hkiang

Anyone have any rear suspension recommendations to cure what feels to be a wiggly rear end in quick left/right transitions? I have a 1994 Carrera 4 (widebody) wearing 18" Speedline for Porsche wheels and 285/30/18 in the back. Suspension-wise, it has Bilstein PSS9 coilovers, but otherwise is box stock. The car only has 30K miles on it.

I wouldn't be surprised if the additional weight/grip of the rear wheels/tires is causing/exacerbating the (inherent) unsettledness, and possibly warranting a larger rear antiroll bar. Then I did read about how some people change the rear drop links to eliminate some play in that assembly which allows for roll. Is it s a rear sway bar issue? Is there anything in the rear suspension that can distort causing changes to the toe?

For this discussion, let us assume that the car is properly aligned. (I believe that it is.)

Thank you.

Vandit

Check the condition of the bushing on the spring plate where it meets the car's unibody. Mine were torn to ****.

I swapped them out for the ERP 935-style spring plates that have a spherical bearing on the end and no rubber. They're lovely pieces but they'll set you back some $, but nothing like the price of replacement OEM spring plates.

Zingari

Its not engine movement caused by worn mounts is it?

Vandit

Also, by the factory's design, the bushing on the spring plate is engineered to be softer than the outer trailing arm bushing. This way, under braking, the rear will toe-in and increase stability. This is the Weissach effect.

ghhally

What's rear ride height vs. front? Some rake dialed in? Try to lower the rear end and see how the car feels?

Lemass Automotive

What tyres are you running. I had this issue with some non n rated tyres. I fitted some n rated continentals and it was perfect again

lateforlunch

I had the same problem and found my rear sping plate bushings to be shot like Vandit mentioned. Installed ERP items and its been a lovely drive ever since.

hkiang

Worn spring plate bushings. I'll check those. But the car is a low milage leader. I doubt they are damaged but I will check those.

The tires are Bridgestone re050a pole position.

The car is lowered with a slight rake towards the front.

Thank you, guys!

H

hkiang

Below should give you an idea of the car's stance.

NineMeister

Tyre pressures?
Geometry?
Corner weights?
Same wiggle right to left as left to right? (if not, possible damper fault)

hkiang

Just made an appointment to have a new alignment done, check the spring plate bushings and see if I can't find a bad damper.

But I guess my question is these cars are not supposed feel wiggly and that I should be able to run such a heavy and wide rear tire without it feeling so unsettled in the rear?

Thank you guys!

H

jack.pe

+1 on engine mounts... you upgraded them to semi solid? checked if worn? using RS mounts made my car feel much more cohesive

Earlydays

Absolutely