Chevrolet Corvette ZR1 (C6) '09

The Chevrolet Corvette C6 ZR1 is a high performance version of the Chevrolet Corvette C6. Both the C3 from 1969–1971 and C4 Corvettes from 1990-1995 had ZR-1 models. However, the C6 variant is officially labeled as the "ZR1" while previous variants had a hyphen between the ZR and 1, as in "ZR-1".

Engine design
The Corvette ZR1 engine is a heavily modified version of the LS3, designated the LS9.Producing 638 hp (476 kW; 647 PS) and 604 ft·lbf (819 N·m) of torque, it is the most powerful production Corvette to date. The LS9 has a sixth-generation TVS Supercharger|Eaton TVS R2300 roots 4-lobe supercharger with intercoolers from Behr, utilizing an air-to-water, dual-brick design. The supercharger's four-lobe design offers improved efficiency over three-lobe models. To avoid changes to the hood appearance, the supercharger's output was split into two halves. Each cylinder bank has an intercooler.

The cylinder walls of the LS3 are thicker than the Z06's LS7 since the LS3 has a smaller bore. Oil squirters under each piston help lubricate the pistons and cylinder walls are used for the first time in a production Corvette. Connecting rods and the inlet valve are made of titanium. Heads are made from a special heat resistant aluminum alloy. The camshaft lift was reduced from the LS7's to improve idle quality. With the addition of the supercharger to the 6.2 liter LS9, the higher lift camshaft was no longer necessary to achieve horsepower targets.

Lubrication is provided by an improved version of the LS7's dry sump system. The new system increases oil capacity from 8.0 to 10.5 quarts (9.94 liters). A new dual gerotor oil pump increases scavenge performance and oil pressure, enabling oil to be delivered under the most extreme conditions. Due to the increased pressure, the Ultraguard Gold UPF48R oil filter is required. The LS7 oilpan is used for the LS9 with the addition of an oil cooler which is mounted on the left side of the pan.

With the 2011 model, GM offers the optional "Corvette Engine Build Experience," where the customer visits the General Motors’ Performance Build Center to help assemble the LS9 for the ZR1 purchased. Factory technicians supervise the process and the normal warranty covers the engine built by the customer's hands.

Transmission
The ZR1 flywheel has been improved over the 2008 Z06. The flywheel was upgraded by going from six to a nine bolt design and cutting off nearly 9.8 ounces (278 grams) for improved throttle response and acceleration.

The transmission is a 6-speed manual Tremec TR6060 with a MH3 gearset. The 2008 Z06 featured the MM6 gearset. Due to the gear ratios in the transmission and engine output, the Z06 reaches top speed in 5th gear, using 6th gear for gains in fuel efficiency at highway speeds; the ZR1 hits top speed in 6th gear.

Differential/drive
The differentia is a limited slip with carbon and steel plates. The differential uses SAE 5W-80 Dexron LS lubricant.

The two half shafts have different diameters (33mm left, 40mm right), designed to prevent resonanace during acceleration and reduce the chances of axle hop occurring.

Clutch
The ZF-Sachs twin-plate clutch supplants Z06's single-plate unit to reduce inertia for better shift feel. The lower clamping force reduces clutch-pedal effort. The clutch upgrade is considered a dramatic improvement over the unit employed within the Z06.

Brakes
The front brake rotors are similar carbon ceramic design as those employed in the Ferrari FXX track car, the difference being a diameter reduction from to for added wheel clearance. The front calipers are Brembo 6-piston units.

Rear calipers are Brembo 4-piston units. The rear brakes are carbon ceramic rotors, originally employed as the Enzo Ferrari front rotors. Same as those used in the BMW M3 GTS.

Both front and rear pads have twice the contact area of the Z06's, as well as the addition of brake pad wear sensors. The brake master cylinder, booster, ABS unit and system controller are now sourced from Bosch in place of Delphi.

As a result, the ZR1 will stop from in a current production car record breaking.

Ignition
Coil packs are identical to those used on the LS3. The coil packs are mounted on the valve covers.

Fuel system
A unique fuel pressure regulator varies pressure between and depending on rpm.

Identification
The ZR1 features blue badges, engine valve covers, and brake calipers. The hood contains a polycarbonate window which allows the intercooler to be viewable. Doors and rear body are from the 2008 Z06. A larger than previous model spoiler spans the top rear bumper. Functional fender vents provide engine cooling. The lettering "LS9 Supercharged" can be viewed on top of the plastic supercharger cover through the hood window.