Thread: A few handling issues

Now that i have my car more settled in, i have been pushing it a little more. I have noticed a few things that are not that great.
Setup.
92 P10
AMR coilovers, 8K front 6K rear springs, Shocks on 2 of 8 front and 4 of 8 rear.
All ES bushings
Stock Anti-Sway bars
Rear hiem link lower control arms
SuperPro Caster bushings in from lower Control arms
SuperPro Camber bushings in upper link
Bump Steer eliminator kit
No PS, gutted rack, ES bushings
Self alignment in the front, slight toe out, 1/2* of negative camber
Rear aligned at 0 toe and 1.5* negative camber

First issue is if i hit a heavy bump while accelerating or turning the wheel will be slightly offset once the car is back straight, but it still drives straight. Then once i hit the brakes the wheel returns to the correct position. It does not happen very often.
A few ideas i have:
K member shifting. Still on the stock K member bushings, have poly ones but have not installed yet.
Steering rack play. New inner tie rod ends
Alignment issue. I have not had a good alignment since i changed a few things. I did my own just by measuring the front and rear of the tire. There might be some slight toe out, the wheel is straight, and it drives really well. No bump steer and does not wander. This seems to be the most likely to me.

The second issue is when entering a corner under deceleration there is an under steer condition, then accelerating quickly the rear end snaps around and feels really balanced. If i am heavy on the accelerator when entering the corner it does not snap around. Also if i enter a corner with light steering input then turn in more sharply it can also snap around, but i have to be cornering really heavily.
A few ideas:
The rear springs have a lighter part of the coil, this could be compressing then i am on the main spring? Might try adding a little more preload to see what happens.
Stock rear anti-sway bar not big enough to control the stiffer springs?
Stiffen the front shocks to slow weight transfer?

Other than that the car is generally very neutral and goes where you point the wheel. By far the best handling car i have ever owned.

I jacked up the car today and supported it with jack stands on the lower radiator support. Then i use the jack on several points of the K member and it is moving. I think the next step is to replace the K member bushings and see what happens. I increased the stiffness of the shocks to 3F/5R and the snap is even worse but it rides better. Once the snap takes place the car rotates very well though.

like the subframe bushings the one member makes on here.....

I have had the bushings for quite awhile, just never installed them.

I tore the car apart yesterday and noticed the bolts on the front lower control arm mount were loose, think this is/was the cause of at least one of the issues. I am still going to replace the K member bushings though.

Clarify for me please, K member is the sub-frame where the LCA and steering rack is attached to, not the cross member?

Correct. K member or subframe, they are one in the same.

Ok, now that I know we are on the same page, replace those POS. They are softer than a pencil eraser and deflect so poorly. It hurts handling, braking, and acceleration. Of all the bushings I have felt on all of these cars, those sub-frame (k member) bushings on a G20 are the most pathetic pieces of rubber I have seen used. It is a rather big job, rack has to come out in order to replace them but I believe it is the only way to do a P10 right.

I just finished it up installing the bushings earlier today and have the alignment close. I think there is a little toe in still but i did notice a difference in how the front end feels. During dis-assembly i found the real issue, 2 of the 3 bolts that hold the drivers side control arm on were loosed. I decided to replace the bushings anyway since it was almost out at that point.

I actually left the rack on and pulled it out as an assembly, i think it was easier than trying to bolt the rack back in once the k member was back in. I removed the lower control arm from the k member, removed the sway bar, header and flex pipe, shift linkage, removed the cross member, and slid it out. The hardest part was getting the K member back into place, all i had was a single floor jack, but it worked.

I took some twisty roads home tonight and came up behind a chevy truck going slower. He then tried taking some corners faster too, swerving between both lanes as i stayed in the right lane on his ass. Then when we got to a straight away i blew past him, he tired to speed up. Then on the first corner i dropped it down a gear and he ended up breaking hard before the turn and could not keep up. Funny how he even tried.

The car is very predictable now and still has some push in the front. I need to play with the shock settings now and maybe upgrade the rear bar.

Wonderful to hear that those silly sub-frame bushings were replaced and you seem much more confident in the car! Must be a blast to drive. Those AMR coilovers are rebound adjustable only, correct?

Yes, rebound only. I increased the dampening before i did the bushings and now the car feels more planted and does not bounce like it did. I might go up one more in the rear to see if i can get it to rotate a little more.

The car is fun every time i get in it, i love taking corners fast and now that it is so stable and predictable it is even easier.