So i just installed the eibach pro kit monday using my stock front struts. aligned the car right away i set the camber adjustment to -2.2 in the front and -2 in the rear, caster remained at factory specs, and toe was off so i set back to factory specs. 5 days later (saturday) i rechecked the alignment since the car has been lowering by driving day by day because the springs were new and settling in to the ride height its sitting at now which im estimating was a 1.2" drop. the front left caster reads 9.3 (out of spec) and the right front caster reads 8.5 which is closer to spec but slightly off. is caster something i should worry about fixing?? if so how do i? im told caster is not adjustable for g35s. but i do have a godspeed front and rear camber kit. dont know if that has an adjustment.

 

Caster is not adjustable from the factory, although with many aftermarket camber correcting / adjustable upper control arms it is. I don't know if the godspeed allows this or not, but SPC and SPL both do (highly recommended using one of them, although I have no personal experience with godspeed I wouldn't go any cheaper than SPC, it's a safety issue to use cheap parts here, off my soapbox)...

Caster is the angle of the steering's pivot point from front to back of the car. It's kind of a pain to visualize but there are diagrams that will explain it better than I have been able to. Basically it will cause some tire lean while cornering and with too much caster may increase steering effort, but more caster will also add to higher speed stability. Long story short, it's not something to be worried about (unless you somehow ended up with less caster than OEM). The cross caster spec is really more important than either of the corners individually, but almost a full degree difference from side to side would probably have me going back in there to try to even them up. Keeping them even will also reduce the cross caster of course.

I'm guessing here, only because I've never experienced it being that far off side to side, that you will probably have a different steering sensation when turning (hard) right versus left. But it's not going to be a huge problem. Also on the vast majority of lowered Gs/Zs, the caster increases. It's just another angle change that becomes a variable in our suspension geometry when we mess with it.

 

He's right caster is not adjustable. It could, however be out of spec because of worn suspension parts. My compression rod bushings were shot and causing caster to be off. If the parts are good, however, there are a few camber kits that offer adjustable camber, but its really not that important. Otherwise, twisting the frame for perfect camber is an option and I've known shops to do it.