Nice video and cool track. Thanks for posting the alignment details - pretty similar to what I used on a 987S with Nt-01s. Running them at 36psi hot?

 

Why are you going to 1400/1500 over the current 1100/1200?

What type coil overs are you using?

 

34/35 hot

 

I am using JRZ PROs with remote canisters. The 1100/1200 rates are still a bit soft and we are having to run the compression fairly stiff to get the car dialed in. When we initially looked at rate selection for this application, it was calculated at 1484/1598. Based on my previous experience, I settled on 1100/1200 thinking the car would be overly stiff but I was wrong. The shocks I'm running are very good and make the 1100/1200 set up feel down right soft. I was actually shocked (no pun intended) how soft they made the suspension feel, softer than my previous 700/800 set up. Hard to believe, but comfort wise my current set up is better than either my old H&R coilovers or the RUF PSS9s I ran previously. The 1100/1200 rates are great for the street when the compression is dialed back but still a bit soft on the track. I realized it after two laps in the initial set up. We thus settled on 1400/1500 as a final spring rate so we could control pitch and roll a little better and at the same time dial back the compression down closer to the middle. If you have high quality race shocks, high spring rates are not a big deal. You have to remember these cars are relatively heavy at 3200-3400lbs on the average. 997Cups are 2700lbs and run 1450/1450 rates with RSRs even higher. A friend of mine rode in my car around town and commented how the car rode better at with 1100/1200 than his stock 997.1TT Damptronics. Good shocks are the key...

 

^^^ I figured in the past the same to run higher spring rates. The TTs are heavy cars (as you pointed out) and need a good platform to perform really well.

From my experience you need the difference between front and rear springs no more than 200 lbs else a lot of oversteer results.

Post the results of your new spring rates in the future.

I run the rear compression almost full stiff.

 

Thanks!

I've modded my subframes to Cup specs. All monoball bushings too. Weight's about the same, but spring rates about half...for starters.
Do you have spring specs at hand? ie manufacturer and lenghts?

 

Running NT-01s at 32-34F, 34-36R hot.

 

Current springs are Eibach ERS (first number is the length in inches, last number is the rate in lbs.)

Mains: 0500.225.1100 fronts (5") and 0600.225.1200 rears (6")
Tenders: 0175.225.150 fronts and 0175.225.250 rears

New main springs: 0500.225.1400 and 0600.225.1500.

I did over 170miles at the track yesterday and the 1100/1200 rates are definitely a touch soft. 1400/1500 should be just about right.

 

^^^Thanks again!

 

Love the pictures... drool.

 

Great info, thanks for sharing. ..one day..