donistook

<center><img src="http://pictureposter.audiworld.com/1510/mvc-200f.jpg"></center><p>When the S4s are lowered, the rear tie rod no longer runs parallel to the car...this creates bump steer and changes the rear toe setting dramatically when the body leans or when going over bumps and dips. This can create undersireable handling.


This picture shows how we modify the rear control arm for bump steer. We fabricate a bracket and weld it to the control arm to lower the pickup point on the control arm for the outer end of the rear tie rod. We weld a small plate to the inner pickup point on the suspension carrier to hold the inner bolt solid (it is an oval hole on the stock arm). We make a tie rod tube and use R/H, L/H threaded rod ends. To adjust the rear toe...we just loosen the locknuts on the tie rod ends and twist the tube clockwise or counterclockwise to adjust for toe-in or toe-out.

The picture also shows the same type of adjustable tube we make for the rear sway bar. In addition, we replace the rubber lower bushing with a solid bushing that we make out of Delrin. This picture also shows a mounting bracket for Ap brake calipers that were on the rear of this car when it ran in Speedvision GT. For the Grand-Am Cup, these will be replaced with S8 rear mounts. Wheel studs are installed rather than using lug bolts.

Don Istook
ISTOOK'S MOTORSPORT SERVICES

xr4tic

Does any of this pose a potential problem?

I would think with the solid bushings and rod ends, it might pose a bigger problem.

donistook

We use the Neuspeed rear bar and did install their subframe kit. We regularly check the subframe and after two seasons of racing have had no problems with cracking. We also use extremely heavy rear springs...about 1400 lbs...so our car does not lean into the corners and does not need much swaybar. The solid bushings have had no adverse effect. Thanks for the question.

Don Istook