# Any standalone systems that use a MAF?



## nick526 (Sep 29, 2006)

Hey all, I'm getting close to finishing up my engine and I'm starting to think about engine managment.
There's plenty of good systems out there for my application (NA) but I'm curious if anyone knows of a system that uses (or can use) a mass air flow sensor for the primary load sensing rather than a MAP. My reasoning is that with such a system, adding ITBs in the future would only really require a custom air box (and some small tuning changes perhaps) and not a complete re-map.
Any sugestions or opinions are welcomed


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## B4S (Apr 16, 2003)

*FV-QR*

Megasquirt can be configured to run a MAF http://****************.com/smile/emthup.gif


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## need_a_VR6 (May 19, 1999)

*Re: FV-QR (B4S)*

Yep, I had it on mine but never got around to doing a MAF tune. Just used it for logging. 
You'll still want to do some tuning with changes even with a MAF, it just makes the adjustments smaller.


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## Issam Abed (Feb 12, 2004)

*Re: Any standalone systems that use a MAF? (nick526)*


_Quote, originally posted by *nick526* »_My reasoning is that with such a system, adding ITBs in the future would only really require a custom air box (and some small tuning changes perhaps) and not a complete re-map.

Even if you add ITB's,the difference in the tune is going to be less than anything to worry about.
MAP based system > MAF based system.
Go MAP http://****************.com/smile/emthup.gif


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## need_a_VR6 (May 19, 1999)

*Re: Any standalone systems that use a MAF? (Issam Abed)*


_Quote, originally posted by *Issam Abed* »_
Go MAP http://****************.com/smile/emthup.gif 

I'd even go as far as ditching that for tps (alpha-n) based load on an ITB car.


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## Issam Abed (Feb 12, 2004)

*Re: Any standalone systems that use a MAF? (need_a_VR6)*


_Quote, originally posted by *need_a_VR6* »_
I'd even go as far as ditching that for tps (alpha-n) based load on an ITB car.

Well I just assume everyone ends up in the FI department (cough *like you will be soon" cough)


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## nick526 (Sep 29, 2006)

*Re: Any standalone systems that use a MAF? (Issam Abed)*

Thanks for the advice everyone. 
It seems like a MAP setup would be pretty painfull with ITBs though, since there's no plenum to get a reliable signal from. Throw some big cams in the mix and the situation is even more difficult, no?
Issam, why is a MAP system better than a MAF system in your opinion? From my own experience I have seen a much higher failure rate on MAF sensors than MAP sensors (granted, mainly on stock customer vehicles, not custom tuned stuff) so I can see that as a drawback, but almost every manufacturer is using MAFs these days, there must be some advantage?
Do M3s and those old ITB Toyota engines use a MAP and/or Alpha-n system for their ECUs? 
I'm thrilled that this post is getting some responses, thanks again guys


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## Issam Abed (Feb 12, 2004)

*Re: Any standalone systems that use a MAF? (nick526)*


_Quote, originally posted by *nick526* »_
It seems like a MAP setup would be pretty painfull with ITBs though, since there's no plenum to get a reliable signal from.

On ITB's the MAP signal is taken from the manifold.So if you have 4 runners then you tap each runner for a 1/2" NPT to barb fitting,run the 4 lines into a vaccuum block and run the ecu off one of the vaccuum lines coming from the block.
Whether you have a plenum box or not does not affect the vaccuum signal.

_Quote, originally posted by *nick526* »_
Issam, why is a MAP system better than a MAF system in your opinion? From my own experience I have seen a much higher failure rate on MAF sensors than MAP sensors (granted, mainly on stock customer vehicles, not custom tuned stuff) so I can see that as a drawback, but almost every manufacturer is using MAFs these days, there must be some advantage?

if you are talking about VAG, they are the only current manufacturer that I know that still uses a MAF in there system but they also use it in conjuction with a MAP sensor.
On the ME-7 systems you have the option of eliminating the MAF set up in the software so that is a mute point.
Most manufacturers these days are moving away from MAF based systems due to the high failure rate and cost of production.Much easier ways of getting inputs into the system.

_Quote, originally posted by *nick526* »_
Do M3s and those old ITB Toyota engines use a MAP and/or Alpha-n system for their ECUs?

The 4A-GE Silvertop motors used a MAF based system which was a total PITA due to high failure rate.The later models switched over to a MAP based system and Toyota has not used a MAF based system since.


