Ground Control spring rates?

[Toadleg]

Long story short I drove in a pro3 e30 with GC with 640f and 800r spring rates. It was awesome felt geat. So I ordered a set up from GC, but they highly suggested I go with 500f and 700r rates. Anyone with experience that can tell me that should be fine?
current set up-
91 m50 swap full weight, h&R race srings, bilstein shocks, ST sways, New A arms, m3 offset bushings, Poly rear sub and diff bushings on order

[FunfGan]

I'm running 400/700 right now. Awesome, and perfectly dd-able but I want/ need something much more aggressive.

[HippyEarly]

in for replies

Im looking to get coiled, and as my sunday driver i don't need DD abilities, would prefer more action over 6 days a week doable.

[Toadleg]

in for replies

Im looking to get coiled, and as my sunday driver i don't need DD abilities, would prefer more action over 6 days a week doable.

Agree this does not need to be my daily driver. I told gc that I could trailer the car to the track but he still insist on the 500 700. The guy seems really cool and told me he would swap out the springs for free if they are too soft. Can't go wrong with that garentee but still want input

[einstein57]

I'd look in to a re-valve if you want to go higher then the rates they are suggesting. They just don't want you to put those higher rates on your car and say "these coilovers suck" when its really has to do with not properly pairing them to your shocks.

[Toadleg]

I'd look in to a re-valve if you want to go higher then the rates they are suggesting. They just don't want you to put those higher rates on your car and say "these coilovers suck" when its really has to do with not properly pairing them to your shocks.

The kit comes with the single adjustable shocks. Are you saying those shocks dont work with the higher spring rate so they dont want me to run that aggressive of a spring? If thats the case maybe im buying the wrong coilover kit

[einstein57]

The original post only mentions the bilsteins. You'd have to ask them what they revalved them to handle.

[E30_(1st Musk)_]

ive been in both an e30 with 500f/750r and one with 5**f/800r and i like both of them...some people will say that they are too stiff but it handles great when i was shotgun and im going that route even for my daily....but both of these cars had the short body koni's

[Chris916]

Last year i ran 550/750 gc's and it felt great. My car has an M50, fully gutted, 22/19 swaybars, about -3.5 degrees of camber in the front and roughly -3 in the rear, and was on 245/45 RA1's. The car was extremely neutral on track with 0 understeer and the perfect amount of oversteer. I feel like the rates could be a bit higher but i will not be changing untill i go with a more expensive coilover set up.

[Toadleg]

good info guys thanks. They are shortening my front housing also.

[Jean]

The kit comes with the single adjustable shocks. Are you saying those shocks dont work with the higher spring rate so they dont want me to run that aggressive of a spring? If thats the case maybe im buying the wrong coilover kit

Are you buying a FULL coilover kit or a $400 conversion and re-using your Bilstein Sports that you've listed.

Off the shelf shocks can only work so good, and thats what others mentioned... you either spring for a custom revalve job OR go with the recommended rates..

I am on 550/675 currently.

[robgoesvroom]

OP please answer what Jean is asking to better clarify. Are you planning on keeping the original Bilsteins sport dampers?

If so, I am currently on the GC coilover kit with 440# and 625# rates and my car is 60% daily driver and 40% trackday/autox car. Basically this is my only car (college student). The spring rates are okay for the track, more than comfortable as a daily driver, but I would like something stiffer. My rates were suggested by Jay from GC. If you have the money and you like to track your car, buy the full kit with adjustable dampers. Don't overlook proper valving and realize that the combination of spring+valving is key to a good setup, I learned the hard way.

as a sidenote, I don't know if you've been up to norcal and driven on highway 9. But the roads up there made me realize my setup is waaay to soft!

Goodluck, let us know what you end up doing.

[Toadleg]

Im ordering the full kit with them modifying the front shock housing. I told the guy if I need to I can trailer the car to the track I don't want to give up handling for comfort.

[Wanganstyle]

as a sidenote, I don't know if you've been up to norcal and driven on highway 9.
But the roads up there made me realize my setup is waaay to soft!

Yup. HWY 9 is the road of choice when bedding in brake pads, testing out tire pressures/spring rates pre-track day...

[z31maniac]

Another vote for 550/750, but I ran a 22 up front, with no rear bar.