Poor man's Drag Anti-lag??

[quest49s]

I've had this on my car for the past year or so, and thought i'd share it with everyone else, to help some folks out or to have people point out the flaws in it.

First off my 91 TSi AWD has:
Completely stock longblock

Exhaust:
TEC td05 18g ported
ported 1g o2
ported 2g exhaust manifold w/ 35mm deltagate mounted on collector
2.5"->3" rre downpipe
3"catback with testpipe

Intake:
3" intake w/ 2g maf
2.5" ic pipes about -- 6-7ft of pipe
Spearco core
cyclone IM

I bought an MSD Dis-2 around 3 years ago(before dsmlink was widely popular or for 1gs, and really the only other means of a stuuterbox where standalone) mainly for the stutterbox and increased power off the line. With the 2-step set at 5,500rpm i was able to build around 8 psi at the line which was great, but started thinking ways to build more boost. Then i remembered the base timing wire which you ground to set your base timing, this retards the engine timing to 5* ATDC.

So how does this come into play? Like most other people who have hooked up a MSD stutterbox they use the factory clutch safety switch and an aftermarket relay to engage the stutterbox while the clutch is pressed.

So what i did was hook the stutterbox wire and base timing wire to the aftermarket relay so when the clutch is pressed the stutterbox is engaged and the timing is retarded, with this combo at 5500 i am now able to build 16psi at the line due to the less controlled ignitions helping to spool the turbo.

Anyone seen anything like this on a dsm before? Questions comments, and concerns are welcome. Couple of my concerns are: The stress put on the exhaust/turbo from violent explosions, and repeat cycling of the ECU between Base timing mode and normal operation every time the clutch is pushed in.

If there is something you want more detail on or clarified let me know,

And one more thing i don't quite understand myself, if the MSD-DIS 2 studder boxs works by dropping spark in cylinders to keep the rpm at a set range wouldn't the fuel go thru the cylinders and ignite in the exhasut manifold regardless of timing adjustments? Or maybe the waste spark from the #2 cylinder is igniting the #3 cylinder fuel at the bottom of #3 stroke? Perhaps that little bit of timing retard allows the gas to escape and ignite on the manifold?
- Also not sure if the fuel is igniting on the manifold or while the exhaust vavles are open on the wasted sparks cylinder???

Anyway let me know what you think.
Jon

 

[larsrya8]

Then i remembered the base timing wire which you ground to set your base timing, this retards the engine timing to 5* ATDC.

Actually, it goes to 5* BTDC.

 

[quest49s]

Actually, it goes to 5* BTDC.

Ah yes thanks thats what i meant, slipped through the proofreading cracks, thanks

 

[pneumo]

Neat idea! How violent and how far apart are the stutterbox pulses? If they're close together, like a quick 'nananananaa' sound, your turbo should be OK. If the pulses are spaced farther apart and hit harder, like a 'boom, boom, Boom' sound, beware. I remember reading about a guy on the DSM-ecu list who was playing with code to retard timing while on the stutterbox. He sheared off the turbine wheel. The hard and slow pulses of his stutterbox were too violent for his 16g.

 

[awdtalontsi1992]

Doing this in any form would be very hard on on your turbo and exhaust system. However it would be very benefical on the line. Most anit-lag systems actually retard the timing up to 40 degrees. The trick would be to maybe put a delay on the clutch switch. If you could delay the signal to the grounding relay then the computer would only cycle when the clutch pedal was pressed for over a certain amount of time. This combined with a simple switch would only let the timing delay work on launch. A push button on your steering wheel or shift knob would also work.

 

[larsrya8]

Doing this in any form would be very hard on on your turbo and exhaust system. However it would be very benefical on the line. Most anit-lag systems actually retard the timing up to 40 degrees. The trick would be to maybe put a delay on the clutch switch. If you could delay the signal to the grounding relay then the computer would only cycle when the clutch pedal was pressed for over a certain amount of time. This combined with a simple switch would only let the timing delay work on launch. A push button on your steering wheel or shift knob would also work.

What you're describing is called a "stutterbox" launch, which he already has with the MSD DIS.. What he's looking for is anti-lag, which works between shifts while going down the track. It's to help keep a large turbo spooled between shifts, and yes it is very hard on the turbine wheel. I don't think you can really do this without the ECU being actively involved, or if you used some sort of seperate timing computer (something similar to the S-AFC, except for the timing signal).

 

[PieEyedPiper]

I've had this on my car for the past year or so, and thought i'd share it with everyone else, to help some folks out or to have people point out the flaws in it.

