Challenge: add Audi "trigger wheel" to code

Testing and development of Megasquirt 3

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VolvoGuy50
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Re: Challenge: add Audi "trigger wheel" to code

Post by VolvoGuy50 »

elaw wrote:Well if there's anything Audi is known for (or at least was back then) it's making things complicated.

The original system was a joint development between Audi and Hitachi, who supplied the ECU and some other parts (including the VR sensors, and even the fuel injectors on the 7A motor). I've always wondered how much of the design of that system was Audi's and how much was Hitachi.

The other thing I've always wondered is how much arm-twisting Audi had to do with Bosch to get them to adapt their already-established Motronic system to Audi's goofy trigger setup!
:lol: I have a feeling Hitachi's only part was making the stinkin' hardware, nothing more. It's the same deal with Volvo. Everything is 10000x overcomplicated from the way it should be. i.e. each of my headlight BULBS has a dedicated fuse...which is connected to a low-beam fuse, which is then connected to a front light fuse, which then goes through a fuse box fuse, and FIANLY to the B+ line.... What was wrong with a single lowbeams fuse that they felt the need arose to QUADRUPLE fuse it? :evil:
1992 Volvo 740 Wagon - Beater Car...CAI, 16T, catback, MS3/MS3X, & HID's
1996 Eagle Talon TSi AWD - Daily Driver...RAI, Big 16g, 3" TBE, HID's, etc.
elaw
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Re: Challenge: add Audi "trigger wheel" to code

Post by elaw »

James,

Hey for what it's worth, I've decided to go a different route on my car - hopefully in the next couple of weeks I'm going to switch to the same type of 60-2 sensor Savagerocco's using.

So the ring-gear-triggering code won't be of any use to me, but hopefully it'll be useful to others!
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

Be alert! America needs more lerts.
VolvoGuy50
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Re: Challenge: add Audi "trigger wheel" to code

Post by VolvoGuy50 »

elaw wrote:...I'm going to switch to the same type of 60-2 sensor Savagerocco's using.
Good choice IMO. In my view, it's best to go with the most standard installation possible, since the more "unique" things you add, the more and more complicated stuff gets.
1992 Volvo 740 Wagon - Beater Car...CAI, 16T, catback, MS3/MS3X, & HID's
1996 Eagle Talon TSi AWD - Daily Driver...RAI, Big 16g, 3" TBE, HID's, etc.
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Re: Challenge: add Audi "trigger wheel" to code

Post by jsmcortina »

Ah, without an active tester I won't be adding any code.

James
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elaw
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Re: Challenge: add Audi "trigger wheel" to code

Post by elaw »

Sorry about that...

I originally hoped I'd be able to set it up so I could use either trigger method, but I don't think it's mechanically possible. One of the OEM trigger signals comes from a pin on the back of the flywheel ("back" = the side facing the engine). The new hall pickup mounts in place of the rear main seal, and I think that pin needs to be removed so it doesn't chew through the wire going to the new sensor.
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

Be alert! America needs more lerts.
elaw
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Re: Challenge: add Audi "trigger wheel" to code

Post by elaw »

Okay, so it's time for me to flip-flop again! :lol:

I made a last-ditch effort recently to combat the sync-loss problems I've been having ever since I switched to crank triggering on this car, and I think I finally may have fixed it! :yeah!: To make a long story short, let's just say when you have electrical-interference problems, it isn't always the grounds that are the problem, sometimes it's on the +12 side.

I want to give it a couple more weeks of driving to make really really sure but I haven't gotten a random sync loss in over a month now. If that continues to be the case, I won't be installing the 60-2 sensor, and would be happy to test code that supports this trigger scheme natively.
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

Be alert! America needs more lerts.
savagerocco
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Re: Challenge: add Audi "trigger wheel" to code

Post by savagerocco »

The pin doesnt need to be removed.... I just cut a groove in the starter mounting hole. I have the original sensors in place still I have another 5 cyl motor that I am building for my cousin as well...... and I have a twin turbo 32v DOHC audi project in the wings as well, along with a 944 turbo just aching for ms3.......
Brent Savage
life behind the zion curtain
90 audi RS2 20VTQ 6sp MS3, MSX COP and Sequential and now MAF
87 Scirocco 2.0 ABA 16v EIP tubular cast MSII COP
86 Audi 4K20VTQ MSII
90 Audi 90 sedan 3.6l DOHC V8TT (project car)
89 VW cabbie (bitch basket) 2.0 ABA Turbo MSII
elaw
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Re: Challenge: add Audi "trigger wheel" to code

Post by elaw »

Hey that's cool - I actually wondered if it would clear but since the car's together I have no way to check.

In my case I think it's moot - the setup with the OE sensors is working like a champ and if it ain't broke I have no intention of fixing it! :lol:

Best thing is Marc's going to let me return the crank sensor for a refund, so I can spend the $$ on a 3" downpipe instead. 8)
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

Be alert! America needs more lerts.
julian944
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Re: Challenge: add Audi "trigger wheel" to code

Post by julian944 »

Hi Eric,
I'am new here, but just wanna know if your stock sensors are working now properly.
Have you done any changes to the code, or anything which is not stock on your ms3. I wanna convert my Porsche 944 which uses a 130 teeth flywheel trigger and a second single pin on the flywheel for the ot-signal to MS3. But it is using no hall-sensors, instead I have standard vr-sensors.

Does anybody have some information about that?

Thank you for your help.

Julian Bosch
elaw
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Re: Challenge: add Audi "trigger wheel" to code

Post by elaw »

Julian,

Sorry for the slow reply... I missed your post here!

