S2 spring rates/lengths

[craig hughes]

Anyone out there know what the front and rear spring rates and lengths are for my '89 S2? Im replacing the shocks but the springs are shot too. I want the original spec so I can get AVO to supply a slightlty stiffer version of each.
Cheers,
Craig

[NicBowman]

Hi, don't actually know, but can tell you something useful ish I hope. I used to measure mine for sprinting (I had alot) by standing the spring on the floor, putting a plank on top then standing on the plank (lifting myself and steadying on the roof rafters in the garage). The kids then measured the height after compression, and before compression is easy. The rate is then your weight (in lbs +plank) divided by the compression in inches. Actually suprisingly accurate. The old springs should not be so knackered that the rate has changed, so should measure the same. If you are getting new stiffer ones, remember that the load on the springs when stationary is just the weight of the car, and you don't want the ride height to change. So if you have the same spring mounting and a stiffer spring, the stiffer spring must be shorter. Ideally get adjustable seat Avo's. I would not stiffen much, as it will soon get uncomfortable to drive in. Have fun

Nic

[craig hughes]

Thanks for that, i have used a similar trick in the past too. Im also a sprint and hillclimber, but not with my TVR, and was shocked at the wallowy handling! I have always used AVOs on my racers as the guys and girls there are dead helpful, hence my choice of adj. seat versions. It may just be the shocks, but not convinced.

[mickypee]

I have 4 brand new springs in the workshop,I'll measure them for you and post the reply.

The fronts are standard S and the rears are slightly stiffer V8S but they are the same length.

[19560]

I think that Joospeed is running 400lbs/in at the front and 300lbs at the rear. May be worth running with 2/3 of those values. Have you read www.pistonheads.com/gassing/topic.asp?p=1&f=6&t=104109&h=0 ? The Cerb weighs 1100 plus a little kg IIRC

[19560]

How did you get on Craig?

[craig hughes]

from what i can ascertain, the springs are relatively soft on the rear from the factory, so suspect that just changing the shocks will do the trick.
Thanks for the help,
Craig

[joospeed]

19560 said:

I think that Joospeed is running 400lbs/in at the front and 300lbs at the rear. May be worth running with 2/3 of those values. Have you read www.pistonheads.com/gassing/topic.asp?p=1&f=6&t=104109&h=0 ? The Cerb weighs 1100 plus a little kg IIRC

I'm actually running 650 front and 450 rear, peter H runs close to that but not quite as stiff ..
I woud suggest 350 front 300 rear would be resonable compromise.

www.joospeed.net

[shpub]

19560 said:

I think that Joospeed is running 400lbs/in at the front and 300lbs at the rear. May be worth running with 2/3 of those values. The Cerb weighs 1100 plus a little kg IIRC

The Cerb is a lot heavier than that in reality. Closer to 1200-1300 kg depending on when it was made.

A V6 S is around the 950 mark and a V8 version is around 1050. Agree with the rough rule of thumb. However when running stiffer springs, usually necessary to reduce the spring length so that the ride height is correct. Yes you can drop the platform but often that leads to the spring unloading or bump stop problems. Worth sitting down and doing some sums...

[pies]

joospeed said:

[ I'm actually running 650 front and 450 rear, www.joospeed.net

Do they actually compress

[joospeed]

pies said:

joospeed said: [ I'm actually running 650 front and 450 rear, <a href="http://www.joospeed.net">www.joospeed.net</a> Do they actually compress

no

[19560]

joospeed said:

I'm actually running 650 front and 450 rear, peter H runs close to that but not quite as stiff .. I woud suggest 350 front 300 rear would be resonable compromise.

Thanks shpub and joospeed. So I was a little short of the cerb weight and well short of js spring rate. One thing puzzles me though - for a 350 front end wouldn't 250 at the rear be a better balance?

IMHO costing at least three times the price of springs makes dampers are an expensive bodge esp. as you need to remove the springs to change them, unless you need new dampers anyway but even then it's surely a false economy and an inferior set up.

[GreenV8S]

19560 said:

One thing puzzles me though - for a 350 front end wouldn't 250 at the rear be a better balance?

You need to factor in the effect of the front antiroll bar, which is more significant with softer springs. I expect you'll have the thicker (1") bar. I haven't measured these but did calculate the rate at one point, they're surprisingly stiff. But if you have the standard rubber drop links they drop the effective rate significantly. That's the problem with suspension setup questions, in order to find a proper answer you need to consider the vehicle as a whole, including the driver. And there are always factors you didn't think of!

[joospeed]

19560 said:

joospeed said: I'm actually running 650 front and 450 rear, peter H runs close to that but not quite as stiff .. I woud suggest 350 front 300 rear would be resonable compromise. Thanks shpub and joospeed. So I was a little short of the cerb weight and well short of js spring rate. One thing puzzles me though - for a 350 front end wouldn't 250 at the rear be a better balance? .

It might be, then again it might not .. personal preferance .. you wouldn't know until yuo tried it out ..
But the original post at the top is for an S2, with a 2.9 and limited torque, so if you wanted tail out fun you could do with a slight raise of read wheel rate compared to a fire breathing V8 of course .. but then again - you wouldn't know until you tried it ..