Has anybody played with the traction control on the EMS? I'm curious what their impressions were. I don't believe I would want to go through the trouble of enabling/tuning it. But I'd be curious if anyone has had any luck with it.

My thoughts are that with how it does the fuel/ignition cut (i.e. like a rev limiter) that if it was used a lot and you still had a cat installed it could foul the cat quickly. Or at least it seemed difficult to get a 2 step working without going way rich from my not so expert experience on it...

 

Actually Gary, you can implement traction control in a variety of ways. The most common is to pull ignition timing, but not cut. So, just like you see a power loss pulling 5 deg of timing on the ignition map, you'd see the same loss pulling 5 deg of timing when traction control kicks in. By pulling, say, 15-20 deg of timing you could cut power substantially (25% or more). At that point, you'd probably start to run rich too, so you'd want to pull some fuel.

The idea though is a smooth ramp down of power rather than simply cutting it off (which you could do should slip become too excessive).

UL

 

UL,
That makes sense, and it does have a lot more control over the rev limiter. So you would pull timing first, and then start pulling fuel as needed I take it while watching the O2? Have you used it on anyones car yet? I have a feeling it takes a long time to get this dialed in.

I would also think it would take a while to get used to letting the traction control do it's job, and keeping the foot on the gas. I've never driven with traction control, so it would be interesting to try sometime.

Thanks, Gary

 

Its in development - with TC there is a substantial liability issue if you get it wrong and someone has an accident. Not sure how I want to handle that.

UL

 

Out of curiosity, what sensors will you input into the AEM to let it know to retard timing or take away fuel? I understand how it works with a car that comes equiped with traction control, but the S2000 doesn't have that feature built in.

 

Should be able to get what you need from the ABS sensors.

 

ABS speed sensor wiring does not go through the stock PCM. The ABS control unit is built into the Modulator under hood. If the AEM needed wheel speed sensor input, you would have to wire it from there.

 

All you need is engine acceleration rate (IOW, the rpm input). That and the vehicle speed sensor (VSS) so that the EMS knows what gear you're in.

Knowing that, you tell the EMS what the maximum allowable engine acceleration rate is in each gear and you're done. This is the same basic setup used (illegally) in many forms of racing (NASCAR, formerly F1, etc.).

UL

 

Yah, I can see the issue being getting it tuned on a car, and then trying to make that work on another car with different variables... Might just have to do something with a base setup, and then tune it on a track day to get around those differences to limit chances of it being setup wrong.

 

While ignition timing retardation works in race cars, it is how most oval track (usually illegal) traction control systems work, it doesn't work for street engines.

When you kill the timing you send extra fuel to the cat, overheating it. Street systems cut fuel. When it is leaner than 25:1, their is no ignition. And it doesn't hurt the cat.

There is a traction control system by the same people who make the GPS performance measuring system. Their web site explains it.