tb30570

I ran my new suspension setup this weekend at autox. My Z51 C5 has C6 GS sway bars (31.0mm-front/27.9mm-rear) and G6 GS shocks. By the end of the slalom, the car had way more body roll than I expected.

What should I try next?

VGLNTE1

Get rid of those sloppy stock shocks and get coil overs.

tb30570

any coil-over recommendations with budget in mind?

do you think running coil-overs in the front and upgrading to Z06 rear leaf springs but leaving the C6 Grand Sport shocks would work?

tb30570

here are some parts and info:

Coilovers
http://www.c5racer.com/catalog/corve...1997-2012.html
http://www.c5racer.com/catalog/corve...ette-0197.html
http://dougrippie.com/?p=439

Shocks Only
T1-12480094/12480095
Bilstein Sport
http://www.westcoastcorvette.com/p-3...2013-c5c6.aspx

Springs
Base-440/577
FE3/Z51-525/634-22178729/22171757
FE4/Z06-525/714-22178729/22188038
T1-582/793-12480063/12480064
Hyperco-625/850
VBP-600-1225/625-900
http://www.corvetterecycling.com/product_p/22188038.htm
http://www.southerncarparts.com/corv...ngs-p-390.html
http://www.vbandp.com/C5-Corvettes/S...0&limit=100000

JiminVirginia

The cheaper way to go is, first, to install a stiffer front bar, like a Pfadt Heavy Rate adjustable. See how the car handles. It will be a lot better in transitions.

Then see if you still need springs or a coilover setup.

Jim

tb30570

That bar is about $1100 while a front 12480065 T1 bar is about $240. Obviously the T1 bar wouldn't be adjustable. If you think I need more bar rather than more spring, do you think this would be an effective option?

tb30570

does anybody know the dampening force differences between a base C5, Z51 C5, Z06 C5, T1 C5, base C6, GS C6, Z06 C6 and Z51 C6?

Tormania

I was gonna say I have a 2000 C5 with 123K miles on it, Z51 equipped. Put Bilstein Sports on it years ago as well as lowering it about 1" on the factory bolts and the body roll isn't too noticable, although it was not tracked in stock configuration for me to do a side-by-side comparison.

el es tu

You have a more oversteer oriented suspension setup right now (relatively speaking). stiffening the front wouldnt be a bad idea to rebalance the car a bit along with reducing some of that body roll.

Heres a chart comparing c5/c6 sway bars:


chart for spring rates and bar diameters:


C6 GS which is unlisted uses C6 z51 front and rear springs, Z06/z51/gs 31mm front bar, Z06/gs 27.9mm rear bar, z06/gs front shocks, and gs specific rears

hope this helps in making your decision!


EDIT:

Some shocks rates and an associated article:

http://www.pfadtracing.com/blog/?p=53

tb30570

how does this set-up sound?

Shocks - C6 GS in front and rear
Springs - C5 Z51 in front and 22188038 C5 Z06 in rear
Sway Bars - 12480065 C5 T1 in front and C6 GS in rear

Cost:
22188038 - $150
12480065 - $240
total - $390

I'd still have the option of installing coil overs or higher rate front leaf spring if there was too much oversteer or if the body roll didn't improve enough.

QA1 Precision Products GS402-09650 - $490
12480063 C5 T1 Front Spring - $790

63Corvette

I run my stock 04 Z06 on slicks (scrubs are cheaper than street tires) and don't notice any excessive body roll. If you "must" modify something in the suspension:
A) What are the requirements of the sanctioning organization which you must meet?
B) Why not use the tried and tested "GM T1" factory suspension?

Suspension setup is a package

trapp

I had the same car as you......added Bilstein shocks, T1 Sways, HPT hyperco Leaf Springs..........it turned out to be a wonderful combination.

el es tu

C6 Z06 front are the same as the GS front. The rears are different.

