Photo courtesy General Motors
ZR1 Engine and Transmission
Though the supercharger on the ZR1 is one of its standout characteristics, its LS9 engine is no slouch, either. The engine shares its basic 6.2-liter design with other Corvettes but features some extra high-end materials and parts that are lighter and stronger than conventional engine parts -- like a forged steel crankshaft, steel main bearing caps, titanium connecting rods, forged aluminum pistons and roto-cast cylinder heads that have a more consistent density than other heads. There's more titanium on the intake valves (to save weight without losing strength), and the stems on the exhaust valves are hollow. Even the engine's flywheel has been modified for supercar duty. The flywheel on base and Z06 Corvettes is attached to the crankshaft with six screws, while the ZR1's is attached with nine.
Sending the engine's power to the wheels is a six-speed Tremec TR6060 transmission with a close-ratio gear set. On the ZR1, the gearing is 16 percent longer than that of the Corvette Z06, which means the ZR1 can get to over 60 mph without leaving first gear. For higher gears, the spread on the ZR1 is 26 percent shorter than the Z06. Though this makes for a lower redline in fifth and sixth, it also means the ZR1 easily scoots to over 200 mph. To further handle the engine's torque output, the gear, shaft gear and shaft materials were strengthened, and a twin-plate clutch was used to improve shift feel.
The ZR1's chassis is similar to the Corvette Z06. It uses the same aluminum structure but has some carbon fiber components to offset the engine's extra weight (hey, superchargers can be heavy). The ZR1 also has GM's Magnetic Selective Ride Control System, which allows drivers to select the type of suspension responses they prefer. On the ZR1, the system uses Magneto-Rheologial shocks, which adjust automatically based on driving conditions for optimal ride and control. The ZR1 also has stiffened and larger anti-roll bars. All together, the suspension system is designed to make the ZR1 a comfortable road car that can provide blistering track times.
Of course, a car like the ZR1 needs maximum stopping power. Its front brakes are 15.5-inch carbon-ceramic rotors, and the back rotors are 15 inches. Both are radially and laterally vented discs (to avoid too much heat) and were originally designed for the Ferrari FXX and Enzo. The calipers are Brembo monoblocs with six pistons in front and four in the back.
Connecting the ZR1 to the road are larger tires than on other Corvettes. The ZR1 has Custom Michelin Pilot Sport 2 run-flat tires on the front. They sit on 10-inch, one-piece 20-spoke rims from Speedline and measure 285/30R-19. In the rear, the tires measure 335/25R-20 and sit on 12-inch Speedlines.