I am curious what spring rates people are using for tracking their F?

I have KW v3 coil overs and they are way too soft and I have been thinking about replacing the springs only with Swift springs.

So I am curious, if anyone has selected or can recommend a spring rate for our cars? The front especially as under heavy braking I can get the front to bottom out the body on the top of the tires. Not a great feeling when your going into Turn 5 at Canadian Tire Motorsports Park.

You can see how much the front is compressing here.

 

From my research, 9 kg/mm to 10 kg/mm on the front and 16 kg/mm for aftermarket springs should be sufficient for RCF transitions under high inertia situations. The Swift springs seem to have similar spring rates. It will also maintain decent Streetability. You don't want to go too stiff on the front as it will increase understeer.

​​​​​I never found stock spring rates, but it is around 8 km/mm front and around 14 kg/mm rear (TVD RCF have slightly stiffer rear spring rates than LSD to promote rotation and the added weight of the TVD unit) so Swift with a shorter compression stroke, is slightly stiffer than stock.

I am surprised the aftermarket KW coil overs have such soft springs as I would expect them to be more aggressively rated spring rates wise than stock.