Spec Boxster Build

[thstone]

Going Square!

I had the opportunity on Saturday at Willow Springs raceway to drive my car with the standard staggered setup (Toyo RR's 235/45/17 front and 255/40/17 rear) back-to-back-to-back with a Brad Roberts car running the square setup (Toyo RR's 255/40/17 at all four corners).

The difference was eye-opening! When I got out of the car, Brad asked what I thought and I yelled, "I WANT THAT! I WANT MY CAR TO DRIVE JUST LIKE THAT!"

Once I calmed down, I explained that the square car had HUGE front grip on corner entry and had more grip mid-corner, with corner exit mostly unchanged. More grip will correlate directly to faster corner speeds and fast corner speeds typically translate to better lap times.

My stock staggered setup generally feels neutral at corner entry but corner speed was ultimately limited by mid-corner understeer; whereupon I'd mostly steer with the throttle (slightly less throttle to tighten the radius - more throttle to push it a little wider). If I would dial out the mid-corner understeer, I'd just get mid-corner oversteer.

The only downside to the square setup is that overall the car is a little more loose, meaning that oversteer happens more easily and quickly than with the staggered setup. I realized this after finding myself in a 120mph power slide though Turn 8 (where I had never had any oversteer before on the staggered setup). I admit, the few moments before I caught it certainly quickened my pulse rate!

My best estimate is that this could be worth 1.0-1.5 sec's at a track like Big Willow.

I sent the car to Brad today to make the necessary changes so I can run square at the next race in three weeks.