straycatt

Ok, so we all know that ASR is traction control.

If I recall correctly MOM (Manufacturers Owners Manual) says that at lower speed the computer is biased towards getting the car going in a straight liine...traction. At higher speed the bias is more about maintaining control...handling. Which brings us to the point...When you turn it off. you're on your own, control wise. But what else does it do?

Does turning it off alter timing and/or fuel mapping? Maybe everyone else already knows this, but I've never seen it discussed on the forum.

The reason I ask is, I was curious about how badly my Nitto 555 G2's flat spot after sitting for a few days, so I put the rear end up on jack stands and fired up the engine. In first gear I noticed that a gentle blip on the gas would activate the ASR...makes sense as the front wheels aren't turning so the computer kicks in the throttle jammer.

This is where it gets interesting. ASR on, the engine is idling at about 800 rpm. Turn off the ASR, idle jumps up to around 1000 rpm. What's up with that? Is the computer going into a different performance map, or maybe just dumping vacuum causing an increase in idle speed? Anyone?

1993C4LT1

That's weird. It shouldn't do that. I honestly have no clue. Turning it off is simply, being able to spin the tires when they do want to break loose.

FAUEE

I didn't think the c4 ever got a fancy air system, I thought that debuted on c5.

Regardless I think what you're probably seeing is a slight change in tension on the throttle cable by deactivating ar. Remember, all air really does is shove the cable and thus throttle body shut when it detects slip. So its probably more mechanical than anything.

1993C4LT1

Yeah as far as I know, no C4 has active handling. It was even an option on early C5s.

novaks47

The 96's had a Bosch system, using one-off Delphi shocks that are long gone. That system was the more primitive precursor to the C5 system. It had ride select, which was three user selectable modes, and each mode had a range of rates it would use. It was very much active handling.

vader86

It can apply the brakes itself and change timing, I think that is all it was designed to do then. I'd have to look into my SAE papers from the time to see exactly, but i dont think it does anything else.

pacoW

I have a '96 and this is how it works for me. Never felt the ABS module trying to stop the front (or rear) wheels, compared to other cars I have with stability control. The only thing I feel with ASR is reverse (opposite) pressure on my right foot from the pedal.

FAUEE

That's an active suspension. Active handling refers to a stability control system on later corvettes.

1993C4LT1

Correct.

novaks47

Ah, I thought STM was separate.

straycatt

Some food for thought, here. Thanks.
I know the ASR has control over throttle...and to some degree (degree...get it?) I believe timing. The car just seems to have a little more omph when ASR is off. I guess it's time to start digging thru the FSM.

Again, thanks for the input...

Oh and by the way....yes the G2's flat spot big time. lol

rocco16

For the 1996 C4, the FSM calls AIR by the term Traction Control System (TCS). It says this:
"The Traction Control System uses engine spark retard, throttle close-down, and rear brake intervention to provide enhanced acceleration and vehicle stability. The system enhances the following general vehicle characteristics: directional control, traction, and maneuverability. The TCS accomplishes these goals through use of wheel speed information, as well as the following:
Vehicle speed, to give traction priority at low speeds and directional control priority at high speeds.
The speed differences of the non-driven (front) wheels, to detect a cornering maneuver. Directional control has priority when cornering."

That's not the whole of it, of course, the system is really very sophisticated for its time. Bottom line: at least the 1996 Corvette had a basic electronic stability control system in place.

johno504

On my 96 , I can't get the ASR to turn off. don't see much reason to fix it , as car is only street driven. Am I wrong on this ?

straycatt

Well for me, it's fun to be able to spin a wheel once in a while. There's a corner by my house that has very smooth cement. With ASR off, I can do a nice power slide around that corner. And then there's the power thing. If ASR retards timing, you're not getting as much power as should be available.

Dealers choice.

Disclaimer: The above is written for entertainment purposes only. I always follow all traffic laws and rules of the road. Especially when driving the Corvette.

Bigpoop

yeah baby. That is why I drive a CORVETTE and not vw crossover thingy

93Rubie

I run ASR off all the time. Its useful for wet roads and such. Not much else. It does work quite well however for a old system. There IS a YAW component to the system its not active handling but it does incorporate a yaw sensor and uses this to control brake inputs in a ASR event. At low speeds the brakes can and WILL intervene. Higher speeds just throttle and timing reduction.

JimLentz

http://www.lwta.net/photos/Corvette%...s%20Manual.pdf

JimLentz

It may be applying the rear brakes.

drcook

Yep, I got rid of the d*mn things. No way I am going to go drive 8 to 10 miles to warm them up just to be able to get on the highway if I let the car sit for a couple days. Here in NE Ohio we can get 3 or 4 days of rain and those dang Nittos would shake the car like it had square wheels.

NTB warrantied them out for me.

1993C4LT1

Weird. My g2s never did that.