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Composite Spring - To Buy or Not to Buy?



I have read all of the old threads on this topic, and it seems that there is roughly a 50/50 split on the composite vs steel springs debate. However, VB has their Composite springs on sale right now for $269 (down from $309). Granted not a huge savings, but hey 50 bucks is 50 bucks! What is the prevailing feeling on this? Should I buy it or hold off. My shocks are pretty weak (basically stock or stock like), so I need to do that too. Should I spring (sorry for the pun) for it?:confused
I've had a Vette Brakes composite rear spring on my C3 for about 15 years. Before that, I had two different steel springs--the first one, the OE GM unit, broke.

My experience with my own car and that with other C3s I've been around is the composite springs are more durable and they are a ton lighter.

The only problem with them is that because the composite unit is a single leaf and the steel springs are multi-leaf, when you switch, you loose the steel spring's damping due to the friction between the leaves. Consequently, a car that has been switched to a plastic rear spring but retains its rear shocks may seem underdamped at the rear. The solution is to go to a more aggressive shock at the rear in conjunction with the spring swap. Vette Brakes has a number of options for shocks, in fact, they used to strongly recommend use of Carrera adjustables at the rear when going to a composite spring. I don't know if VB still suggests that but the fact remains you need to do something with the shocks if you want the best handling. My own choice is Bilsteins with "Sport Valving". If you go with Bilsteins make sure you are getting "Sport Valving" and not the more common "HD" valving.
Exhaust heat is another issue here. Adequete shielding for the composite spring is required for longer life, as the spring is affected adversely by it. I was going to spend my money on some Thermo Tec, but got sidepipes instead, so I don't have to worry about this. I want to try a pair of Konis, when I need new shocks next time. --Bullitt

Hib is the expert and I can attest to his comments. I put a VB rear spring in my '81 at least 13 years ago. The ride improved dramatically with no loss in handling. I put in a set of Delco's also. Heat: I have 3" stainless pipes running back past the spring and have seen no noticeable heating marks. I highly recommend it, and ..... if I remember right, $269 is prety close to what I paid for it back then though it might have included the Delco's too. Still a nice deal.

........... Nut
I only mentioned heat, because the VB&P guys talk bout it affecting the warranty. I also have a composite spring in my garage that I will install this winter, because of the increase in performance and weight savings. I was surprised how heavy the stock spring was, especially when I conked myself in the head with it. :crazy Owww! --Bullitt
Thanks Guys, this has been really helpful. I think I will go ahead and get it. I plan to call them this afternoon and talk about shocks and such. Great info, exactly what I have come to expect out of everybody hear, even Nut!
I resemble that remark....

Jinx... You won't regret it.
"...even Nut." :s

........ Nut :grinsanta
OK, here's a twist for ya - they steered me away from buying it. The guy said wait till I could afford their fully adjustable one for $100 more. Go figure! What do you guys think? Should I hold out for the fully adjustible unit? I'm in no rush.

Sounds like a gadget you'll never use. Put $100 to use a lot better than an "adjustable" rear spring. Personally you could really have fun with the shock upgrade with another C-note available. I'd stay clear. Salesmen..........

....... Nut :grinsanta
Hey Nut

I read on some spec sheet that 81's were built with the composite spring. Is it possible that it was a mid-year change cause mine ain't got it do you know if yours did originaly? Could there have been a problem with the early versions and replaced with steel? I am curious about this and have seen no comments to suggest this.

In 81 only automatic cars had the composite spring, all 4 speeds came with the original steel leaf spring.

Not all 81 automatics came with composite spring!
I have an 81 auto with gymkyana suspension it
has the steel spring! Have heard the composite
springs are prone to splitting..... but given the
reduction in weight and better ride probably
worth putting on....... if your replacing shocks too!

Barry is right on. Gymkana Auto's did have the steel spring as did mine. But I love the composite spring now. The shocks are due for an upgrade this winter........... oow, back to the catalogs to update the Christmas list. :grinsanta

......... Nut
OK, ordered the spring this morning for $269. I got so much S___ comin through the mail for the '73 that my wife may make me sleep in it. How are they for that? I'm sure some of you have experience with this. Nut? :J

Get the dual mount version. I had the single mount version and sold it on e-bay.
On the lighest tension setting and the Bilsteins the rear with the VB&P recommended sway bar it never makes a misstep. The handling is unreal especially in combo with the front tranverse setup. I'm pulling over 1g according to the G-tech in a constant radias typical exit/entrance ramp.
So, you saw a major difference between the single mount and the dual mount. I know its adjustable, but I just did not see myself making a lot of changes to it. Is there really that much difference?
The big advantage I found was being able to lower the rear but keep the spring rate stiff.
My recollection was that all 80-82 base cars got the composite spring and anything with Gymkhana got the 7-leaf steel spring.

It is true that those early efforts at "plastic" springs were a little problematic. The durability of the C3 composite springs were not as good as the C4/5 springs nor as good as some of the aftermarket composites.
The 1981 was the first year to see the Reinforced plastic monoleaf rear spring. Other efforts to shed wieght were the use of thinner side class in the doors and roof panels, stainless steel exhaust manifold, aluminum intake manifold (continued from 1980) and magnesium rocker covers.

1981, 4-speed Corvettes and FE option came with steel rear spring, even some St. Louis built automatics made it out with a steel spring.

The 1980 were steel rear springs. The California Corvettes did come with the stainless steel exhaust mainfold and the Computer Command Control electronic emissions control system.

All 1981's had the CCC which provided fuel metering and governed the lockup of the automatic trans. torque converter clutch.
...sleep in it.


They all get over it eventually. Keep ordering. Remember, it's almost Christmas.

........... Nut :grinsanta

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