Audi revs up diesel race car Audi hopes 650-horsepower diesel race car will spark interest among Americans in gas-saving diesels. By Peter Valdes-Dapena, CNNMoney.com staff writer February 15, 2006: 4:19 PM EST NEW YORK (CNNMoney.com) - When you think of diesel, what comes to mind? Trucks, probably, and buses. Maybe a few German passenger cars. But a race car? A diesel race car sounds like an oxymoron. Diesels are made for hauling, but not racing. But that's what Audi will be entering in this year's American LeMans endurance race series. The R10 race car is powered by a 5.5-liter turbocharged aluminum V-12 diesel engine capable of producing 650 horsepower. The car's first race will be a 12-hour event in Sebring, Fla. on March 18. Audi produced the car in large part to get the attention of U.S. car buyers. While diesel engined cars are popular in Europe, largely because of their extremely good fuel mileage, they are not nearly as popular in the United States. In this country, gasoline/electric hybrid engines have become the powerplant of choice for those interested in saving fuel. Part of the reason that diesel hasn't taken off here is that diesel engines are perceived by American consumers as slow, noisy and smelly, experts say. Significant improvements Diesel engine technology has improved significantly in the last few decades, however, and modern diesel engines don't produce the clatter and smoke that older engines did. They also accelerate faster, thanks to turbocharging and other performance improvements. Audi hopes to make that point clearly with the R10 race car while also pushing more improvements in diesel technology, the company said. One advance already made is the engine's aluminum construction, the company said, the first for a diesel engine. Increased fuel efficiency, which would mean fewer stops to refuel, could be a factor in winning endurance races, but the R10's diesel engine won't give Audi a large fuel economy advantage, said Rod Bymaster, director of Audi's North American motorsports operations. In ordinary driving, a diesel engine can offer a 20 to 25 percent advantage in fuel economy, he said. Diesel engines lose much of their fuel economy advantage when running at full speed, however, as they are much of the time during a race.