First off my 91 TSi AWD has:
Completely stock longblock

Exhaust:
TEC td05 18g ported
ported 1g o2
ported 2g exhaust manifold w/ 35mm deltagate mounted on collector
2.5"->3" rre downpipe
3"catback with testpipe

Intake:
3" intake w/ 2g maf
2.5" ic pipes about -- 6-7ft of pipe
Spearco core
cyclone IM

I bought an MSD Dis-2 around 3 years ago(before dsmlink was widely popular or for 1gs, and really the only other means of a stuuterbox where standalone) mainly for the stutterbox and increased power off the line. With the 2-step set at 5,500rpm i was able to build around 8 psi at the line which was great, but started thinking ways to build more boost. Then i remembered the base timing wire which you ground to set your base timing, this retards the engine timing to 5* ATDC.

So how does this come into play? Like most other people who have hooked up a MSD stutterbox they use the factory clutch safety switch and an aftermarket relay to engage the stutterbox while the clutch is pressed.

So what i did was hook the stutterbox wire and base timing wire to the aftermarket relay so when the clutch is pressed the stutterbox is engaged and the timing is retarded, with this combo at 5500 i am now able to build 16psi at the line due to the less controlled ignitions helping to spool the turbo.

Anyone seen anything like this on a dsm before? Questions comments, and concerns are welcome. Couple of my concerns are: The stress put on the exhaust/turbo from violent explosions, and repeat cycling of the ECU between Base timing mode and normal operation every time the clutch is pushed in.

If there is something you want more detail on or clarified let me know,

And one more thing i don't quite understand myself, if the MSD-DIS 2 studder boxs works by dropping spark in cylinders to keep the rpm at a set range wouldn't the fuel go thru the cylinders and ignite in the exhasut manifold regardless of timing adjustments? Or maybe the waste spark from the #2 cylinder is igniting the #3 cylinder fuel at the bottom of #3 stroke? Perhaps that little bit of timing retard allows the gas to escape and ignite on the manifold?
- Also not sure if the fuel is igniting on the manifold or while the exhaust vavles are open on the wasted sparks cylinder???

Anyway let me know what you think.
Jon

very cool idea, not sure about the pro/cons myself, but just curous how long you've been doing this?

 

[quest49s]

What you're describing is called a "stutterbox" launch, which he already has with the MSD DIS.. What he's looking for is anti-lag, which works between shifts while going down the track. It's to help keep a large turbo spooled between shifts, and yes it is very hard on the turbine wheel. I don't think you can really do this without the ECU being actively involved, or if you used some sort of seperate timing computer (something similar to the S-AFC, except for the timing signal).

The ECU will need to be involved in the way i have it setup now, however as mentioned above(by someone else) the best solution as of now to keep the ECU from cycling between modes is to install a switch, to disengage the timing ground wire to the aftermarket relay.

Yes it is to help keep a larger turbo spooled however my 18g is far from large...the greatest benefit i see is at the line, being able to generate 8psi more then the stutterbox alone.

8psi @ 5500rpm w/o timing ground mod and 16psi @ 5500rpm w/ timng ground mod

Jon

 

[quest49s]

very cool idea, not sure about the pro/cons myself, but just curous how long you've been doing this?

I've had this mod wired up for about a year now and have had the MSD for about three, no problems with the ECU, turbo, or exhaust...However I'm not saying that this doesn't cause excessive strain on the turbine wheel and exhaust cause it deffinitly does just saying that i've been fortunate to not have any problems yet.

 

[pneumo]

I know it's a little OT, but I have to ask. How much is too much? I had good results launching at 5500rpm and 10psi with a 50 trim, and 12psi on a 14b. This is with a fidanza flywheel, which likes to launch at higher rpm, too. At some point you'll just get more wheelspin. You know that if you hold the throttle open longer the boost will keep building up. The longer it bounces off the stutter limiter, the more boost builds up.

 

[Steve93Talon]

This is an old trick, and probably not very popular for two reasons. 1, because it's hard on the turbo, and 2, because anyone with a turbo large enough to need anti-lag probably already has DSMlink or AEM or such.

 

[quest49s]

This is an old trick, and probably not very popular for two reasons. 1, because it's hard on the turbo, and 2, because anyone with a turbo large enough to need anti-lag probably already has DSMlink or AEM or such.

1)This is the first i've ever heard of it....if you can will you show me where others have written about it, i'd like to read what they had to say about it also.

2) Good point but this was purchased before either the EMS or DSMlink were popular for our cars.

8psi is the max i can get on the line(w/o this mod)... so no i can't just keep it at the stutterbox and continue to build boost, remeber the car is not at full power on the stutterbox it systematically cuts ignition to keep it at the set rpm point.