Best MEthod for traction control: Retard Timing, Cut Fuel, Cut Spark?

[Lurker27]

I'm looking at running a TCS system for my E30 megasquirt install...which of these is the safest for an FI engine?

[nickmpower]

fuel and spark

[Lurker27]

Won't cutting fuel result in a lean condition (bad for detonation?)

[Matt]

Reducing fuel will make it lean, cutting fuel will leave nothing to fire.

Retarding timing is fine if and only if you need a moderate drop in power for a very short time.

[nickmpower]

fuel and spark

I should specify that this should be done on single cylinders at a time as necessary. I think the race logic system does this

[bmwperson]

my right foot

[Oleg Coupe]

Timing retard is VERY efficient way. Our traction controller do it that way. It outperforms RaceLogic's cut-method, especially on 4 cyl applications.

Some logs how it looks can be found here (just check the pics):
http://www.turbo-garage.com.ua/garag...ad.php?3,33598
http://www.turbo-garage.com.ua/garag...ad.php?3,33173

[multiplex]

oleg, how does your box communicate back to the standalone for timing retard?

[Oleg Coupe]

programmable 0-5v output. For stock ECU most offen we send it to IAT pin and use IAT-Ignition Retard table like this for Mazda Speed ECU:



While no slip it sends 20C, when drive wheel slips - 40C...100C depending on required retard. For stand-alone you may have separate analog IN for ignition retard. If not - use IAT as for stock ECUs.

[Matt]

If you're using a stock ECU you can use the pin that the BMW traction control system uses, and tune the ECU's response just like BMW's engineers did.

[multiplex]

awesome idea using the IAT

can your box handle both VR and Hall wheel sensors?

[Oleg Coupe]

Yes it works with both.

BMW's engineers didn't design it as drag-race traction. It kills spin but don't allow you to drive with let's say 7% slip. Also for turbocharged engine closing the throttle is no-no-no. It didsn't works that fast and you lost boost. To keep fixed slip % you need modulate WTQ VERY VERY FAST.

P.S. there is some great ideas comes in your head deep night if you have big power rwd car in country without drag tracks

[jon volk]

Timing retard and boost control has put a handfull of cars down the 1320 on drag radials to the tune of 6.90s and 200+mph.

[Lurker27]

Timing retard and maybe spark cut makes the most SENSE to me, because they would actually keep things spooled all the way.

The solution I'm looking at doesn't have speed dependent or traction dependent boost control as an option unfortunately.

[Oleg Coupe]

We found that for best results you have to set per-gear boost to have about 25-30% more WTQ then tires can handle. Then just let the traction do it's job. For sure if you have twice or triple more WTQ then tires can handle then retard is not enought...but that's why gear based boost needed to keep WTQ closer to traction limit.

[jonesmechanical]

Having used Race Logic on 3 different car now with no reliability issues, and offers launch control and wheel slip infinitely adjustable up to 25% on the fly makes it a no brainer. Other than trying to tune the AEM for traction control, I haven't had any other experience other brands. And I don't read Olegs Lauguage. Would have been cool to research what he is talking about. I don't know what the point of 7% is. Thats what I use in wet conditions on the track.

[multiplex]

i can't wait to get my gear based traction control going.. i think this and combination with my race logic will be a total win.

[Matt]

Yes it works with both.

BMW's engineers didn't design it as drag-race traction. It kills spin but don't allow you to drive with let's say 7% slip. Also for turbocharged engine closing the throttle is no-no-no. It didsn't works that fast and you lost boost. To keep fixed slip % you need modulate WTQ VERY VERY FAST.

P.S. there is some great ideas comes in your head deep night if you have big power rwd car in country without drag tracks

Thats exactly right, but just because the BMW traction control system isn't designed for that application doesn't mean you can't hijack it's methods of operation to work with your own traction control system. BMW's traction control system is excellent for street cars in low-grip situations though.

[blackbenzz]

Ri tard