Oversteer...

[Mark B]

Hey everyone,

I have noticed that my 91 RS has a fair amount of oversteer. The rear wheels let go way before the fronts even think about loosing traction. What are the possible causes of this? Is this just how F-Bodys handle? My setup includes:

Eibach Pro-Kit Springs
Polyurathane Bushings
Stock "RS" sway bars
KYB GR2 shocks/struts
Sub-Frame connectors
3-Point Strut Tower Brace
Spohn Rear Control Arms w/ relocation brackets
Kuhmo Ecsta 245/50-16's on all four corners


Now I recently added 36mm/24mm WS6 sway bars and upgraded the shocks/struts to Koni Adjustables. I havent had a chance to test the new setup, but I am hoping that these new additions have corrected the problem. If I find that I still have oversteer, what actions can I take to get the car more balanced? I would think that I need to loosen up the rear end or stiffen up the front. If I recall correctly, drifters use a really stiff rear with a soft front to get the car to oversteer. I would want to do the opposite. Correct?

I know my tires suck, but since all 4 tires are the same, I dont think that would cause oversteer? Would it? I would think it would just take traction away from all 4 corners.

How about my rear control arm relocation brackets? Are they possibly adding to the problem?

Thanks for the help,
Mark B

[Joe 1320]

You have the basic idea correct. If the springs/shocks/swaybar in the rear are too firm, it will cause the rear to swing around first. It's a balence that must be dialed in by different combinations front to rear. increasing the rate of the front bar could help provided you don't up the rate of the rear bar as well.

[Wild Willy]

@nd that- I stiffened the from sway bar with a 32MM unit from a '99 WS6, left the rear at 19MM- my car plows (understeers) big time on the auto-cross type courses- even when I goose the throttle trying to break the back end loose and rotate it, the front just pushes

Or course, at higher speeds, particularly when firm upshifts occur, the back end can get a little squirrely...;^)

I have some photographic evidence- but 600kb is too big- and I don't have the tools to shrink a photo of my car with the front tires rolled over onto their shoulders down small enough to post- pretty funny, as long as you aren't planning on going through the cones fast....

[Joe 1320]

@nd that- I stiffened the from sway bar with a 32MM unit from a '99 WS6, left the rear at 19MM- my car plows (understeers) big time on the auto-cross type courses- even when I goose the throttle trying to break the back end loose and rotate it, the front just pushes

Or course, at higher speeds, particularly when firm upshifts occur, the back end can get a little squirrely...;^)

I have some photographic evidence- but 600kb is too big- and I don't have the tools to shrink a photo of my car with the front tires rolled over onto their shoulders down small enough to post- pretty funny, as long as you aren't planning on going through the cones fast....

If you swap in the 1LE 21mm rear bar, you can induce oversteer two different ways. By lifting the throttle, or by punching it. My 94 is set up with the 32mm front and the 21mm rear. I can alter my line in a corner by lifting the throttl, essentially engine braking. It will bring the rear around a wider arc (oversteer) and when I have the correct line, I reapply the throttle and the rear comes back in line. It's real handy. That being said, throttle induced oversteer can bite the inexperienced driver that's why the factory engineers the suspension to push through a corner as slowing down will correct the line and tuck the nose in. If oversteer was engineered in by the factory, too many people would kick the tail out by backing off the throttle and there would be serious problems for the unsuspecting and inexperienced. It really is a delicate balence.

[TraceZ]

the majority of your cars handling is determined by the tires. You can mess with the suspension until the cows come home, it will still handle crappy if your tires are bad. You say you have crappy tires, I'd say start there. I've heard great things about the new Firestone Firehawk Wide Ovals.

[Jeff_in_Atl]

Since you have Konis try adjusting the rear shocks to be looser.

One thing that many people don't think about for handling is the rear differential. This would be costly but switching from a limited slip to a Torsen would help the oversteer too.

[Mark B]

My entire rear is out of a 99 T/A. Gears, differental, brakes, everything. What kind of differentials did 4th gens come with?

I have all four konis on the softest setting right now. Maybe I could stiffen up the fronts. Tires are getting upgraded this winter (Hopefully with new wheels too!)

[Jeff_in_Atl]

My entire rear is out of a 99 T/A. Gears, differental, brakes, everything. What kind of differentials did 4th gens come with?

I have all four konis on the softest setting right now. Maybe I could stiffen up the fronts. Tires are getting upgraded this winter (Hopefully with new wheels too!)

98-02 F-bodies except Firehawks and SSs came with the Torsen. That's good for handling.

Yes play with the shock valving.

[Jeff_in_Atl]

Read this article http://www.koni.com/_cars/_general_i...ndersteer.html