I'm using the OEM sensors with success now, but there's a key extra ingredient: I have a special "divider board" from Jean at jbperf.com (racingmini_mtl on these forums) that takes the signals from the two sensors on the flywheel, processes them, and outputs a signal which looks like that from a 45-1 tooth wheel. That signal is then fed into the Megasquirt which uses it (along with a cam signal) like any other missing-tooth crank wheel. In your case (I'm assuming you have the correct motor in your 944) the cam signal would be optional - it would be needed to do COP or sequential injection, but without it you can run wasted-spark and batch injection.

It's possible Jean might be able to modify his board (or actually the code in the microprocessor that's on it) to accommodate your trigger setup, in that case you could easily use MS3. If not, you're out of luck for now since MS3 can't handle that type of trigger natively.
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

Be alert! America needs more lerts.
racingmini_mtl
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Re: Challenge: add Audi "trigger wheel" to code

Post by racingmini_mtl »

The problem with the 130-tooth wheel (and the 136-tooth wheel) is that it's impossible to have a reasonable divider to get an integer number of degrees per tooth (actually an integer number of tenths of degrees). With the 130-tooth wheel, you'd need to divide by 13 (for a simulated 10-tooth wheel) and with the 136-tooth wheel, you'd need to divide by 17 (for a simulated 8-tooth wheel) . The 135-tooth wheel used by the 5 and 6 cylinders is nice because when you divide it by 3 you get a simulated 45-1 wheel with 8 degrees per tooth.

So, while it would be possible to do it, it would result in very low tooth counts. And with the way the current translator code works, it might also have an impact on initial sync. By the way, if MS1/Extra were used it would actually be possible to use a smaller divider (larger simulated tooth count) since the code doesn't use all teeth for timing so it doesn't have the limitation of the integer number of tenths of degrees. And I'm not familiar enough with MS3 code to know if this limitation can be (or has been) removed.

Jean
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jsmcortina
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Re: Challenge: add Audi "trigger wheel" to code

Post by jsmcortina »

On one or two of the custom decoders I've rounded the angle a little. This will have negligible impact on timing accuracy and allows the code to work.
(See Renix in MS2/Extra)

James
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racingmini_mtl
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Re: Challenge: add Audi "trigger wheel" to code

Post by racingmini_mtl »

jsmcortina wrote:On one or two of the custom decoders I've rounded the angle a little. This will have negligible impact on timing accuracy and allows the code to work.
(See Renix in MS2/Extra)

James
But that does require a dedicated mode and can't be used with a generic m-n wheel, correct? So a 26-1 wheel (130 divide by 5) and a 68-1 (136 divided by 2) would require a dedicated mode. Would it be better to add support for the original wheels directly in the MS3 code? Could you use 3 tach triggers?

Jean
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Re: Challenge: add Audi "trigger wheel" to code

Post by jsmcortina »

racingmini_mtl wrote: Would it be better to add support for the original wheels directly in the MS3 code? Could you use 3 tach triggers?
Jean
Yes that would be best and we already have support for 5 concurrent inputs in software when used for 4 channel VVT.

James
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savagerocco
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Re: Challenge: add Audi "trigger wheel" to code

Post by savagerocco »

This would be a nice addition to the ms3 lineup... I have a 20v 5cyl motor in my cousins car, but he only has an ms2 for now... darn college students, always buying beer instead of car pars...
Brent Savage
life behind the zion curtain
90 audi RS2 20VTQ 6sp MS3, MSX COP and Sequential and now MAF
87 Scirocco 2.0 ABA 16v EIP tubular cast MSII COP
86 Audi 4K20VTQ MSII
90 Audi 90 sedan 3.6l DOHC V8TT (project car)
89 VW cabbie (bitch basket) 2.0 ABA Turbo MSII
julian944
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Re: Challenge: add Audi "trigger wheel" to code

Post by julian944 »

Is there the chance that there will be native support of flywheel-triggers for the MS3 code in the near future?

Best Regards Julian
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Re: Challenge: add Audi "trigger wheel" to code

Post by jsmcortina »

Possibly.

James
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Re: Challenge: add Audi "trigger wheel" to code

Post by jsmcortina »

elaw wrote:I figure the VR circuit on the V3 board could be used for one crank sensor, the VR circuit on the MS3X for the other, and the cam signal could be routed through the opto on the V3 board to JS10.
It could.
My only concern is the value of C13 on the MS3X input 0.22u with a 1k input resistor. Works to ~7kHz. Even though there's only one reference pin per rev, I'd like it to respond in line with the flywheel teeth so say 22kHz @ 10,000rpm. If you were prepared to swapout that cap for a 0.01u I think we'd be in with a chance.

Getting Opti running today makes me more confident about the flywheel triggers.
How about PT4 for the third tach? It would require and external pullup, but otherwise offers an install with limited DIY inside the case. (It could be selectable)

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

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Re: Challenge: add Audi "trigger wheel" to code

Post by jsmcortina »

I wrote a first draft of the code last night. Just need some thoughts on the cam input and then someone to have a go with it.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

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elaw
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Re: Challenge: add Audi "trigger wheel" to code

Post by elaw »

James,

You're definitely right about C13 - I note with interest that the current schematics for the V3 board show C31 (the cap that corresponds to C13) as 0.001 uf - the V3 board schematic I've always used (megasquirt_ShemV3.00.pdf downloaded from somewhere) shows C31 as 0.22 uf and that's probably what's on my V3 board. So that cap will need to be changed also. One thing I can tell you from experience is keeping the phase relationship right between the two sensors is challenging - we'll have to see how the sensors function with the MS input circuitry.

Anyhow, if you have code available I'm happy to test it although it might not be until the weekend since I've got a lot going on and this is going to require some substantial changes to my MS box and its external wiring. I'll probably see if I can do some creative wiring so I can change between the new and current setups with a minimum of fuss.
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

Be alert! America needs more lerts.
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