EDC

I have a 1999 C5 with just the basic suspension. I want to upgrade the suspension for the track. And I want use it on the street. How about the T1 suspension package from GM? Any other ideas that would work?

EDC

John Shiels

I would do it but make sure you will like the ride. It will be extra stiff and you may tire of it. You could do T-1 bars and rebush your existing control arms. Basic to T-1 will be a big diference If you want I may be interested in the springs if you do not what them from the kit. How much experience do you have at the track? Seat timewill help more than thekit in the beginning. Tires are a first. Maybe a sway bar and tires would be better spent money.


[Modified by John Shiels, 9:21 PM 8/25/2002] :seeya


[Modified by John Shiels, 9:25 PM 8/25/2002]

tcmc5

My set-up on my '00 coupe is Hotchkis bars, Bilstein Sport shocks and Vette Brakes bushings. This combo works very well for the track and autox without being obnoxious on the street. The bushings are a pain to install but really tighten up the car. By the way I started with the Z51 and the above is a very big improvement for a lot less than the T-1 if you don't need an all-out track car.

gstama

I have a Z06 with the T1 sway bars, VBP 800 lb spring, Penske DA and Poly bushings, the car is just amazing at the track could not be happier, the sway bars so far make no noise as reported by others but i think that the heim joints over time might change that, there not intended for daily street use and will wear from what i have been told.

4stroke

I have an 01 Z06 with T1 bars on an otherwise stock suspension which I run at TWS . The bars significantly flaten the car in the corners and are tolerable on the street. Check the torque on the link nuts frequently as they tend to loosen up. I also agree that seat time is more cost effective than extensive investment in mechanicals if you are just getting started. Have fun.

VBP

If your starting out I would use the Xtreme #800lb. front spring, Polygraphite bushing kit, Bilstein sports, and an alignment. That will get you a good baseline until you get more seat-time. You could also go with heim end-links and heavy-duty toe-rods if you were doing high-speed events. :flag

davidfarmer

I agree with VBP. Unless you are required to run T1 springs (as SCCA racers are), go with VBP springs. They are easier to install and offer much more ride height/corner weight adjustment.

Dave

Dreamin

What is the spec (lbs.) for the T1 springs?

rbeckham

I'd like to know, too, but it seems to be top secret, at least at GM. You'd think that somebody (VBP?) would have tested them, but I asked some time ago and was told they don't know!

VBP

How long ago did you ask and who did you talk to? Things change around here everyday! Anyway, the stock T-1 rates are 650lb. in front and 800lb. rear. We don't like to go that high in the rear unless you have an aero kit. :cheers:

Bill Benavitz

vbp, so, your front sport spring is 800lbs, the T1 is 650lbs, and the stock Z51/ZO6 is 580lbs. Is this correct? If I get your front sport spring and leave everything else (in my sig) the same, won't I now have a fair amount of understeer on the track (sebring, moroso, homestead)? Can I run this on the street without pounding my fillings out?

VBP

Yes, our spring design is totally different than stock GM so the rate's change as well. Your car will handle very well with what you have with the #800 front spring and without knocking out the fillings. ;)

rjn

VBP,

Can you provide a little more insight on this? If I increase my front spring rate by over 33%, all other things being equal, conventional wisdom says I've got a car that won't turn. What am I missing?

Thanks fo any insight,
Rob

ifeeltheneedforspeed

rjn, what I think he is saying is that the spring rates listed by various manufacturers are not measured the same way. Also the spring designs are different enough to make direct comparisons difficult. I am going to give the front sport spring a try. Its $539 plus shipping. Not bad for what may be a significant performance increase at the track. Right now, my car has a fair amount of front end dive which tends to unsettle the car and make the rear end too light at the turn in on the tracks (sebring, moroso, homestead). I also think the front end dive causes to much weight shift and hurts the braking performance.

VBP

The higher rate front spring will increase the roll stiffness and decrease the nose-dive. The nose-dive is the most important problem, especially on a C-5. Under hard braking all the weight transfers to the front wheels which is good for initial turn-in but not good for middle-out. Also the C-5 has A.B.S. which has wheel speed sensors for the A.B.S. to determine how much brake to give to each wheel. If the weight is transferred to the front wheels the rear has less friction to the ground for braking which will make the A.B.S. system not give more brake to the rear. When you increase the roll-stiffness your getting more stability in the corners. You can also adjust the alignment according to your individual set-up.

gstama

On my Z i had the VBP front spring 800lb poly bushings and everything else stock except the alignment and the car did not have any push problem, no real difference from stock as far as push goes.
I thought that the stock Z spring was 680lb.
:chevy

rjn

VBP - Wow, nice summary..that's dead on! Thanks for the reply

Gstama - how do you like the polybushings for street duty & NVH? Once installed, will I be able to sell this to a non enthusiast a few years down the road?

VBP

Three reasons why our springs rate different than GM. First one is the composite matrix, we have more fibers per inch. Second is that we use less arch, not pre-loading the spring as much takes away the harshness. Third our rate machine is set up different than GM or TRW, where we have the pick-up points to test the rate. As you see it is very difficult to compare equally. :D

EDC

Wow,
What a lot of information. And what a delima. How about one more wrench in the works? DRM proposes independent suspension. Remove the Spring and use coil over shocks.

What I am looking towards, is changing my suspension for better track handling and not going back to redo what I have done. I know the C5 is good stock. But I want better. Later I will improve the engine.

Thanks for the great feedback,
EDC

jeanlucpicard

I have a 2001 convertible "WARP 10" and am wanting to clear my head a bit before ordering the VBP front spring. I drive my car daily (it's more fun that way) and I autocross. This is my 3rd vette - 1993 40th vert & a 1989 coupe before - so I'm not totally newbie at autocross and I do ALL of my own mods.

I have the F45 suspension package and I am concerned about the shock respond time to a stiffer spring. I agree with VBP that an 800# front mono spring would be a good matchup but I would like to deal with the reponse issue - it's not like I can just install a different set of Bilsteins. Would I need to set the F45 select switch to Performance mode always so the shocks will respond with the new spring?

Also, I'm considering the T1 sway bars - front and rear - with the Heim aluminum end links to compliment the suspension and reduce body roll. The F45 is only a base suspension with ride control (shock dampening).

Appreciate any advice here folks.

Save The Wave :seeya :cheers: :cool: