# VR Sensor at what tooth on 60-2 in ABA at TDC?



## patatron (Aug 10, 2003)

I am working on an ABA crank triggered megasquirt set-up using wasted spark without EDIS. Due to not being able to find a car to stuff my ABA into, I have chosen to temporarily set this up on my other megasquirted car that is currently running a distributor. I plan on leaving this car as a distributor car, so this will be a temp install to test out this set-up. I am going to fabricate a 60-2 wheel on the crank to simulate an ABA crank trigger. I am basically trying to find out what tooth on the wheel the VR sensor points at when the motor is at top dead center. I am attatching this diagram for tooth numbering in case you are not sure. Any help would be appreciated!








And my test car...








And the motor I dont have a car for yet, causing my issues...


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## lugnuts (Jul 26, 2001)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

Im sent


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## Audi4u (Jun 29, 2002)

13-14 should get you within range.


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## sdezego (Apr 23, 2004)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

The missing tooth is at 90* BTDC on #1 cyl. 
This may help: http://forums.vwvortex.com/zerothread?id=2736172
I am contemplating doing the same thing on my 8v corrado for the very short term. ...just to get everything set for my 20v so I can drop in the new motor, switch maps and be ready to go w/o having to tweak ign settings and crap for wasted spark 60-2.
Just havent nailed everything down yet.
Shawn


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

I re-did the image as I think it would sit given your guys suggestions, how does this look?


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## sdezego (Apr 23, 2004)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

You may want to change your image slightly.
1.) You are counting teeth CW, when you should technically be counting then CCW after the notch. Remember, since the missing teeth are ~90* BTDC. The ECU sees the missing teeth, resets, starts counting then triggers on say the 14th tooth. 
2.) Your numbering scheme may or may not be off depending (since it is all relative). I know that TDC is on the 14th tooth. This is actually the 15th tooth if you count from the first mising tooth like you are doing. So, TDC is the 14th actual raised tooth.
Here are a few pics to orient the situation. You can see that the -2 is 90* BTDC due to the relation of the Vr sensor. ...and 180* from the #1 and #4 Pistons in relation to the crank.









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Next 3 Pics show the crank Pos and missing teeth pos at 90* BTDC. From what I saw, the VR would actually be pointing between where 1 & 2 would be.
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Pic is a little deceiving becuase of the angle. The notch should actually be pretty much in line with the rod journal for #2 and #3.
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Feel free to make any corrections to my terminology. I am certainly no expert on the matter...
Shawn


_Modified by sdezego at 2:52 PM 10-24-2006_


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (sdezego)*

Thank you for the pictures! That made things much more clear! I also got confirmation from "Lugnuts" that my new image was accurate...(Paying no attention to my numbering)










_Modified by patatron at 10:59 PM 10-24-2006_


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

I recently purchased this 60-2 trigger wheel from 034 motorsport. I am a bit confused as I have never seen the 2 tooth gap look like this on a trigger wheel before. There is barely even a valley where the gap is supposed to be. Is this OK, or Is this a problem? I also have the stock wheel off of an ABA crankshaft, and am probably gonna mount that to the crank instead because of this. Any thoughts on this?


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## tyrone27 (Sep 7, 2001)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

thats how mine is on the tec2


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## lugnuts (Jul 26, 2001)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (tyrone27)*

Electromotive originally has a deeper gap, then changed it to the current style. the first tooth after the gap is hard to read so they said. 


_Modified by lugnuts at 11:49 PM 10-26-2006_


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (lugnuts)*

For my initial run, I think I am going to mock up this ABA trigger wheel on a dual 8V pully, and run the v-belt on just the inner groove. I am just gonna tack weld the ring to the pulley, make sure it is strait, and then plug weld the front holes on the Trigger wheel. This will allow me to do the testing I am planning, and I think it will work well.


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## sdezego (Apr 23, 2004)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

Just Curious, why are you going to run what looks like the Ford EDIS VR pickup as opposed to mounting the ABA? Sounds like you want to mock the ABA completely which is why I ask.
Shawn


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (sdezego)*

I figured they are both VR sensors, and should act the same, and the ford EDIS sensor is much cheaper. Good point though!


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## sdezego (Apr 23, 2004)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

I only ask, becuase we know VW and their sensors. i.e. the Hall








I would think that in this case either should work, but I have not made it far enough in my engine build to warrant figuring out if there is anything tricky with the ABA VR. Like extra tinkering with the pots (reverse intergalactic polarity or some nonsense like that).
S


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## TheArchitect (May 4, 2006)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (lugnuts)*

Lugnuts, 
No, none of the 034 guys are ex Electromotive engineers.
Electromotive changed thier design because it was wrong.
The issue is that as you transition from toothed section to non toothed section, the magnetic return path becomes less and less.
So what you want to see is a toothless area that doesnt have edges, while having an opening and closing area with less tooth gap.
This charectoristic is what makes a nice smooth voltage transition from toothed to toothless, without a huge spike on the VR output when it finally sees the first tooth after the missing section.
The older (deep valley missing tooth section) is only suitible for hall effect sesnors.


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## lugnuts (Jul 26, 2001)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (TheArchitect)*

I'll gladly remove false information, but I know Lance at Profuel worked with Alex Long of (Electromotive), and he refers to the ECU 882-X as "My ECU".
Not only that, but the 034 fuel setup parameters are exactly like the old TOG/IOT , or UAP/POT if you prefer.
In addition, the 034 has internal high current ignition drivers, which is pretty rare.
So you can see where i would make the connection. 

