After a decade of competing with the GT1 big dogs in the American Le Mans Series and the 24 Hours of Le Mans, this weekend marks the start of a new era for Corvette Racing. The race at Mid-Ohio this Saturday (we'll be on hand live) will mark the debut of the all-new GT2 Corvette C6.R. For the last two years, the Corvettes have run without any factory competition in the ALMS GT1 class, and with GT2 being where all the action is, Chevrolet has decided the time was ripe for a change.

The original GT1 C5R debuted in 1999, and in 2005, the team transitioned to the then-new C6.R body style. Over the years, competitors like the Dodge Viper, Aston Martin DBR9 and Ferrari 575 have come and gone, but the Vettes have soldiered on to fight the good fight. After farewell races at Sebring, Long Beach and Le Mans earlier this year, the GT1 cars have been retired. Mark Kent, GM Racing manager, Doug Fehan, Corvette Racing program manager, Tadge Juechter, Corvette chief engineer, Johnny O'Connell, driver No. 3 Compuware Corvette C6.R all took part in a conference call today to discuss the move to GT2, and we were on the line

Although GT1 remains relatively popular in European racing, GT2 has become the dominant class here in North America. GT2 cars are less powerful and closer to the production models in dimensions and powertrain configuration. The Ferrari F430 GT and Porsche 911 GT3 have dominated GT2 for the past several years, although a number of other models have been coming on strong recently. This year, factory supported BMW M3s joined the fray as did least two Ford GTs in 2008. A new Jaguar XK should be appearing before the end of the season as well.

The new GT2 car switches from bodywork derived from the roadgoing Z06 to something that looks more like a ZR1. GT2 rules prohibit some body modifications like the reshaped headlights and wider fenders that were present on the outgoing GT1. Instead. the fenders on the new GT2s are now dimensionally identical to the production ZR1. Aerodynamically, GT2 mandates a smaller front splitter and rear wing, changes that manifest themselves as less downforce.

Under the skin is where the biggest changes have taken place. The GT1 used a steel chassis modeled on the base Corvette, while the GT2 switches over to an aluminum chassis based on the production Z06/ZR1. That posed some serious technical issues for the design team in attaching the necessary steel roll cage to the aluminum. According to Corvette Racing manager Dough Fehan, the team has come up with a novel approach to the problem that should make the new car even safer in the event of a crash. Unfortunately, Fehan declined to give details today.

Many of the GT2 rules differences are aimed at lowering cost. Thus, the carbon brakes of the GT1 have given way to more traditional steel brake rotors on the GT2 car. One of the advantages of going to a more production-based platform for the drivers will be the inclusion of a power tilt and telescoping steering column. That will help drivers of different sizes get more comfortable in the car.

Propulsion for the remainder of the 2009 ALMS season comes from a downsized 6.0-liter version of the 7.0-liter V8 that has been running in the GT1 car. The bore size remains the same, with the primary change being a shorter stroke crankshaft. For 2010, some new engine rules in GT2 will mean an all-new engine for the Corvette. Come Sebring next March, the GT2 Vettes will be running a new 5.5-liter V8 based on the next-generation version of the GM small block. Unlike the GT1 engines, the engines for the new cars will be assembled on the line at the GM Performance Powertrain Center alongside the production LS9 and LSA used in the ZR1 and Cadillac CTS-V.

The Corvettes will continue to run on cellulosic ethanol as they have since early in the 2008 season. On the subject of hybrid powertrains, Fehan emphasized that GM has as much knowledge as any manufacturer in the world on the technology. He acknowledged that the team has investigated such systems for the race cars, but he wouldn't commit to any future plans.

The team retains its current partners, with Compuware as the primary sponsor and Michelin and Mobil 1 supplying tires and lubricants. The GT2 Vettes will run the remainder of the 2009 ALMS season starting this weekend at Mid-Ohio and continuing to Road America, Mosport, Petit Le Mans and Laguna Seca. Just as before, the driver lineup stays the same with Johnny O'Connell, Jan Magnussen, and Antonio Garcia in #3 and Oliver Gavin, Olivier Beretta, and Marcel Fassler piloting the #4 car.