Hey everyone, new to the forum and the ISF community here. Bought 08 ISF and absolutely adore the car.

So the OEM shocks were leaking (90k miles) and I replaced them with Bilstein's. The car drives better than being on bad shocks, but still bounces. Driving over medium size bumps on freeway I'd fly out of seat and hit my head. It feels unstable all the time. In comparison, my previous s2000 was also stiff and drives pretty harsh over bumps, but it was never "bouncy". I searched up and down but most answers point to shocks, which I replaced already.

Has anyone had similar experiences, or any idea what could cause the bounciness? Or does 08 ISF just drive this way? Really appreciate the inputs guys, thanks so much!

Springs: OEM 2008
Tires: factory size, BF Goodrich G Force Sport (came with the car, about 60% thread left)
Not yet had had alignment yet since the shocks replacement

 

I had an exactly same experience on my previous car (not ISF).
That car had all the OEM rubber bushings replaced with polyurethane Energy Suspension bushings, even with Koni Yellows adjustable shocks, the ride was pretty unbearable over any freeway dips rather than bumps. I was like the car pulled down and I was flying up in my seat. However, the car was never “unstable” rather glued to the road.

 

2011 ISF here and recently replaced 4 shocks about 2k miles ago. Replaced with genuine Toyota parts, 100% oem.

92k miles now, zero mods on suspension.

Rear end easily steps out on even mild mid-corner bumps, that traction and slip control activates all the time now. Have to pretty much tiptoe around the throttle unless the car is pointed straight. And if the road is even slightly rough while full throttle and going straight, the rear end will step out.

Not sure what’s going on, but could be alignment related. Didn’t have this unstable issue until shocks were replaced.

 

I did this mid December.
The OEM is so over damped that it causes harshness on sharp defects in the road. On the highway that gives it a more planted feel

so now you replaced the shocks with something with less damping and you get less harshness. However the suspension moves more freely.

my experience is that in step downs the car settles after one bounce.

On the highway now there are a lot of dips that load the suspension up a lot more than before with the overdamped OEM shocks.

I feel like that’s basically as good as I could hope for from an aftermarket shock.

 

What your experiencing is synonymous with the 2008 OEM springs and shocks..

Freeway expansion joints were horrible back in 2009 when I bought MY08 IS F

I solved this long ago with a mid range priced set of "street" coilovers.

Solved the bounce and cleaned up the wheel gap..!!

Joe Z

 

Does replacing the LCA with Figs or RR help? I have the RR USRS LCA’s am not experiencing bounce issues on the highways or ours are flat.

 

Not the issues we are reading about here. LCA fixes other problems with tire wear and stability under very hard braking from high speed.

 

If you want to fix your current issue sell your current suspension setup and get some quality coilovers. That will remedy most of your issues if not all of them. USRS will help with steering and stability especially under hard braking. Your traction issue mid corner will be a mix of tires, open diff and your current suspension.

 

On my IS-F when I had KW3 installed, I had everything set to loose/light and my car was all over the place

I had to tighten things down, I forgot how many clicks, and things got back to normal

I still had my height as high as possible due to potholes and general driveability

Very jealous of those who can drop their cars, Houston roads inside the loop are terrible

 

Come see us in the Midwest. We sell admission tickets to hike some of our potholes.

 

Hey man. I bought the car from you. Shes running great still but the suspension is the only thing that I hate. I've softened her up and took her back to stock settings but the roads here are punishing. Can't believe you drove this thing on Houston roads! Something about the soil in Texas shifts everything..

 

I'm glad the car is still being driven!

 

I was debating between RR racing coilovers and Bilstein shocks back then, but went with shocks for simplicity sake. Looks like I should have gone the other way. Ha! oh well... at least I know it's not something wrong with the car. Probably will switch over to coilovers later on. Appreciate all the inputs guys!