I installed the coil overs in the back of my 88 GT with KYBs. On my stock GT, I went with the 350lb springs per the recommendation of WCF. The car drove fine with the stock struts, but now bounces too much. It took me a little while to figure out that I have either two blown struts or I have springs stiffer than the KYBs can handle. My gut is on overloading the struts. When I go over a bump now, the car bounces to much. It really feels like the struts are blown. I know that the stock springs are between 100-140lbs/in and that 350lb/in is too much. Does anyone know how stiff you can run the KYBs before they get over loaded? (And yes, I should have listened to everyone and gotten Konis)

KYB GR2?
I never had a problem with KYB GR2 and 350# rear springs.
Even with 450# front springs in the front, the KYB Gas-A-Justs worked great.
I was even was considering going to a stiffer front spring.

But if all you do is drive on the street 350 might be a bit stiff.
You'd have a harsher ride. I never felt bouncey with mine. Harsh? Yes. But I like it.

What brand are the springs?

Were you careful not to heat up the shock when you ground off the perches?

When I finally get my coil-overs done for my 1988 I plan to use these:

http://www.pitstopusa.com/detail.aspx?ID=3484

I couldn't handle 300 or 350 lb/in on the street.

it is probably the struts. they are not blown but the kybs are bouncy struts. hints the nickname Keep You Bouncing

I have the KYB GR2s from the Fiero Store. With the stock springs the car did not bounce at all. I will see if I can get ahold of some softer coil over springs and test them out. I know that the right thing to do is to save up and get some Koni's.

Do you have 8", 10", or 12" springs? The longer springs yield better performance.

I have the KYB and WCF 350# 8" springs in the rear. Have never really noticed any bounce. I used to get the bounce in the front back when I was using the ST springs. Went up to a 400# front spring and the bounce went away.

I don't really care for the GR2 rear struts either. They've always seemed a bit soft to me. But I love the gas-a-just front shocks. They are great for my street use. The roads are decent here so the higher spring rates work well in my case.

If I were to order new springs I would probably order QA1's from summitracing.com. They make a great spring for coilovers. Just wish they had something for the front...

[This message has been edited by Fieroseverywhere (edited 07-30-2010).]

quote Originally posted by Brastic: I know that the stock springs are between 100-140lbs/in and that 350lb/in is too much. Does anyone know how stiff you can run the KYBs before they get over loaded?

FYI, the stock rear springs were rated around 200-230 lb/in, depending on year and sub-model. You mentioned that your stock struts seemed better than the KYB's? This raises a red flag. Because the KYB struts are stiffer than stock. They should be less bouncy, but will probably be more jouncy (instead of the car body bouncing up & down relative to the wheels, the entire car gets jounced, because the suspension is so stiff).