jayjy wrote:I have a question here. I just bought a mid-mod 240sx, it has a set of KYB AGX & Eibach , when I drove on freeway, when the speed reachs 50 miles per hour, then the car began shaking like a jumping horse. That feel is horrible, is that normal? According t o your post, it seems the problems should be the problem that caused by KYB AGX & Eibach, Right?
No...AGX/PK combo shouldn't cause that to happen at all. The AGX is, on its lowest setting, a slightly stiffer damper than stock. The PK has only maybe 20% stiffer rate than OEM springs. In other words, if that set was installed correctly, it should feel just fine.
Is the car shaking side-to-side, or are you referring to a "bouncy" ride up-and-down? Shaking at higher speeds is usually caused by wheels out of balance, bad tires, busted control arms and issues like that. Unless whoever installed that spring/shock combo really messed up, it should not be the source of your problem.
If you have the AGX all the way up to 4/8, you are going to get a very hard/bouncy ride on bad roads at high speed. Check the settings before you do anything else.