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## need_a_VR6 (May 19, 1999)

*Re: Any standalone systems that use a MAF? (Issam Abed)*


_Quote, originally posted by *Issam Abed* »_
On ITB's the MAP signal is taken from the manifold.So if you have 4 runners then you tap each runner for a 1/2" NPT to barb fitting,run the 4 lines into a vaccuum block and run the ecu off one of the vaccuum lines coming from the block.
Whether you have a plenum box or not does not affect the vaccuum signal.


Even if you have a good 'averaged' vac signal, it's still not enough. You're right it's not the plenum effect, it's just area of the throttle vs displacement of the engine. You get multiple throttles and a very small throttle angle change is a large change in MAP at lower rpms. This makes tuning via a map sensor very hard. Believe me I've done it a bunch, sometimes sucessfully, sometimes not! It really depends on the setup, but I've never had a car run better on a MAP then AlphaN with a car with ITBs.


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## nick526 (Sep 29, 2006)

*Re: Any standalone systems that use a MAF? (Issam Abed)*


_Quote, originally posted by *Issam Abed* »_
if you are talking about VAG, they are the only current manufacturer that I know that still uses a MAF in there system


As far as I know Ford, GM, Chrysler, Mazda (not sure about their rotary), Nissan, Porsche, Hyundai, and Kia all still use MAFs on naturally aspirated engines, Ford even uses a MAF (and a MAP) on their turbo diesel engines.

_Quote, originally posted by *need_a_VR6* »_
You get multiple throttles and a very small throttle angle change is a large change in MAP at lower rpms. This makes tuning via a map sensor very hard.

That's what I was thinking. Wouldn't a MAF work well here since the dynamics of the individual throttles wouldn't fool a sensor that is directly measuring actual airflow into the engine rather than a system that tries to extrapolate this information via vacuum signal or throttle position? 
It seems to me like one would need to tune with alpha-n for small throttle angles and then switch to MAP for high load conditions to get good driveability out of an individual runner setup. Couldn't a MAF cover all the bases?


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## need_a_VR6 (May 19, 1999)

*Re: Any standalone systems that use a MAF? (nick526)*

Yes MAF could work well, but you run into all the packaging problems associated with making a plenum and an intake tube with throttles. If you're willing to jump that hurdle, it could work very well. 
If you're looking for the best compromise of alpha and map, you want to blend by rpm mostly. You will have transition where the throttles are actually sized for the motor again at higher revs and you will be able to start using map based load. 
Here's a good article on map vs alpha and some load blending stuff http://77e21.info/mstuning.htm I tried using blended tables before (hybrid-alpha, not the ms2 setup in the article) with not so great results. Hybrid alpha (in MS1) blends on the load axis instead of the rpm axis, which isn't what you want for a lairy n/a car.


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## Issam Abed (Feb 12, 2004)

*Re: Any standalone systems that use a MAF? (nick526)*


_Quote, originally posted by *need_a_VR6* »_This makes tuning via a map sensor very hard. Believe me I've done it a bunch, sometimes sucessfully, sometimes not! It really depends on the setup, but I've never had a car run better on a MAP then AlphaN with a car with ITBs.

You are not the only one Paul....
This is how I got my first introduction into SEM's was trying to get SDS to work on my 4A-GE motor with 45's.After that I gave up and went with Carbs...
But yes I do agree that it also depends on the set up being used.On ITB sets up I find that a vaccuum manifold with equal length vaccuum hoses between 

_Quote, originally posted by *nick526* »_
As far as I know Ford, GM, Chrysler, Mazda (not sure about their rotary), Nissan, Porsche, Hyundai, and Kia all still use MAFs on naturally aspirated engines, Ford even uses a MAF (and a MAP) on their turbo diesel engines.

Interesting.
As far as I know the Mazda/Ford/Nissan/Kia and Toyota all outside of North America run MAP based systems.
Only ones I know that run a MAF out of Japan are Mitsubishi & Hyundai (well the Genesis Coupe)
As for the Diesels...same again.None of them run a MAF and that is:
Nissan Frontier 3.0 TD
Toyota Hilux 3.0 TD
Mazda B2500 2.5 TD
Mitsubishi Sportero 2.8 TD
etc....


_Quote, originally posted by *nick526* »_
Couldn't a MAF cover all the bases?