If I was in your position Id start with the t1 front bar or preferably both so youd have adjustment (the t1 front with the z06/gs rear may allow too much understeer for your driving style). Going stiffer on that rear spring may not be what you need just yet - also the stiffer the rear spring, the more you will have a tendency to get the rear end bounce over mid corner bumps. The bars may get you the roll resistance you need with the tires youve got. I think your shocks and springs are well matched so that is why Im not suggesting changing them out just yet.

What kind of tires are you running/plan to run?

JiminVirginia

The $1100 figure gets you both front and rear bars. They wil sell you just a front bar for half that. Just ask.

The T1 front is another way to go.

tb30570

the rear bar is already 27.9mm, so a T1 rear bar wouldn't be much different as far as I know.

shakedown067

What about just a nice set of double adjustable shocks as a solution instead of a whole new suspension setup?

tb30570

Ok, I'll start with a front T1 bar and see how that runs.

My current tires are street. They are Nitto NT05's all around (200 wear rating). 275/40-17's in the front and 295/35-18 in the rear. Wheels are 9.5" in the front and 10.5" in the rear.

I'm shopping for R compound. I'm already in SSM class, so switching to R compound doesn't move me to a different class as far as I'm aware. I'm looking at buying 17"x9.5" front and 17"x11" rear wheels. Smaller diameter rear wheels should drop the un-spring weight a little and keep the tires out of the fenders. If I get these, I'd mount the same size tires I'm currently running in the front (275/40-17) but run 315/35-17 in the rear. I'm looking at Hankook Ventus Z214 C71, Kumho Ecsta V700 Victoracer, Kumho Ecsta V710 or maybe a combination of those. My biggest concern about the wheel/tire combo is the OD ratio between rear and front. Stock rear tires have about a 4% larger OD than the front tires. This set-up about the same OD between front and rear which the antil-lock brake system might have problems with. The cost of this wheel/tire set-up starts at about $1510 and goes up from there depending on tire brands.

wishihad1-2

Do the Pfadt numbers include the roll resistance of the leaf spring? Remember that GM uses softer roll bars because the stock leaf springs provide a significant amount of roll resistance vs coil springs with the same ride rate. Thus if you switch to coil overs you almost certainly will want stiffer than factory roll bars since you have removed a significant part of the factory roll resistance.

BTW, based on Pfadt's marketing claims the factory roll bars would need to be VERY stiff since they have claimed the leaf spring's design works to promote, not stop roll (like a Z-bar vs an anti-roll bar).

tb30570

before I buy a T1 front bar, have anybody with the A&A kit installed one? It's pretty tight in there already with the C6 GS bar, so I just want to verify I'm not going to run into an interference.

(1) 12480065 T1 Front Sway Bar
(2) 12480068 T1 Front Anit-Roll Bar Insulator

$280.49 including shipping
http://www.superchevyperformance.com

$329.64 including shipping
http://www.gmpartsdirect.com

WICKEDFRC

Not to take away from the OP, but this will help contribute to the educational aspect of body roll.

One forum member set me a comprehensive list of things to check/inspect when it came to tightening up the suspension. It was much more than I could do a trial and error basis, but it was very clear what to try.....Hopefully, he will read this and add his list/link he sent.

Second, did you put this combination on your ride at the same time, or did you do it in increments?

I have T1s, QA1 Shocks, and stock springs but I am not completely satisfied with body roll reduction. From my understanding, it could be one of many or a combination of several issues. Worn bushings (124K miles), the weight of a C5 FRC vs a Z06, the additional weight of my 402 iron block over an aluminum block (especially on stock leaf springs, or even the shocks themself.)

What I do know is, the car pushes like crazy in turns. Understeer?

I am not convinced I need coilovers if I am not tracking the car, but I would like that stiff "handles like its on rails" non-exhistent body roll control when zig-zagging the ride.

What Blsteins did you use? Sport or HD?

What Hyperco Springs did you choose? They have Street or Track.