964 C4 suspension advice?

[gardoni]

I've got a '90 C4 with about 90k miles on it. Rear suspension feels overly stiff. Less comfortable than a '91 Targa I test drove a few months a go with H&R coilovers. There's a definite solid rear thump on every bump/seam in the road and I can barely move the rear suspension if I lean on a rear fender. I imagine the car has the original springs and shocks, possibly lowered- looks lower than stock.

I'm leaning towards replacing the rear suspension with new stock components, but am curious what others think. Do the stock springs wear out? If lowered, does the suspension get stiffer? When/if I replace the rear springs and shocks, I'm guessing I'll need an alignment? This is a weekend driver and won't be tracked.

Many thanks.

[Bill Verburg]

You might want to confirm what springs and shocks you have now

'90 oem rear springs for a manual trans 964 will have blue paint stripes
stiffer M030 will have green paint stripes

[Don Plumley]

Originally Posted by gardoni

Do the stock springs wear out?

Not that I'm aware of.

Originally Posted by gardoni

If lowered, does the suspension get stiffer?

Shorter springs are typically stiffer due to shorter length and design.

Originally Posted by gardoni

When/if I replace the rear springs and shocks, I'm guessing I'll need an alignment?

You should probably replace fronts and rears together. You'll definitely need an alignment for the front. Not too worried about the back.

Originally Posted by gardoni

This is a weekend driver and won't be tracked.

New shocks and stock springs should work well for you.


Question: Do you have stock size wheels?

[gardoni]

Bill, Don-
Thanks for the info. I've got stock Design 90 wheels and intend to stick with them for a bit anyway. I pulled a wheel to look, but don't see any stripe- blue or green. Tried cleaning off the spring a bit and it looks to be black.

Am I correct that the lower spring seat adjusts pre-load and ultimately ride height, and that moving this up will create both a stiffer ride and a higher ride height?

Thanks again.

[Bill Verburg]

It looks to be stock 964 rear to me, springs do tend to sag a bit w/ the years but not go bad, harshness could be tires or bound up shocks, I would replace the shocks w/ Bilsteins or stock oems to restore stock ride qualities, also be sure to inspect and replace if necessary all the rubber bushes. If the tires are more than 5 years old, they shopuld probably be replaced too

[davisriley]

I found that my car got more compliant when I replaced my tired stock suspension with H&R reds and koni adjustable shocks, when I turn them down. So you may want to try and drive some cars with different suspension, and see if any of them feel okay to you.