996halfgt3

Squeak,
I meant when it runs over bump at high speed the rear leans left then lean right pogo right left or left right. It doesn't soak up the bump and doesn't remain flat.
Thanks.

Squeaky

Again, more specificity would help. What was running over a bump? And what speed? How big was the bump? What inputs where you giving the car? What dynamics was the car undergoing?

If a bump doesn’t get “soaked up”, it would suggest that the springs or high speed compression is too stiff, but then it “pogo sticks” which suggests highspeed rebound and/or compression is too soft. some amount of ‘pogoing’ is “normal” (depending on the goal) as highspeed damping ratios are usually pretty low (so that it can absorb bumps and dips). Unfortunately PSS10s don’t have discrete highspeed adjustment, and I don’t know whether the adjusters affect highspeed damping. You can try stiffening the dampers to see if that will improve the bouncing. If not, you can try using softer springs. Another thing is to soften the rear roll resistance in other ways, such as your roll bar. But again, some of this is contingent on the details of the situation that are missing (see first paragraph)

jgiannone

You may be running too low a tire pressure in the rear. I don’t think that’s the problem, but it’s worth considering. It looks to me like the tire is toe out under loading; check all of the rubber bushings in the rear to ensure none are deteriorated. If the rubber bushings are the weakest link and deflect under load, you may be getting all sorts of toe changes.

De Jeeper

I have been seeing "loose" suspension issues more and more in the 996 forum. Bottom line is our 996 cars are all about 20yrs old and all the suspension rubber has aged out. It doesnt really matter how many miles r on your car. It may be time for new coffin arms, tow links and forks. Replacement parts from trw are not that expensive. Also as weird as it may seem worn motor mounts can cause all kind of rear end issues. The exhaust tips should only be a 1/2" under the bumper cover.

996halfgt3

De Jeeper,
What’s TRW? The engine mount is original 18 yrs old and 25k miles on it. The exhaust tips are perfectly in place. Do you think that it might can be bad? If the rubber bushing turns out bad, which type of bushing would be good for replacement if handling performance is the priority.
TIA

Squeaky

its likely the bushings need replacement. Even when new, they can cause undesirable handling issues. You can replace them with stiffer or solid bushings if performance is what you’re after. Places like tarett, RSS, or elephant will probably have something. I find entire control arms a better proposition than just bushings though.

This won’t fix your problem if you don’t replace the tires, or if the car is not already set up right

De Jeeper

google is your friend.

Stock stuff is fine but if u want performance/race parts u will give up comfort. There is a ton of aftermarket support for the 996, you just have to search. My car has stock gt3 lower control arms, a bunch of rss heim joint links and terret toe bars. My car is a little rough on lowered springs but not bad and it tracks pretty good for not having coilovers.

https://www.fcpeuro.com/products/por...er-trw-997kit1