OK, I installed RDR camber plates about a month ago and I am thrilled the way it handles and grips now. However, I noticed that my rear end will break loose at slightly higher speed that I was doing before in the canyon roads and even though it is kind of controllable, I would like to get more grip in the rear. my current settings are

camber front -2.2 rear -1.8. slight toe out in the front, stock toe in the rear.
h-sport sway soft in the front, stiffest in the rear. stock shocks. Falken st115 17s

What am I doing wrong?

 

these should reduce oversteer:

reduce stiffness for the rear sway setting
set front toe to 0.0

 

Yes, And what are your air pressures? Reduce front pressure and increase rear pressures if there is a big difference between the two when autocrossing.

Your alignment setting front and rear are too close.
I have Front -2.2 degrees camber, toe out 1/16" and rear -1.2 degrees camber and toe in 1/16" and this works fine for me on the street, autocross and track with 17x7 street tires or 15" competition tires and madness rear sway bar set to stiff (stock front swaybar).

If you still have oversteer with adjustments to the rear bar and with alignment then consider changing the front swaybar back to stock.

 

I would also swap out the ST115's for some GS-D3's or S03's.

ST115's are great for touring around town, but canyon carving is probably
really pushing the adhesion limit.

 

i also second this rear sway bar stiffness setting to be softened. With your mods, this would be the first change you should go for. Tire pressures make differences, but with an aftermarket sway bar, definitely make it a priority to take a look at that first.

 

I would personally keep tire pressure the same front and rear. You should capitalize on the absolute best performance from all four tires and playing with tire pressure front to rear is old hat. The balance you seek should come from a proper suspension set-up. It is hard to tell - without driving your car - when it breaks loose in the rear and how controllable the break is. If the the loss of rear traction is initiated by lifting off the throttle, this may be a good thing; if you keep your foot in the throttle and the car remains stable, I would say you've got a pretty controllable set-up. The holy set-up is controllable slow speed oversteer and high speed understeer - to a point. Also, if you reduce rear camber as was suggested above, the back end will become a little more loose - all else equal. I like a 1/16 toe out in front and 1/16 toe in in the rear. You can keep camber differential front to rear within .5 to 1.0 degrees - for example 1.5 degrees neg front and 1 degree neg rear or 2 degrees neg front and 1 degree neg rear. Whatever you do with camber, do it in the front first and then adjust the rear to suit your driving style. But, I'm going to focus on your sway bars. Remember that a sway bar works by transfering load as a car leans. Softer springs allow large sway bars to act more quickly than stiffer springs especially if if the stock springs are mated to lets say a 25 mm rear bar. Sway bars must be selected based upon the stiffness of springs and damping rates, and also, other desirable handling qualities. You might notice that some sway bar manufacturers rec. smaller bars for softer springs and heavier bars for stiffer springs. You should first determine the spring rates front and rear that you can tolerate for your driving conditions, then select a damper that is capable of controling the springs. THEN, select a pair of sway bars to fine tune the set-up. If you follow this path you will be setting up your car from the correct perspective - macro to micro, gross tuning to fine tuning. Your tire pressure should be 35psi cold for normal to aggressive street driving and perhaps 40 psi for autocrossing as a general guide.

Also keep in mind that making changes to your suspension is a bit like pulling thread in a plaid shirt...one change affects something here which in turn affects something there. Work systematically as I suggested above and you will reduce you headaches. Keep a log of all your changes too, so you don't get too lost when things don't work out. Sometimes, we have to start over, I know I have. Good luck.

Michael