Sneak Peek: GM’s ALMS GT Challenger, The Corvette C6.R
By Mike Kojima
Dave Coleman gave you a sneak look inside GM’s Pratt and Miller built C6.R GT1 cars when he was at LeMans. We also happened to get a close look at the ALMS GT version of the cars when we were in the pits at the Long Beach Grand Prix in April. Although the Le Mans GT1 and ALMS GT cars look identical to the untrained eye they are actually pretty different machines under the skin.
|The GT car's bodywork is closer to production and not as radical as the GT1 car. The GT1 car's big splitter, split flow radiator ducting, big rear wing and louvered fenders were not allowed in GT. The wider body from the ZR1 was homologated although the supercharged LS9 engine was not!
The first major difference between the cars is that the GT1 car is based on the C6 base model Corvette with the production steel frame. The steel frame was chosen due to the ease of building a thorough safety cage, which was deemed safer for the high speeds of LeMans.
|The GT car has a much shorter diffuser without the vertical strakes of the GT1 car.
The ALMS car is based on the Z06 and ZR1 Corvette with its aluminum perimeter frame. It is much more difficult to incorporate a proper steel cage into the aluminum structure but the team has done so. All of the original chassis structure from the windshield frame, the hoop around the rear of the passenger compartment, the door hinge pillars, the drivetrain tunnel, the firewall, and the floor pan remains. The GT1 car weighs 2580 lbs while the GT car weighs 2745 lbs, probably due to its closer to production car heritage.
|The lower, shorter and narrower wing is readily apparent here.