After my first track day with the TT I agree with Tom. Luckily my instructor used to own a TT so he had the same advice and it greatly helped. Coming from a Corvette this is a different animal. Its a blast to get out on the track and see what it can really do!

 

Here goes: You need stiffer springs regardless, as Al mentions a JIC would be a great place to start. However on low speed tracks like the one you describe (top speed of 122 mph) you still need to be running softer dampening rates if you want the car to turn at all. The car will lift the wheels regardless and the PSM will cut power. The only way to smooth it out with what you have now is to turn the PSM off. Stickier tires will only cause more G forces which equals more body roll, which means more lifting of wheels, spinning of tires and more PSM invasion due to body roll when your car understeers. Otherwise the PSM will never go off. On high speed tracks you can leave the PSM on, but on low speed tracks when you're softly sprung the PSM is far far too obtrusive. Has nothing to do with smoothness, the TT's suspension is way too soft for hard cornering with the weight. On higher speed tracks you are using more slow bump instead of fast so you can keep the inside wheels on the ground easier and PSM will be less intrusive.

In addition to suspension spring rates, a stiffer rear sway will help, you said the understeer scares you so that is a bit confusing. Do you prefer oversteer? If you feel safer with oversteer or a more neutral car a stiffer adjustable rear sway will help a lot. It will also prevent a lot of the rear body roll that is causing the rear tire to spin and PSM to kick in.

Al has 1300 lb springs and tons of DF with sticky tires so he never has to worry about much body roll and his tires stay planted, his PSM will not intrude as much, but if your suspension is less developed, there is no way around it all the movment under cornering upsets the car balance and trips the PSM. Your ride height is also much higher which means your center of gravity is too, which means more body roll and more lifting of the tires. PSS9's limit your ability to lower the car. Add camber plates and that will reduce understeer as well.



The progression should be:

1) Stiffer Rear Sway
2) Stiffer Springs/ Better track coilovers
2a) Camber plates/pillowballs


On a low speed circuit PSM is cutting your ability to get the car rotated because it's cutting power because the inside wheels are lifting and spinning. The car won't rotate without power, so you have two options, settle the car so the PSM wont interupt (meaning money in suspension mods) , or turn the PSM off. With your power levels the gyrations under cornering are much greater than stock so the affect is increased compared to a stock car with stock power levels.


Hope that helps explain better.

 

Jon,

That was an excellent post. Rep to you.