Winning the Green Challenge: Corvette Racing’s Greatest Victory

By Tom Wallace
GM Global Vehicle Chief Engineer for Performance Vehicles
GM FastLane Blog


As an amateur sports car racer, Corvette chief engineer, and rabid racing fan, I’ve seen more than my share of winner’s circle ceremonies. I never thought I would see the day when the U.S. Environmental Protection Agency, the U.S. Department of Energy, and SAE International, the world’s leading automotive engineering organization, were awarding trophies at an auto race. I saw it happen on Oct. 4 at the conclusion of the American Le Mans Series’ Petit Le Mans sports car race at Road Atlanta in Braselton, Ga. And I’m proud to say that General Motors and Corvette Racing, Chevrolet’s factory team, received the winner’s trophies in the inaugural Green Challenge.

The Green Challenge was a “race within a race” during the 1,000-mile endurance event. The four ALMS classes made up of 37 high-tech race cars all took part. Racing is all about getting to the finish line first, but on this night it was also about performance, fuel efficiency and environmental impact.

Working with the EPA, DOT and SAE, the series organizers and the Argonne National Laboratory created a formula that calculated the winning entries in the Prototype and GT classes based on energy used, greenhouse gases emitted, and petroleum fuels displaced. In short, the Green Challenge recognized the fastest car with the smallest environmental impact.

Corvette Racing is America’s premier sports car racing team. Since its debut in 1999, the team has won eight consecutive ALMS championships and 73 races, including five class wins in the prestigious 24 Hours of Le Mans. From my perspective, winning the Green Challenge is the team’s most significant achievement to date.

After nearly 10 hours of racing, the No. 3 Compuware Corvette C6.R driven by Johnny O’Connell (Flowery Branch, Ga.), Jan Magnussen (Denmark), and Ron Fellows (Canada) posted the best overall score in the Green Challenge. In fact, the Corvette’s score was 50 percent better than the Porsche that won in the Prototype division.

Don’t think the Green Challenge was an economy run with drivers pussyfooting around the track to save fuel. Speed mattered, and it was a full-throttle, flat-out race before a record crowd. The class-winning GT1 Corvette completed 365 laps on the Road Atlanta course, averaging more than 95 mph for nine hours and 41 minutes.

I’ve never been prouder of General Motors and Corvette Racing than when Steve Wesoloski, the head of GM’s road racing programs, accepted the manufacturer and team trophies on the victory podium. It culminated a plan that began in January at the North American International Auto Show when Ed Peper, North American Vice President, Chevrolet, announced that Corvette Racing would use cellulosic E85 ethanol racing fuel in the 2008 season.

The important thing to know about the E85R fuel used by the Corvette race cars is that it is primarily cellulosic ethanol, made from wood waste collected in the Black Hills National Forest as part of a wildfire prevention program. Dead trees, broken branches and undergrowth that would otherwise be burned are converted to cellulosic ethanol at KL Energy’s plant in Wyoming. The conversion plant is energy self-sufficient, and actually supplies surplus electricity to the power grid.

Since the Green Challenge formula considered the overall environment impact of the fuel used from “well to wheel,” the decision to use second-generation cellulosic ethanol in the Corvette race cars’ 7-liter GM small-block V-8 engines was decisive in the Green Challenge victory. In fact, the greenhouse gas emissions for the winning Corvette was 170 percent better than the first non-E85 finisher in the GT class.

GM engineers and the race team analyzed every aspect of the race cars to minimize energy use by reducing friction, aerodynamic drag, and rolling resistance. They worked with our technical partners on lubricants to reduce power losses in the engine and drivetrain. They used sophisticated computational fluid dynamics programs to refine the body shape. They developed tires that trimmed rolling resistance without sacrificing traction.

Corvette Racing’s success in the Green Challenge proved the validity of E85 as a good choice for those of you who drive some of the 3 million GM flex-fuel vehicles on the road today. There is no silver bullet to our nation’s energy challenges, but nothing has done as much as ethanol to offset oil demand. It’s a practical solution being implemented today while we continue to develop promising new technologies for tomorrow. In the race to protect and preserve the environment, there is no finish line.