Yes it can but why over complicate an inlet system with a part that is prone to failure? I am sure you trying to get around the vaccuum source of a MAP based system but that should be the least of your worries compared to air box + parts + more parts.
Whatever the case I would love to see what you come up with.


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## nick526 (Sep 29, 2006)

*Re: Any standalone systems that use a MAF? (Issam Abed)*

Well, I wouldn't know anything about what OEMs are doing over seas, I only know cars that rolled into my bay when I worked for an independent shop.
Something like this seems easy enough to put together:
http://bildon.com/catalog/Deta...av=66




_Modified by nick526 at 3:20 AM 7-29-2009_


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## need_a_VR6 (May 19, 1999)

*Re: Any standalone systems that use a MAF? (Issam Abed)*


_Quote, originally posted by *Issam Abed* »_On ITB sets up I find that a vaccuum manifold with equal length vaccuum hoses between 


I'm sure there was more to that sentence.. but, I've never had any luck with vac manifolds, or reservoirs helping the map range issue. It sure does help for brake assist though.
I agree that MAF might be more trouble then its worth. I had it on my last setup, but I'm not going to bother adapting it for my next one.


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## nick526 (Sep 29, 2006)

*Re: Any standalone systems that use a MAF? (need_a_VR6)*


_Quote, originally posted by *need_a_VR6* »_
I agree that MAF might be more trouble then its worth. I had it on my last setup

What was so troublesome about it? The airbox or the tuning?


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## need_a_VR6 (May 19, 1999)

*Re: Any standalone systems that use a MAF? (nick526)*

Mine was easy, it was already there. My new intake setup I need 3.5" and no one offers one that size so I'd have to make a housing. More trouble then it's worth at least for me at this point. 
Making an airbox that doesn't leak AT ALL or restrict airflow to the ITBs. You're also going to have to match the MAF to your physical hardware which will probably make it a little 'big' for the hp level you'll see and lose some resolution there. If you're set on it, for sure do it, but just be aware of how much extra effort it'll take to use it vs how little time it takes to retune a car after small mods. Large difference you'll want to retune anyway.


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## nick526 (Sep 29, 2006)

*Re: Any standalone systems that use a MAF? (need_a_VR6)*

I'm not really set on anything as far as managment goes, I'm not even set on running ITBs for that matter.








Cylinder head and intermediate shaft are still in the shop, still waiting for pistons and rods in the mail (one moth and counting haha,) almost done honeing the stock ABF manifold, haven't done any calculations for fuel requirements/injector size yet, etc...
Managment is still in the brainstorming stage, hence the thread.
Question for you guys, are there any difficulties with MAP readings in a conventional intake when large duration cams with a lot of overlap are used? The point about signal resolution with an oversized MAF made me wonder if the same problem may be encountered with such cams.


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## need_a_VR6 (May 19, 1999)

*Re: Any standalone systems that use a MAF? (nick526)*

The bigger things get (compression and cam size) the 'jumpier' the MAP signal will get. On a plenum car it's not THAT bad and clears up with increasing rpm. I'd have to look at some logs but my normal MAP jitter is about 4-5kpa at worst with 10:1 compression and 268s.


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## Jefnes3 (Aug 17, 2001)

*Re: Any standalone systems that use a MAF? (need_a_VR6)*


_Quote, originally posted by *need_a_VR6* »_The bigger things get (compression and cam size) the 'jumpier' the MAP signal will get. On a plenum car it's not THAT bad and clears up with increasing rpm. I'd have to look at some logs but my normal MAP jitter is about 4-5kpa at worst with 10:1 compression and 268s.

Put a small snubber between the source and sensor.
(similar when you have a noisy boost gauge)
Try pulsations on a 2 Rotor 13B Mazda at low revs.
Use dTPS/ dTime for accel pump functions, as opposed to MAP change rate.
-Jeffrey Atwood


_Modified by Jefnes3 at 10:20 PM 7-31-2009_


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## nick526 (Sep 29, 2006)

*Re: Any standalone systems that use a MAF? (Jefnes3)*

What's a snubber? Like a restrictor in the vacuum line? Forgive my ignorance, but what software do those accel pump functions come from?


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## need_a_VR6 (May 19, 1999)

*Re: Any standalone systems that use a MAF? (Jefnes3)*

I use a MIG tip in the vac line for the MAP, and use tps based accel for those reasons.


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