The new ALMS season is set to kick off at Sebring on March 20, and Corvette Racing will debut their new ZR-1 based race cars in the GT class (called GT2 at the 24 Hours of LeMans). Gone for 2010 is the GT1 class, which has been ruled by the Corvettes since the late 1990s. In the 2009 season, Corvette was the sole remaining entry in the GT1 class.
The most significant change from GT1 to GT2 is the reduction in displacement from 7 liters to 5.5 liters. Pratt & Miller, who builds the cars for Corvette Racing, achieved this by reducing the bore and shortening the stroke. Air restrictors (28.8 mm in diameter) are used in the intake tract to further limit horsepower.
What’s interesting is how much of the stock Corvette ZR-1 goes into building the race cars. The new C6.R GT car uses the ZR1 body design with a slightly modified front splitter and stock rear spoiler. Fender flares are required to accommodate the wider tires used, and the frame rails, windshield frame, passenger compartment hoop, door hinge pillars, drivetrain tunnel, firewall, floorpan, windshield and steering system are straight out of a ZR1 Corvette. Several of the ZR1’s features (such as carbon composite brake rotors and a supercharger) are outlawed under GT class rules; effectively, the C6.R needs to be made slower to compete in the class.
It’s been a long time since Corvette Racing has had to go wheel to wheel with Aston Martin, Porsche and Ferrari. The rule changes for the 2010 season should make for some entertaining racing.