Spring Rates for Track

[OutOn]

Do you guys think that 500 front - 600 rear could be a good start point for a coilover suspension for the Z4M Coupe which is mainly used for track days?

[OutOn]

Any inputs?

[The HACK]

Man...How to answer?

Spring rates are meaningless unless you know what other components are going to be upgraded and how much ultimately the car is going to weigh on those springs, especially if the car is going to be mainly used for track only.

So unless you can find out exactly what the final weight is, what is going to be removed, and what the final weight ratio is front to back, plus the tires you're going to run and their sidewall characteristics, your exact driving style, what sort of swaybars are expected...It's impossible to tell you if 500lbs/600lbs is going to work for you.

It'll be tantamount to my IT guy recommending a new PC for me sight unseen or figuring out exactly what it is I need a new PC for.

[OutOn]

Originally Posted by The HACK

Man...How to answer?

Spring rates are meaningless unless you know what other components are going to be upgraded and how much ultimately the car is going to weigh on those springs, especially if the car is going to be mainly used for track only.

So unless you can find out exactly what the final weight is, what is going to be removed, and what the final weight ratio is front to back, plus the tires you're going to run and their sidewall characteristics, your exact driving style, what sort of swaybars are expected...It's impossible to tell you if 500lbs/600lbs is going to work for you.

It'll be tantamount to my IT guy recommending a new PC for me sight unseen or figuring out exactly what it is I need a new PC for.

Sorry, you´re absolutely right.

The car is actually 100% stock with the exception of straight exhaust lines, Stoptech brake lines, Motul RBF fluid, PFC-01 front pads and CDV.

My idea so far is to keep on the standard sway bars. I´ll see if they are up to the job once I test the car with the coilovers.

I have a long experience with both racing cars, and road cars at track days. I´ve done 4 track days with the Z4M on standard suspension and recogn it´s time for a well stiffer suspension now. My guess is that 500-650 ´could´ be a good starting point, what do you think?

It´s not my daily car and I´m using it almost only for car meetings and track days.

Thanks a lot for your help. Your experience with the Z4M is a good bonus for me as well.:

[OutOn]

Forgot to add the main thing: I ALWAYS use slick racing tyres on the track. Dunlop Racing 245 front and 265 rear.

[OutOn]

And of course I shimmed the front suspension to get 3º negative camber front. I won´t shim it anymore since next time with the coilovers I will get camber/caster plates.