My 94 has, what I feel to be massive oversteer. It is mainly all stock with the rear end lowered 1" and GY GSD3 255f/285r. Any suggestions on what can be done to help it out a little or is this just the nature of all C4s?

 

Never came across a basically stock C4 that oversteered unless the alignment and/or some of the suspension components were fubar'ed.

 

I had it aligned last summer, but looking at the rear tires, the tops of the tires are tilted inwards a little.

Would this cause the problem? What should be the specs on an aligment for this car?

 

How do you know that it has a tendency to oversteer?

I mean, unless you are driving your car near its handling limits, like say at track, how would you know? The C4's handling limits are pretty high that's why I say "at the track" because to reach those limits, you would have to be going pretty fast. Maybe you are experiencing the dreaded rear wheel bump steer?

In any case, the C4's are tuned to understeer a bit first to warn you of impending loss of tire grip. And the only time it will then oversteer is with judicious application of brakes while cornering hard or with throttle (like drifting only the rear whips around).

 

I know because thats what it does when I drive it hard through corners and bends and thats why I would like to know how to correct it. Trust me this car has NO understeer.

 

Okay.

So when you are cornering hard and you begin to loose tire grip, you say the rear of your Vette begins to come around like it wants to make a 180? That's what oversteer means. I just want to make sure you are not experiencing rear wheel bump steer. If your C4 is indeed oversteering like we described above, something else is wrong with your car's suspension. That's because C4 Corvettes are not tuned to oversteer at the limit unless you hit the brakes hard or floor the throttle and you go into power oversteer.

The correct way for your C4 to handle is when you near the limit, the car will begin to understeer a little (the front end starts to push a bit) making you run a bit wide. YOu correct this by lifting the throttle a bit, which will tighten your line.

Under normal circumstances, you eliminate a car's tendency to oversteer by putting a larger rear sway bar. But your C4 should already have big sway bars front and rear.

 

What you have is negative camber in the rear. Whether or not this is helping or hurting is a function of the rest of the alignment. You can't eyeball it. You need to actually measure it.

Specs for your car are in the Factory Service Manual. My specs are for road course use that work with my suspension setup (ie aftermaket shocks, different sway bars, bushings, milled spacers, etc) so it wouldn't do you any good to use what I'm using (and a stock C4 can't dial in as much camber in the front as I'm using anyway).

An otherwise stock C4 on tiny 255 front tires shouldn't oversteer unless the alignment and/or suspension components are fubar'ed as I mentioned before. I'd say it needs to be put on a lift and inspected as a starting point.

 

Check the bushings. If they are worn out(15 years is a long time,) it can result in toe out of the rear under hard cornering and snap oversteer. It happened to me at the exit of the carousel at Infinion full throttle in third gear a couple of years back; a 360 degree spin coming to rest in the proper direction, I still can't believe I didn't crash into the wall. Changed every bushing on my car to poly a week later and that was the end of that problem.

 

If you really think you have oversteer, inflate the front tires a few pounds higher than the rears. This will help, again, assuming you do really have oversteer. Do check the alignment.

 

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