avizandum

Thinking of a ~ 650 lb. hyperco spring in front with a ~ 775 lb. Z06 spring in back on a Z51, These seem more along the factory "balance" of the OEM setup.

The questions are:

Does this make sense and/or has anyone done it?

Will the C6 Z06 spring fit on a standard C6?

(Car is an ASP AutoXer)

gkmccready

Can't answer your balance question, but for fitment all C5 & C6 front springs are interchangeable, and all C6 rear springs are interchangeable. How the rear springs are connected to the A-arms changed between the C5 and C6. As an example, the C6 Z51 front spring is actually a C5 Z06 front spring.

Most ASP cars I know of run huge VBP front springs and don't try to retain the stock configuration with a stiffer rear spring than front.

froggy47

My understanding also.

avizandum

Yep, standard ASP setup is 1000# front and 700# back. My car is still a daily driver and 1000# would be BRUTAL.

Trying to strike a compromise...

gkmccready

Well, part of that will be shock valving as much as the spring rate... but, yeah, that's a lot of spring.

FWIW:

C6 base springs: 420/620 -> Wheel rate: 127/99
C6 Z51 springs: 526/645 -> Wheel rate: 159/103
C6 Z06 springs: 531/782 -> Wheel rate: 160/125
Hyperco HPS: 565/765 -> Wheel rate: 170/122
C6 T1 springs: 582/850 -> Wheel rate: 176/136
Hyperco HPT: 625/850 -> Wheel rate: 189/136
VBP: 1000/700 -> Wheel rate: 302/112

Softest Coilovers I know of: 425/575 -> Wheel rate: 188/215
Stiffest Coilovers I know of: 800/750 -> Wheel rate: 353/280

And as a data point, I run 475/575 (210/215) coilovers on my C6 Z51... it's a lot stiffer sprung than stock, but it's fine for daily driving... for me. From looking at the data and knowing how popular the VBP set up is you may actually be better going HPT/base if you can do it without bottoming the rear shocks all the time...

jtmck

Try the 775lb Z06 spring in the back and leave the front alone.
Should give you the handling you want for autocross.

Jim M.

avizandum

Any more info / comments? Intuition tells me this will make the car tail happy. No?

My shock plan is Penskes SA valved for my setup with compression adjustability for the ride compliance.

el es tu

the car will get more tail happy from the standpoint of oversteer (it will be very controllable oversteer), but also due to the infamous rear end bouncing with rough sections. a z51 spring balance (which is more understeer oriented) will help eliminate that in the straights and turns. You can then use the sways to get the suspension dialed in to get the car to turn the way you want.



according to this chart:


Running the front T1 and rear z06 will give a balance similar to the z51.

Running a front Z06 and rear base (fe1) will also give a similar balance to z51.


gkmccready where did you get that data from? The chart I attached was found on this forum (and some parts vendors have posted this same one in the past as well) but Im not sure who originally came up with it.
I think Ive seen 3 different versions of the c6 spring rates. It would be nice for gm to post the values so thered be less confusion (i actually tried contacting several people including the manufacturer and couldnt get anything of use)...

acrace

avizandum - sent you an e-mail to your home e-mail account

gkmccready

Mine is pieced together from the forum, but largely the leaf data came from VBP and they measured a few stock springs on the same rig they use to measure theirs... the wheel rates are calculated based on measured motion ratios. I started a big thread a couple of years ago about that.

Cavi

What are the spring rates on the F55? Are they the same as base?

Cavi

also, anyone have a set of z51 springs for sale?

MisterMidlifeCrisis

Yes, F55 uses base springs, and you really only need a Z51 or Z06 front spring as the rears are basically identical already.

Werks

Would you happen to know what springs the ZR1 and Z06 with Mag Suspension uses?

MisterMidlifeCrisis

I'm pretty certain they use the same springs with any suspension.

Werks

Hmm interesting! Does anyone have any experience running stiffer springs with the magnetic suspension shocks in place?

Cavi

the f55 cannot be the same springs as the base, the reason I say this is on the build sheet there is a option for F55, and a oprion for FE1 or FE2 or 3, the FE1 is the base, soft handling, the fe2 is considered Handling and the FE3 is conidered sport, so it makes sense that the fE2 uses different springs

trackboss

1000lb front spring, IMO, would not be brutal at all. I run much more front in my C5 and the ride is firm, but not annoying at all. I'd say the rear spring contributes more to ride quality than the front. I have found that street tires are a bit over powered with a front spring well over 1000, but on the track I'd probably go even stiffer than I have if I could. I personally would consider anywhere from 900-1100 on the front for street tires. It would be best to use better suited dampers to improve ride quality and provide better control. IMO, the rebound in particular, needs to be a lot firmer than the stock dampers offer. Even with stock springs.

el es tu

fe1 and fe2 are most definitely the same springs and sways. email a vendor for the info.

the shocks are just different - stupid soft thin body shocks for fe1 vs mag shocks (fe2) with the ability to adjust to slightly stiffer on demand.

theyre definitely different than the regular z06 springs - diff part#s

*supposed to be softer.

Considering the sway rates on the zr1, and the way the suspension setups have been going with the c6 Id guess the balance would be more like the z51. That said its a guess - I emailed the manufacturer who told me gm could only answer the question (they dont give that info out), and then emailed gm but couldnt get any information either. Supposedly the parts dept of the dealership should have the information (according to my email response from gm)...

94boosted

Out of curiosity does anyone know what the C6 GS runs for springs? Is it a Z51 front and Z06 rear? Or are they unique springs?