I'm getting the Ground Control 2.5" coil-over setup with KYB AGX shocks/struts, and probably Eibach sway bars. My question is: what spring rates should I use? all I know is that stock is about 90lb/in, Eiback progressives max at 195lb/in, and the Tein coil-overs come with 4x0lb/in front and ~380lb/in rear. Ground control gives you a choice of which springs when you buy the setup; I"m just trying to decide when I get mine. I LOVE a stiff ride, and handling IS the most important reason for spending this money, so obviously the higher the rates, the stiffer the ride. I basically want to know how stiff is too stiff. I live in VA on some windy country roads, and not all of them are in perfect shape, but most of my driving is done on decent roads. I was thinking of 500lb/in all the way around, but get the impression that might be a little stiff. I'm also going to replace a few bushings and get caster/camber plates and rear-camber adjustment link.


Merry Christmas to all!

Stephen

 

i have the K2rd set up and on some bumpy roads it's waaayy over kill. It's only like 350 and 300, can't remember which is which. But 500 is WAY too much. Unless you don't like your teeth fillings in their place.

 

Thanks for the info. What kind of shocks are you using?

 

When you order your coilover setup from GC ask for Tony. He is their RX-7 expert. If you ask him what spring rates you should buy he will probably ask you what shocks you have and what kind of racing you do.

They originally sold me 300lb front and 225lb rear springs for my car. And against their recomendations I went up to around 400lb in the front and around 300lb in the rear (with no rear sway bar).

I too use the KYB AGX shocks and for racing they are garbage. I suggest you get some spring rates around what they originally sold me (300/225) because the higher in spring rates you go the worst the shocks will react.

To run 500lb springs up front you will need some real shocks built for racing. The AGX shocks will not be able to dampen the bounce you get from that high of a spring rate.

And there is NO reason to go with 500lb springs in the rear. The car would have crazy oversteer with that stiff of a spring.

The ITS car I am building will probably have 450lb springs in the front and 325lb springs in the rear (no rear sway bar). And I will get a junkyard motor to run with if that is the only way I can afford to invest in some real shocks like the Advanced Designs or Koni racing shocks.

 

yeah, I talked to Tony at GC. He told me the AGX shocks were good for the money. I can get Tokico Illumina's for ~$105 each, which is the price he quoted me for the AGX...which would be better? Thanks for your help!

Stephen

P.S. Do you know of any good books I can get about suspension tuning?