DMGroh said:
I was under the impression that my 96 LT1 ASR was similar to "positraction", but it is not. I still have a locker rearend, and I thought that ASR merely reduced the throttle input (as you take off from a dead stop) to minimize the rear end from slidding all over the road (I can do that myself by just getting off the gas). But as I read different posts and references to auto-cross, I'm beginning to think the ASR also functions while underway at speed. Does it fire the brakes at all 4 corners like the stabilitrak on my new Surburban, or just the 2 rear brakes?
Have I got this backwards? Any help would be appreciated!
"ASR" (acceleration slip regulation--a dumb name) is "traction control". If is not "positraction" (Chevrolet's older trademark name for limited slip differentials).
ASR reduces rear wheel spin in a three-tiered manner.
1) spark retard
2) throttle opening reduction.
3) rear brake application (below 40mph only).
ASR on 92-96 does not operate the front brakes, only the rears. Also, ASR is not a stability enhancing device, ie: it does not use rear differential braking to control yaw, it only applies both rear brakes to control wheel spin.
On slippery surfaces, ASR can react to wheelspin and control is faster then most drivers can react.
Tuna mentioned some posts I have made in the past about C4 ASR and modified engines. The nature of technology in the early 90s, when that system was introduced, is that it is part digital and part analog. That, coupled with the software technology of the time, has the first gen. ASR unable to adapt to engines with significantly higher torque output. The result is that, on an engine with, say 15-20% more power, when ASR works, it's going to feel less invasive and its "threshold" will seem higher. When my 95 ZR-1 was stock, the ASR's OE cal. was, IMO, quite aggressive and many others who wrote about Corvette in the late C4 era felt the same way. Admittedly, it's understandable that GM would do ASR that way the first time because it was such new technology in the early-90s. Now, with my LT5 at about the 500hp level, ASR is actually more useful in controlling wheelspin during hard acceleration. In fact, in all but dragstrip starts, I leave it on and....just floor it. In good air, the car will fry the tires right about where the engine gets peak torque and then, ASR steps-in and takes out just enough spark or throttle to stop the wheelspin but not bog the motor.