Calling All Track Rats

[Raucky2000]

What kind of spring rates are you running or recommend for a e90m? I'm going with TC Kline DA setup with hats and was looking for input on rates. I'll track some but mainly auto-x so I don't want much body roll at all. I will also drive some on the streets too, so it's not a track only car.

[Car54]

Call TCKline, they know what they're doing enough to design spring rates for you.

[M3SQRD]

Agree with Car54...contact TCK, BimmerWorld or VAC. Discuss your suspension goals as well as other mods (e.g., tires, rim widths, etc) with them and they'll give you spring rate suggestions/options.

[HP Autowerks]

Originally Posted by Raucky2000

What kind of spring rates are you running or recommend for a e90m? I'm going with TC Kline DA setup with hats and was looking for input on rates. I'll track some but mainly auto-x so I don't want much body roll at all. I will also drive some on the streets too, so it's not a track only car.

Front can range from 350 to 450, with 450 is the absolute max for TCKR front DA's. We have done more installs than any other TCKR dealer and have competed in Redline Time Attack in our own 335i and sponsored the only podium finish E9x M3 in stock RWD class. Anything above 450 you will likely to fun the rebound setting maxed out or require revalving. Rear can be 600 to 800, with 800 being max.

The best street and light track combo would be 350 or 400 front with 650-700 rear.

See an extensive review on one of many TCKR DA's we helped set-up here:

http://www.m3post.com/forums/showthr...light=tc+kline

[M3SQRD]

Originally Posted by HP Autowerks

Front can range from 350 to 450, with 450 is the absolute max for TCKR front DA's. We have done more installs than any other TCKR dealer and have competed in Redline Time Attack in our own 335i and sponsored the only podium finish E9x M3 in stock RWD class. Anything above 450 you will likely to fun the rebound setting maxed out or require revalving. Rear can be 600 to 800, with 800 being max.

The best street and light track combo would be 350 or 400 front with 650-700 rear.

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?

[HP Autowerks]

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.

[M3SQRD]

Originally Posted by HP Autowerks

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.

Yes, it was installed on an e92 M3. I played around with damping within a range of 0.5 to 1.5 turns from max (total range is 2.5 turns). The car felt well controlled at 0.5 turns (rear dampers were set between 0.5-0.75 turns) with 400/672 rates but my wife found the car to be "harsh" on expansion joints and bumps. At 1.5 turns the car obviously wasn't as well controlled but I certainly would not say it was underdamped; however, it made the wife happy! Just to be clear all of this was street driving, no track time.