I have gc coilovers and kyb agx shocks. I was trying to figure out what spring rates I am using. I got this with my car used and I remember the previous owner telling me something about switching the spring F and R. I also just want to know for myself.

I looked on my springs and these are the Eiback and GC part #'s I got

Front: GC150.64.66 a 6" spring
or Eibach 112640

Rears GC200.64.44 8" spring
or Eibach 162856

I tried searching through the gc website springs, but I couldnot find matching part #'s. Any help would b great

 

GC150.64.66
150 = 150mm or ~6" spring length
64 = 64mm or ~ 2.5" I.D. spring diameter
66 = 6.6 kg-mm or ~369 lb-in (I think they just call it 375 or 400)

GC200.64.44
200 = 200mm or ~8" spring length
64 = 64mm or ~2.5" I.D. spring diameter
44 = 4.4 kg-mm or ~246 lb-in (they just call it 250)

To convert kg-mm to lb-in, just multiply by 55.88.
Easy.

BTW, those are standard rates that GC offers for the FC3S kit.


-Ted

 

nm beat me to it^^^

 

First number is freelength in mm, second number is I.D. in mm, third number is rate in hg/mm, so...

GC150.64.66 = 6" spring with 2.5" I.D. and 370lb/in rate
GC200.64.44 = 8" spring with 2.5" I.D. and 250lb/in rate

 

Cool, thanks guys.

My s4 t2 seems to understeer more than I like. I need new sway bar end links, the fronts are torn. I'm running gc coilovers, kyb agx, st sways f and r.

I remember my buddies s5 t2 drove real nice after I installed some real coilovers on his. I forgot what brand JIC or apex or something.;

 

I have the same springs and I have understeer also, even with -3 degrees of camber in the front and -2 in the rear. No uneven tire wear.

 

Everything was pretty much answered, but how does the car feel?

I decided to go against GC when getting my springs and went for more equal rates. I get a good amount of oversteer on the autox, but I kinda like it. A little too stiff for my tastes though. 380F/340R

 

With those spring rates and bars you should be getting a fairly neutral to oversteery car, unless you're running a stagger maybe? I've got ~400/275 with an RB front bar and a stock rear and it's pretty much neutral with equal tire sizes.

 

Yes my tire setup is staggered 235 45 17 fronts and 255 40 17 rears. I think also my st rear sway bar has to do with it too. Ive been trying to find my offset under my brake dust, but its really hard. I need to roll my fenders, it hits a lil under hard cornering. It also hits the inside frame tab that sticks out with spot welds, but that is another story


The guy I bought the car from actually said he reversed the springs at one point. I guess he put it back to GC specs

 

The sways *should* give you more oversteer/less understeer though, since the rear is proportionatly stiffer than the front compared to stock. If you've got the front bar on the hard setting, try switching it to the soft setting (the one closer to the end).

If it's the front that's rubbing, going to a 235/40/17 next time would help.