Originally Posted by M3SQRD
I'm surprised the DA damper can handle a F spring rate of only 450 lbf/in max! I was running their SA setup with 400/672 rates, and the SA damper/strut had no trouble handling a F rate of 400 - I thought the DA kit could handle a wider range of rates than the SA kit?
We have tried spring rates from 350 all the way up to 550 on the front of E9x non-M and M cars either for customers or during our Redline Time Attack days. 450F with the rebound damping cranked near all the way the front suspension is right near critical damping. The damper seems to be happiest with rates in the 350-450 range, not higher.
Was the SA on an E9x M car? Do you think the vehicle was at critical damping or slightly under damped? On SA kits, I don't recommend anything over 400F.