Competition Spring Rates

[petert 578]

A failed control arm bush led gave me the urge to revise front spring rates. Whilst they were out, I had them tested - 360lbs/in. However, they also had witness marks, revealing where they've been going solid regularly. I have another set of springs, which tested at 410. However, the suspension guru suggested that 410 wouldn't be enough if I'm currently spring binding at 360. So we've gone a huge step up to 515. This is to run with A050's. What's everyone else running?

[allanallen 528 2 Cars]

What spring length have you been using and how much droop/bump do you have?

What are the lengths of the 410s and 515s?

What rear bars are you using and what dampers?

 

It sounds like the current springs are too short. Do you like the current set up or do you feel it needs firmer springs?

Edited August 21, 2014 by allanallen

[petert 578]

I haven't got droop/bump measurements at hand, but it's way undersprung. The attached shot was taken when we had 23mm TB's. We've since moved on to Spax coilovers. Front springs: 410lbs FL 175mm, 515lbs FL 150mm.

[JeffR 51]

Interesting that you mention spring bind. On my 405 I've got the drivers side (engine side) spring platform wound up about 20mm higher than the passenger side to get the ride height same on each side. It seemed odd on one hand, but since the engine is on that side of the car I thought it made sense.

However I've noticed that there are witness marks from coil binding on that spring. Springs are 65mm x 7" x 400lb. Passenger side is OK.

I might have to get Aldo to make me another set of higher poundage ones too.

[petert 578]

Another on a faster corner.

Edited August 21, 2014 by petert

[allanallen 528 2 Cars]

Coilovers on the rear then? What's the wheel rate?

[allanallen 528 2 Cars]

Interesting that you mention spring bind. On my 405 I've got the drivers side (engine side) spring platform wound up about 20mm higher than the passenger side to get the ride height same on each side. It seemed odd on one hand, but since the engine is on that side of the car I thought it made sense.

However I've noticed that there are witness marks from coil binding on that spring. Springs are 65mm x 7" x 400lb. Passenger side is OK.

I might have to get Aldo to make me another set of higher poundage ones too.

20mm seems a lot?! Are they defo a matched pair?

[JeffR 51]

Good question! I don't have anything to test them with, but they were custom made and I assume they're matched. I'll get the next set checked before installing them.

Has anyone else found they need unequal spring platforms to get equal ride height side to side (16V alloy engine)?

[petert 578]

Coilovers on the rear then? What's the wheel rate?

450lbs, but who knows, I may have to up that now.

 

Jeff, you'll definitely need bigger springs. Contact Greg Nolan at Suspension Concepts. They weren't a lot more expensive than the other place. He's also happy to swap until you've got it right. He has a huge range.

[JeffR 51]

Thanks Peter, I'll give him a call.

[allanallen 528 2 Cars]

If that's a rear wheel rate of 450 that's very stiff, much higher than 25mm bars afaik. I'd certainly give the 515s a go. I've never gone coil bound on 500lbx150mm long springs with my iron block 309

[petert 578]

What do you think is the wheel rate for a std GTi torsion bar?

[welshpug 1,646]

circa 100 lb

[petert 578]

Seems low. I thought they'd be more like 150ish.

[allanallen 528 2 Cars]

There's a table in here

 

http://forum.205gtidrivers.com/index.php?showtopic=115888&page=1

 

Not guaranteeing it's accuracy but it's pretty close afaik