some good info...


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## notldubber (May 3, 2008)

Is there a summary post anywhere in this?


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## ChrisAudi80 (Apr 18, 2011)

I know this is an old thread, but I thought maybe one of these kits could be useful:
http://www.splitsec.com/products/mafkits/MAFkits2.htm

I read the early posts and noted the comments about CFM values would be out of range for the digi-II. I would have to ask SplitSec if it would work on a 2L. A 3" MAF on a NA 2L seems a bit big.

I have an ABK automatic running on digi-II, so cannot go SEM.
If I could find a way to spice it up a bit with the MAF conversion kit (along with a cam and exhaust), that would be cheaper than going 1.8T.

The ABK is very similar to the ABA. Taller deck, for one.


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## bambam08 (Feb 10, 2009)

@team bunny any more input on your test?


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## simon_C (Oct 5, 2006)

I hate to exhume old threads, but I have been contemplating this idea lately as well and was sad to see that the thread died last year. 
I live in california so i can't switch my engine management to something better, so I was looking for something to replace the ****ty AFM with.


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## ChrisAudi80 (Apr 18, 2011)

simon_C said:


> I hate to exhume old threads, but I have been contemplating this idea lately as well and was sad to see that the thread died last year.
> I live in california so i can't switch my engine management to something better, so I was looking for something to replace the ****ty AFM with.


I am glad you did exhume this.

I did find a way to get rid of the AFM. I put a piggyback ECU in my B4 Audi 80 with a 2.0E Digi-II with autotrans. This piggyback can be run in AFM elimination mode.
It was quite easy to wire in. However, I am switching to AEB Quattro manual now, so don't need the piggyback anymore.
Its called MAP-ECU3. You run the ECU Map based. Fairly easy to tune. An AFM voltage signal goes to the stock ECU.

Wanna buy my piggyback?


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## simon_C (Oct 5, 2006)

ChrisAudi80 said:


> I am glad you did exhume this.
> 
> I did find a way to get rid of the AFM. I put a piggyback ECU in my B4 Audi 80 with a 2.0E Digi-II with autotrans. This piggyback can be run in AFM elimination mode.
> It was quite easy to wire in. However, I am switching to AEB Quattro manual now, so don't need the piggyback anymore.
> ...


Sure, PM me details/price


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## duhafnusa4 (Dec 20, 2007)

TTT


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