I bought a set of used JIC FLT-A2 coilovers for my 2004 G35 coupe from a member/store on this board. Even though these coilovers had been on his track-only 350Z, he included a set of lavendar-colored springs that he said were the G35 springs for the coilover kit.

On the recommendation of JIC themselves, I got went to F1 Motorsports to have the coilovers installed. As I watched them work, they were obviously in a hurry, took four tries to get the right height, and never once adjusted the damping of the coilovers.

The problem is that the car now, IMHO, rides like crap, but I don't know if:
1) it was installed incorrectly
2) the damping needs to be seriously adjusted
3) I really made a mistake and bought coilovers that are way too stiff for me.

So, by "rides like crap", I mean:
1) When I slowly go over a speed bump, the front drops down so fast that my transmission or something connected to it hit the speed bump with a good amount of force.

2) On many sections of highway, the steering wheel shakes

3) On freeway sections that have frequent pavement breaks, my car shakes to the point of making me sick. I seriously still feel nauseous and might throw up before I'm done w/ this post.

I've driven several other types of cars w/ other types of coilover systems, and I've never had anything but great reviews for those cars, but none of them were G35s. This just doesn't seem right, but I don't know if I just made a stupid mistake by buying coilovers that are more track-oriented than street oriented. OR, do I just need to stiffen the damping level on the front coilovers?

Thoughts?

 

All FLTA2 springs are lavender color... like a light purpleish...

They are high spring rate springs usually for those...

few things you can do...

1. on the flatt part of the spring (at the top or bottom) you will have the spring rate printed on them... The spring rates are probably 10K / 10K possibly 10k / 12K rear if they were the hard version...

2. make sure there is no pre-load on the springs before the car is set on the ground since the suspension is fully case length adjustable... adjust height by adjusting the case length not the pre-load on the springs...

The suspension is going to act like that when going over bumps... sounds like it rids normal to me...

as far as on the high way, you may have some other suspension bushing problem that is coming into focus now that you have less movement in your shock / spring set up...

 

Thanks for the info! Turns out part of the problem was that the front driver's side was set to the softest setting possible, and the front passenger side was set to the stiffest setting possible. The guys at F1 are real winners... and I'm an idiot to trust them, and to not notice their mistakes.

I haven't been able to adjust the rears yet...