Don't drive with your nannies on!
With active handling in competitive driving mode, yaw control is still active and using the rear brakes to correct excessive yaw on corner entry/exit.
This causes the rear brakes to run hot, and in my case one of the rotors cracked as it cooled down in the pit. I even heard the *PING* as it happened.
To prove the point, I drove a session with TC and AH disabled, and spun the car exiting a corner. Coming from a Lotus Elise I've developed a habit of mashing the throttle on corner exit, as there never is too much throttle with an 1800 cc mid-engined car.
305 to 330 mm brake rotor
After some research online, I found that the C6 with the Z51 option code uses a larger 330 mm brake rotor, but still share the same caliper and parking brake dimensions.
- Increased thermal capacity. The EBC Z51 rotors are ventilated on both sides, have a higher mass and increase the swept diameter of the brake pad
- Better looks, the brakes fill the 18" wheel and looks more in balance with the front big brake kit.
- Reuse of stock brake calipers and parking brakes
- Change of brake brake bias. The increased rotor diameter causes a braking torque increase of ~ 10%, which could affect the front to rear brake bias. The C6 Z51 caliper has a smaller diameter brake piston to compensate, but I'm expecting the marginal brake torque increase to be within the capabilities of the ABS system, preventing early rear brake lockup.
- Increased unsprung mass, from ~6.5 kg to ~6.9 kg.