Spring Rates For Motorsport - What Do You Guys Have?

[OLLIE_NZ]

Hi fellas,

I know there's a tonne of threads about springs etc but I can't really find anything relevant to what rates the majority of people use for their circuit only cars.

As some of you know I have a 1994 R32 GTR which is used exclusively on the circuit.

-The car runs full slicks (240/640R17) Michelins/Dunlops

- Has fully adjustable Ikeya arms for full caster/camber/toe adjustment.

- We have a Cusco front sway bar but only a stock factory sway bar on the back (is this a bad idea?)

- Shocks at the moment are HKS Hypermax III

- Weighs close to stock (only the interior, sound deadening, air con, hi-cas removed)

- Is used on a pretty smooth track that is only a few years old. Has quite a few cambered corners and some elevation changes.

Please can you guys list what spring rates you use for the track and what you think would be the best for us.

We plan on buying Eibach springs as we have a dealer fairly close to us.

A friend runs 900 fronts and 650 rears (he would like to drop to 500) on his R32 GTR circuit car.

I'm happy to provide any more info if it helps.

Cheers.

[Duncan]

Wow, that many responses eh?

I am not surprised, a lot of people think they are racing for sheep stations and that they can't share the information they paid good (or bad) money for.

Having said that....I don't know mine Maybe Brad would be kind enough to look under my car and read the rates off the springs in a couple of spare minutes

[OLLIE_NZ]

Thanks for the reply Duncan.

I'm not sure why there's been no response so far.

I am hoping to go and buy the springs tomorrow and at this stage I'll be going for 900 fronts and 500 rears (unless someone here scares me off)

[Roy]

I would be guessing...i will say though that if you are running HKS Hypers they have pretty high rates to start with and not sure putting a different spring on them is really going to give a good result.

I would personally even out the swaybars with the same brand out back....and save your money for some better shocks which come with the valving to suit spring rates suitable for slicks.

[Risking]

Roy is on the money.

Duncan I'll have a look under your car tomorrow.

I know what rates alot of the local quick GTR's are running

(several of them have been over the last few months)

but each car is different, there is no one size fits all.

[UWAM]

How does the car handle at the moment? Does it feel soft/firm, slide lots or take a steady state corner set easy, good response or sloppy feel? How does it respond to whatever bumps/kerbs there are? What's the balance (over/understeer) like?

[OLLIE_NZ]

Hi guys, thanks for the replies, I've just woken up so will write a better reply soon to answer some questions.

I never mentioned what our spring rates were or the fact that they are progressive which isn't what we want I'm guessing?

Roy, I'll pop out this morning and grab a rear Cusco sway bar.

For the fact that the springs are progressive and that we don't mind coughing up for some replacement Eibach springs should we just do it, if so does anyone want to throw out some numbers?

This is what's written on our springs which for the life of us we couldn't work out what they meant.

Rear 'Merwede Progressive 250 49 98'

Front '25 250 59 118'

We then emailed Merwede to hopefully get some answers, this is the response email (I've tried to add the conversions in red)

Good morning,

I've looked for the springs in our system, but was unable to find it. But nevertheless, I think I know the spring rates from the code on the spring.

For the rear it's progressive from 49 to 98 N/mm (280lb – 560lb), (5kg/mm - 10kg/mm)

For the front it's more difficult because that code doesn't mean much to me. But if the spring is also progressive, it will be 59 to 118 N/mm (340lb – 675lb), (6.4kg/mm - 12kg/mm)

Hop this serves you well.

Best regards,

Ramon van Dijk

Merwede Springs

Edited January 8, 2012 by OLLIE_NZ