Thanks for the info on the missing tooth setup.
kevin


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## TheArchitect (May 4, 2006)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (lugnuts)*


_Quote, originally posted by *lugnuts* »_I'll gladly remove false information, but I know Lance at Profuel worked with Alex Long of (Electromotive), and he refers to the ECU 882-X as "My ECU".
Not only that, but the 034 fuel setup parameters are exactly like the old TOG/IOT , or UAP/POT if you prefer.
In addition, the 034 has internal high current ignition drivers, which is pretty rare.
So you can see where i would make the connection. 

Thanks for the info on the missing tooth setup.
kevin

I can understand the confusion.
Yes, Lance sold electromotive products, however his affiliation with electromotive, as well as his statements regarding it being "his" ECU are slight exagerations.
You are now communicating with the actual designer, who has no affiliation, past present or future, to Electromotive, or the late Alex Long.
The notion of scaler and offset to the fuel calculation is as a result of stuff I learned way back in school, and it only makes sense to apply that basic concept to the load variable in a speed density system.
One of several concepts I think Electromotive got right.
Kinda surprised other systems dont use it too, it has the advantage of increasing the resolution of the VE cells when the engine VE is poor, which is why this type of systems mapping has a defualt map of all 1.00, which means the fuel uses the scaler and offset ONLY for fuel calcs.


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## lugnuts (Jul 26, 2001)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (TheArchitect)*

Interesting, one thing that drives me nuts is exaggeration.
Compared to the other domestic systems like Holley and DFI, I do like the span and offset method.
The Autronic has a base fuel cal, that is = to the Inj PW at 100 kpa and 100 in the ve table. The Inj PW is then multiplied by the manifold pressure. So you can run all 100 in the ve table as well, until you get into the meat of the cam where hopefully it will flow some major air.


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## TheArchitect (May 4, 2006)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (lugnuts)*


_Quote, originally posted by *lugnuts* »_
The Autronic has a base fuel cal, that is = to the Inj PW at 100 kpa and 100 in the ve table. The Inj PW is then multiplied by the manifold pressure. So you can run all 100 in the ve table as well, until you get into the meat of the cam where hopefully it will flow some major air.

Yes, this sounds like a good way to do it too.
This way I suppose you could swap out the MAP sensor, and as long as the ECU knows what 1 bar is, then the basic fuel curve would apply.


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (TheArchitect)*

Any thoughts on my above Trigger wheel method?


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## TheArchitect (May 4, 2006)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*


_Quote, originally posted by *patatron* »_Any thoughts on my above Trigger wheel method?


What exactly is your question?


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (TheArchitect)*


_Quote, originally posted by *TheArchitect* »_

What exactly is your question?

Just wondering if someone has done something like this before with the ABA wheel. Seems like a good inexpensive option.


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

Well she's all welded up, and set-up so that the crank sensor will be mounted near the rear of the engine block...








I will post updates as to how well it works as my testing goes on. Thanks for all of your help guys!


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## TheArchitect (May 4, 2006)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*


_Quote, originally posted by *patatron* »_Just wondering if someone has done something like this before with the ABA wheel. Seems like a good inexpensive option.

Well I would comment that the VR sensor you use does need to be compatible with the tooth size you will be using.
If you plan to use the ford VR sensor, then you will want to be sure it ran a smaller diameter wheel than the 60-2 you are adding on.
The bias magnet in the VR sensor will be sized based on a tooth width range that may not work if you go to a tooth that is considerably smaller.
Also your method of centralizing the wheel to the pully is very critical to prevent runout. With a gap of .040 and runout of .020 (I seen far worse), some amplifiers may not properly trigger on the variation in sensor amplitude.
The ubiquitous LM1815 is one such amplifier that does not care for target runout.


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (TheArchitect)*


_Quote, originally posted by *TheArchitect* »_
Well I would comment that the VR sensor you use does need to be compatible with the tooth size you will be using.
If you plan to use the ford VR sensor, then you will want to be sure it ran a smaller diameter wheel than the 60-2 you are adding on.
The bias magnet in the VR sensor will be sized based on a tooth width range that may not work if you go to a tooth that is considerably smaller.
Also your method of centralizing the wheel to the pully is very critical to prevent runout. With a gap of .040 and runout of .020 (I seen far worse), some amplifiers may not properly trigger on the variation in sensor amplitude.
The ubiquitous LM1815 is one such amplifier that does not care for target runout.


I mic'd the runout to the outer perimeter of the pulley, and it is virtually perfect. I will update with my luck on the Ford sensor.


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

Well I mounted the wheel to the car, and turned the engine over with a small piece of steel bolted to the PS bracket holes on the back of the block. I bent it so it was almost toutching the wheel. And then I checked the runout with a feeler gauge checking the most extreme runout spot vs. the spot 180 degrees from it, and have almost exactly .5mm of runout. I then fired up the car and looked at it with the tire/wheel out of the way and it looks virtually perfect while it is running...


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## Fox-N-It (Jul 23, 2003)

I know the EDIS sensor, in the stock setup, should be within 1mm of the wheel. 
I'm intrested in seeing what results you get out of this. Better 60-2 support for MS would open alot of doors.


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## patatron (Aug 10, 2003)

*Re: VR Sensor at what tooth on 60-2 in ABA at TDC? (patatron)*

Some updates. I made the bracket for the sensor, and have it all set-up. Looks to work pretty good. The gap seems to be right between 1mm, and .5mm depending on where the crank position is, I hope that is a reasonable tolerance.


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