Help with Coilpack triggering?

[T3Bunny]

My original plan was to run a 1K Ohm resister from the Negative side of the LED, to the 5V side of the LED resister (As a pull-up), and then run a wire from the Negative side of the LED to my factory coilpack (And then do this for all 3 LEDs for my factory VR6 wastespark coilpack with ignighter built in).

This plan will work fine and is exactly what I have done on the three I have done. Treat it just like a 7pin bosch module with non-inverted spark, and fixed duty of 50%. I also have a msq if you need it toss me an email.

[Keithg]

Keep in mind that Bosch used a 60/40 wheel in the dizzy of cars which used this module. If you want me to measure mine again and figure out which way it needs to be, I can. Also, I feel this needs to be addressed in the code to make it right. Currently the code is written to take 50% of the time between triggers. To get 75%, it takes another 50% of that result to get a 25% value. To make it work as 40%/60%, it would take a division instead or a shift. Pretty do-able, but it has not yet been done that way.

Anyway, this means that the 50% or 75% dwell trigger is actually not 'correct' for a Bosch module and it will not calculate dwell properly. In my experience, it will 'work', but will not give as strong of a spark as when you allow MS to control dwell. This was with the MS1/E 029 code on a V2.2 board. I have never seen anyone do a trace of this, but I have measured the trigger wheel in a Bosch dizzy and it is definitely 60/40 and not 50/50 or 75/25. Based on how this module works, to get appropriate dwell, it needs the correct trigger cadence. I *think* this is why there has been spotty record of the dwell control Bosch modules and also why the dwell control modules are not suggested for MS2, but the dumb Bosch modules are.

KeithG

[T3Bunny]

Keith I am compleatly lost on what your talking about here.

These setups do not have a dizzy. We are discussing the VR6 with a wasted spark coilpack and a 60-2 VR crank trigger setup. Referance was made to the 7-pin only because he was wondering if thats the correct setup scheme as far as ECU mods and the like.

I *think* this is why there has been spotty record of the dwell control Bosch modules ...KeithG

I have installed and tuned countless VWs running these distributers and the 7-pin modules. This setup is reliable to a fault and I have never seen a single failure. I have tuned and maintained several turbo cars still running these modules and the only issue I have ever seen is spark blow out above 20psi. ANd this is easily cured with an upgraded MSD coil and properly gapped spark plugs. Spark plugs actualy doing more than the coil.

As for changing over to direct coil control, I have seen nothing but failures....

Not saying that measuring and verifying this wouldn't be a good idea though... If a 60% dwell would be better, then whats needed to impliment this in the code and is this something your capable of? I have multiple cars avalible for testing this on. And in fact I am off to put an engine into a rabbit tonight and it will be on MS by the end of the week.

[Keithg]

I am saying this based on my own experience. Initially when I set up MS on my car, I ran 'fuel only' and used the stock bosch ignition system to drive the spark (dizzy and -139 module). I was able to run pretty high boost and had decent drivability (accel). When I switched to MS control with the -139 module (module controls dwell) it was fine except at boost above 10 psi. It was acceptable, but not as strong as previous. This is with a very similar to stock timing curve. To accommodate this, I had to fatten up the mixture to keep spark alive. When I switched to a VB921, I had much better spark, especially at higher boost. I was able to pull some fuel out of it. Also I was able to make accel enrich work a bit better. Subsequent to this, I went to wasted spark then COP. It has been a while since I have run it, but I suggest either a coil driver IGBT or a *dumb* Bosch module (-124) with MS controlling dwell. This is all with MS1. With MS2, you can select any %age, so a -139 should work better, but I have not verified this and it is no longer listed as 'supported' as an ignition driver type for MS2 or MS1.

I know that the pattern that the module sees is 60/40 because I measured it and I am supposing that the dwell is more *correct* if it gets this cadence. That would be why it worked fine as stock, but not as well when MS was driving it. I never checked it as I was going to COP, anyway, so it was not a priority.

You are free to disagree, but my experience is that a -139 module does not work as well with 50% or 75% dwell under MS as it does with a Bosch dizzy driving it. The only difference I can see is that the cadence is different and I am supposing that it would work better if it had this cadence. If you are suggesting a Bosch dwell control module for a single output or W/S setup, I would verify with a scope what the cadence is on a stock install and program the MS to run that cadence so that it can calculate dwell properly.

As for doing any code modifications, Yes, I can do that, but I do not suggest it as having MS control dwell is better, IMO, than relying on the dwell control modules. If you want to try a variant with this in it, I can probably roll something, but you'd have to test it as I have nothing to run it on.

KeithG

[Budget Monty]

I see what you are saying Keithg, now I am beginning to wonder what the input dwell is from the factory distributorless VR6 ECU to the factory coilpack with internal smart dwell ICM. My car ('91 GTI with distributor VR6, getting swapped to distributorless with MS swap) of course is gonna be of no use of course for testing. T3Bunny, do you maybe have acces to a coilpack VR6 car that runs that is still on stock management to get some factory dwell numbers from?

[T3Bunny]

You are free to disagree, but my experience is that a -139 module does not work as well with 50% or 75% dwell under MS as it does with a Bosch dizzy driving it. KeithG

I have never setup a VW on fuel only, so I will happily take your word on this. Without a before and after, and say a KV terster on the OE versus the MS spark setup, the tuning would mask almost all these issues. This would not be an easy thing to spot. I did notice spark blow out occuring under REALY hard acceleration between 16 and 20psi. this was solved by simply dropping the gap on the spark plugs from the delivered .45 down to the .23-32 as per the Callaway Turbo Installation manual. I also was runnign a MSD Blaster 2 coil that I am sure would have been happpy running more dwell...

I would be VERY happy to check out a modified code and will probally have this latest project online by next weekend for a test bed. Again the main reason I stick with the Bosch modules is a simple issue of reliability.

T3Bunny, do you maybe have acces to a coilpack VR6 car that runs that is still on stock management to get some factory dwell numbers from?

I may have access to one. Lemme see what I can come up with but it might take a while so don't hold your breath lol.

[kingtal0n]

I cant see any of the pictures. I am trying to setup a 2001 VR6 Jetta on MS-2 now. The ignition is the most difficult step for me. I am not sure how to set the ECU, the manual might contain the info but I am new to this ECU completely, I read it says "On the V3.57 board it is usually easier to solder the jumper wires for spark A, B, C to the underside of the DIP40" I am not sure if this applies to me.