slate blue

You have the wrong spring rates, I had my engineer work out appropriate rates given the vehicle weight balance and wheel motion ratio. If you are using 600# front springs you should use either a 250 or 225# rear spring. The weight of the rear of the car will be the difference, autos being a bit heavier at the rear and some cars are lightened also, that weight is usually removed from the rear. Also on track days the spares etc are removed. If you were using 500# front springs the spring rate would be around 175#. When you make changes you need to be careful.

UpFixenDerPorsche

Slate Blue,

Out of curiosity, what motion ratios did your engineer calculate for each end?

Cheers

UpFixen.

sny928

Hi Slate Blue. I appreciate your recomendation! As I planned to get the Hypercoil kit from 928motorsports (that's where the 600/400 numbers came from) I will mail them and ask if they can put together a 600/225 kit instead.

/Sverker

slate blue

From memory it was 0.5 for the front and 0.78 for the rear. His view was it was the 600/250 was way too soft for the track but this car is a street car. There is another car which has much stiffer springs.

UpFixenDerPorsche

Many thanks.

slate blue

Of course you need to know your vehicles weight and weight balance. So we put it on the scales and made an allowance for fuel. This is why I said to the original poster it depends on what car you have. You see my manual 928s versus say an automatic GTS will have a slightly different weight and balance.

What my engineer likes to do is have the car corner with equal lean, that is the car doesn't want to roll more at the front or rear relative to each other. The handling can then be fine tuned from there.