John Shiels

I guess I'll try it on the front and see how it handles but there is nothing like the track to test it. Anyone else running it?

LTC Z06

What is the stock spring rate for a coupe?

ghoffman

I had a VBP 650# on my 00 FRC, and it was great. The stock Z51/FRC spring was about 500-550 or so I have been told. Judging from the feel (admittley very very, inaccruate) that 500# number seems reasonable. The T1 springs are about 900# but the VBP spring is not as cambered as much as the Chevy spring which is a good thing so it has a greater height adjustment range.

John Shiels

Iwas told the Z51 was 700 lb. :confused:

tcmc5

I'm very interested in knowing how a much stiffer front spring will affect handling. Without a proportionate increase in rear spring rate won't there likely be a tendency toward understeer? I've been thinking about replacing both front and rear ( Z51 ) springs w/ VBP for frequent track use this year but would prefer to buy front only if it won't cause the car to push.

John Shiels

Gary what did you run on the back?

ghoffman

I ran the stock rear (Z51) with DA Koni's and Hotchkis bars. Since the front was only about 10% stiffer, a new rear was not needed. One might think it would push more but what really happens is that when you have it lowered with the stock springs and you are under braking your "real" spring rate is very high since the front end is bottomed out and sitting on the shock bumpers. With the stiffer spring you still have some travel and the turn in is very crisp. Even on the oval at NHIS the push was very moderate (I like the car a little tight).
For your 900# you probably want the T1 rear.
One additional trick is to tighten the bolts in the control arms so that the bushings are not being flexed at your standard ride height. Conversly, for LRP, you can set the bushing bolts so that one side is "staggered" versus the other so that you have it stiffer on the left side. Obviously this only works with stock type rubber bushings and not with a urethane or delrin bushing that is a real rotating bearing.


[Modified by ghoffman, 11:25 AM 1/9/2003]

Jim 47

Gary, I can't figure out what you mean by the above. What bolts are you referring to? All the bolts on my suspension are tightened to factory specs (which is very tight). If there's a way to tighten up the factory bushings, I'll sure give it a try. Thanks for your help. :cool:

ghoffman

What this means is WHEN you tighten the bolts. If you tighten them when the arm is at full droop, you add spring rate. If you tighten them when the arms are at normal ride height, there is no preload due to the bushing. It is a small effect but will at least make the bushing last longer

davidfarmer

I run their 900 in the front and 800 rear. My car is around 400lbs lighter than your (I would guess) which probably makes it act stiffer on my car, but I think you will like it. I imagine you will need a stiffer rear, however.

DAve

John Shiels

I'll know soon if I need a stiffer rear after I install it. The street is not really a good indication as I would never get going that fast on the street. Thanks for the tips guys. :chevy

DALE C

I have a 940 lb front with a zo6 rear spring (tested by VBP at 620 LBS) The set up seems to work good . It does seem to push a little on a hard corner entrance. I will probably up the rear spring rate at some point. I planned on going with a rear spring rate of 800-900 LBS but before I got a chance I broke my rear spring at Mid Ohio and put the Zo6 spring on. The car felt better than ever so I left it alone for now

John Shiels

VB recommended 700 for the rear for a match with the 900 lb. frt.

LTC Z06

Anyone know what the front rate is on a Z06?