Rear spring lb rate

[sundance002]

Can anyone tell me what the rear spring rate Lb on the race car Cats?
I have a set of Avo 3 way adjustable shocks and find the 180lb rear springs to soft, I have just ordered 250lb springs for the rear matching the front.
Can anyone tell what they have used on there race car.
Thanks in advance

[sundance002]

DCL said:

Also interested in this - anyone got any info?

250 on the rear seems way too much to me, but would like to know what people use on track when they change from standard.

Edited by DCL on Thursday 5th May 10:52

At first I thought that, After speaking with Avo they told me the 3 way shocks I bought had 250 at the front and 180 at the rear.
My car pitches down at the rear, on acceleration and its only 70 more than I have. I run 300bhp and find I get awful wheel spin out of corners and I'm trying to cure it.

[sundance002]

k20erham said:

Hi Craig, you have the same engine as I do and yes the rear gets lively at best I'm running CR500's on 15x8" rims when hot(track) it was a handful when on the road(cold) it was scary but fun, in the end I went 3way Penske's and matched springs from Meteor and with the rear roll bar set fully soft it transformed the car and even in the wet became predictable, there is you tube footage of Danny Whinstanly ? at Oulton park doing a splendid job in his car who Simon did the suspension.
Simons advice is free and well founded.

T


Hi Ian, TBH We have got the power delivery really smooth, we set the VTec to come in around 4k. She is superb everywhere else, under breaking and turn in she is really smooth,The problem is, I have to stay off the power so long after apex that I loose chunks of time.
My rebound is set at 4 on the rear, dampers are matched to the spring rates,
I run on Avon Slicks Soft,
As you have no doubt found? Because of the large sump on the K20 we ran more ride height and had to allow for ground clearance, with the new design sump we made, it allowed us to set the ride height lower. This has improved the wheel spin slightly, As is suggested I will put the rear ARB on the softest, it now sits in the middle, Just getting frustrated.
On the bright side she didn't do to shabby last time out.

[sundance002]

Thanks all for your help, I will also speak with Simon.

[sundance002]

k20erham said:

Hi Craig,

Traction was a problem for me until Simon sorted things, Mine is dry sumped anyways lowest point being the bell housing/ dry sump joint, what LSD are you running and what final drive? I run 3.19 a Ford 909 7.5" motorsport diff so I never run out of gearing, on paper with the overdrive Sadev box that's 212 MPH at 8500 RPM!!

Think the LSD is a big part of the probest?
Have still got the original R500 LSD .
THanks for the tip, will look into the Ford Motorsport Diff. .