Hey everyone. My S550 GT is setup on RideTech coilovers with Steeda front and rear sway bars. My spring rates are 350 lb front and 450 lb rear. The front sway bar is 35mm and the rear is 28.5mm. The front sway bar is a 4 hole adjustable and the rear is a 3. The front was originally set at the 2nd hole from stiffest with the rear in the middle. This setup seemed to work fairly well with the stock 19" Pirelli tires and wheels with the staggered sizing - albeit there was still understeer from the staggered setup when pushing it hard.
I have since moved to a 19x11 square setup with 305/30R19 R compound tires. I also installed Vorshlag caster/camber plates set at -2.6* camber with 0 toe. The rear is -2* camber with 1/8" to 3/16" total toe in. Brake pads are G-loc R16 fronts and R12 rears with brake cooling on the fronts. I had to move the front sway bar 1 hole softer due to clearance issues I'm having with the sway bar end links interfering with the bottom of the struts (another story).
Anyhow, I had some trips to Buttonwillow and a few other tracks with the previous setup. A couple weeks ago I got to run Buttonwillow with the new setup. My times improved considerably, but I now have some other issues to work out. The first seems to be spring rate related. I opted for 50 lb higher spring rates at all four corners than the default rates that RideTech selects for the S550 with the initial setup. The idea after talking with them was to find a decent compromise between street and track. This seemed to work well with the stock street tires.
Well, when I ran Buttonwillow last week with the new changes I was noticing much more roll when transitioning from one corner to the next, particularly in the higher speed corners. I believe this is from the extra grip and speed that the new setup is generating. For example, it was most noticeable when exiting Club Corner (high speed 45* right hand turn) and then immediately transitioning into the short left hand sweeper towards the Bus Stop. The car held it's line well without getting upset, but the body roll was significant (relatively speaking). I attached some great pics I got entering into and beginning the exit out of Club Corner. You can see how much travel the suspension is going through.
As a result, I'm thinking about upping the front spring rates to 400 lb fronts and 500 - 550 lb rears. I was hoping to get some input from you guys about this. The more I'm reading about suspension tuning for an IRS, the more I'm beginning to think that there needs to be more than a 100 lb difference in spring rate between the front and rear.
Also, in a somewhat related issue, I'm getting a low speed push when entering the tighter corners. I believe I can help the issue by introducing some trail braking into the corners. For suspension tuning, everything I've been reading says to soften the front sway bar adjustment. Is that correct? I'm also thinking of increasing negative front camber as well.
In higher speed sweepers I can induce some push with throttle, but it's nothing like the push in low speed corners. If I let off the throttle the front tends to bite more and the car feels neutral to a hair loose depending on how close to the edge of grip the tires are at.
Pics are below. Any input is appreciated!
I have since moved to a 19x11 square setup with 305/30R19 R compound tires. I also installed Vorshlag caster/camber plates set at -2.6* camber with 0 toe. The rear is -2* camber with 1/8" to 3/16" total toe in. Brake pads are G-loc R16 fronts and R12 rears with brake cooling on the fronts. I had to move the front sway bar 1 hole softer due to clearance issues I'm having with the sway bar end links interfering with the bottom of the struts (another story).
Anyhow, I had some trips to Buttonwillow and a few other tracks with the previous setup. A couple weeks ago I got to run Buttonwillow with the new setup. My times improved considerably, but I now have some other issues to work out. The first seems to be spring rate related. I opted for 50 lb higher spring rates at all four corners than the default rates that RideTech selects for the S550 with the initial setup. The idea after talking with them was to find a decent compromise between street and track. This seemed to work well with the stock street tires.
Well, when I ran Buttonwillow last week with the new changes I was noticing much more roll when transitioning from one corner to the next, particularly in the higher speed corners. I believe this is from the extra grip and speed that the new setup is generating. For example, it was most noticeable when exiting Club Corner (high speed 45* right hand turn) and then immediately transitioning into the short left hand sweeper towards the Bus Stop. The car held it's line well without getting upset, but the body roll was significant (relatively speaking). I attached some great pics I got entering into and beginning the exit out of Club Corner. You can see how much travel the suspension is going through.
As a result, I'm thinking about upping the front spring rates to 400 lb fronts and 500 - 550 lb rears. I was hoping to get some input from you guys about this. The more I'm reading about suspension tuning for an IRS, the more I'm beginning to think that there needs to be more than a 100 lb difference in spring rate between the front and rear.
Also, in a somewhat related issue, I'm getting a low speed push when entering the tighter corners. I believe I can help the issue by introducing some trail braking into the corners. For suspension tuning, everything I've been reading says to soften the front sway bar adjustment. Is that correct? I'm also thinking of increasing negative front camber as well.
In higher speed sweepers I can induce some push with throttle, but it's nothing like the push in low speed corners. If I let off the throttle the front tends to bite more and the car feels neutral to a hair loose depending on how close to the edge of grip the tires are at.
Pics are below. Any input is appreciated!