YELLOHHH

I'm hoping some of the road racers in here know. I'm not sure where to look this info up, so I'd thought I'd ask here. Need definitive info, not speculation. Thanks guys.

AU N EGL

Here is a start for you
http://www.jakelatham.com/c5/misc/faq.shtml#2-5

IM QUIKR

After calling LiteFlex, the manufacturer of the springs I found that Jake's page is inaccurate.
The Z51 front is 502lbs/in
the rear is 645lbs/in

the Z06 front is 526lbs/in
the rear is 714lbs/in

There will be some variation between years and A4 and M6,

ChasNMe

i was always told that one of the springs is the same. although i dont remember which one

TedDBere

The rear sway bars on the later Z51 and Z06 packages are the same (which is a spring BTW) but the Zo6 has stiffer transverse springs and a stiffer front sway bar.

apexman

Good info. I always thought the Zo6 rear leaf spring was the same as the Z51. Looks like I will be changing the rear up.

Derek

apexman

Not to hijack but does anyone know the spring rate for the front VBP xtreme?
I bought my FRC and it was already installed. Works great since I put the Koni SA's on with the Z06 front bar.

Thanks

Derek

John Shiels

They will make what ever you want. I have 1200/900 and 1000/800 FS

davidfarmer

really doesn't sound like anybody know, as spring rates are NOT measured in lb/in2, just lb/in

I don't remember the exact spring measurements (I did them myself), but the T1 springs are equivalent to coil-overs at 650 front/525 rears, approx. This is correcting the leaf to wheel rate, then converting back to the slanted shock mount.

TGrits10

Yeah I noticed that as well, I thought it might be a typo....however the rates seem too high regardless. ~500/700 would be remarkably stiff/uncomfortable for an OE street car, and much too stiff in the rear relative to the front.

That sounds a lot more like it, T1 is a track setup, so 650/525 isn't out of line...plus the f/r ratio makes sense.

For the record, if I had to take a wild guess, I'd guess the Z06 rates around 450/375....but that's based on how it feels relative to known rates on other cars, so I could be way off.

IM QUIKR

Ok sh*t for Brains, you're calling me a liar. The maker of the springs is LiteFlex , call them for yourself and ask for the engineering dept as I did and talk with John and/or Jeff for the actual spring rates. I wondered about the in2 as well but it seemed unimportant at the time because it went beyond my intial interest in knowing my spring rates. However, these numbers were the converted figures from Newtons or whatever force meassurement they are designed with. They were the rates that correlated with the embossed numbers on my springs and compared to the Z06 springs. But hey, why do anything more than GUESS, It makes you look like a genius.
I came with actual numbers from my discussion with the manufacturer just 2 days ago and you bring what to the table? Your best guess? Thanks for the input.

**There is a strong possiblity that the desired spring rate for a COIL spring would be different from the desired rate for a composite transverse leaf spring. So a "comparison" of actual numbers between the two might be bogus due to the non-linear loading with deflexion.

John Shiels

I sent them an email lets see if they answer it in writing to end years of debate.

Roadrace65

Before I started upping the spring rates under my 2000 FRC I had my stock springs measured by VBP - those numbers published by LiteFlex are very close to my actuals.

I'm running VBP 1050lb front 855lb rear and Love It!! She's Tite!!.....but not too.

TGrits10

Not calling anyone a liar; all I said was that the info LiteFlex gave you doesn't make sense from an engineering standpoint. I'm curious to see if JS can get a more detailed explanation from them to shed light on those numbers and help us understand them.

As far as my guess, I should have clarified that I was putting it in terms of equivalent coil spring acting at the shock mounts, as is the norm in other cars. However it's not bogus due to non-linear loading because the deflections are quite small.

John Shiels

Crazy part is I always heard the rears have a higher rate that the fronts in stock configuration. Then when anyone sets up a track car with coil overs or springs it is reversed with the higher rating on the front.

Roadrace65

From my notes - As tested by Vette Brakes and Products - 2000 Z51 Springs Front 503lb Rear 650lb

John Shiels

I ask VBP once and they said they didn't know which was unimaginable to me. Doubt I'll get an answer from LITE.

TGrits10

Hmmm what is it about the geometry that requires/allows such a stiff spring in the rear? IIRC the rear spring has roughly the same leverage on the A-arm as the front....dat's vierd....

IM QUIKR

John,

I had sent an email to Mr. Kovacs and he did not respond, I had to call and they were very nice folks to deal with. If you have some time, give them a call and explain that curious minds want to know and the results could be made public without attaching their name and website, so that they would not need to perpetually answer these calls. I would think they would be happy to help considering that the C5 is no longer being produced, the trade secret is longer a concern.

Good luck

IM QUIKR

The rear seems to have a longer lever from the fulcrum point.