Ethanol race cars have power to burn

Source: By Jenny King, Special to the Chicago Tribune • Posted: Wednesday, June 12, 2013

E85 ethanol fuels a Chevy Corvette C6.R in the American Le Mans Series race at Mazda Raceway Laguna Seca in Monterey, Calif. (Richard Prince/ Corvette Racing photo)

Cars competing in the 10-race 2013 American Le Mans Series are, with one exception, using E10 or E85 fuel. But it’s not exactly the ethanol consumers find at their favorite filling stations.

“These fuels have 100 octane ratings,” says Scot Elkins, chief operating officer of the sports-car racing series.

A higher octane rating helps prevent pre-firing of an engine’s pistons and allows the race car to get more bang for the buck.

Cars using fuel with ethanol in the ALMS must commit to either E85 or E10 at the beginning of the season, Elkins says. If competing cars could switch back and forth during a season,he says his job a lot harder.

The International Motor Sports Association, which sanctions this series, has authorized four official fuels: clean diesel, gasoline, ethanol and isobutanol.

One car in 2013 is using isobutanol, a fuel that Elkins says shows great promise for consumer use.

“Basically the entire GT class uses E85, and every other car uses E10 with the exception of the No. 16 Dyson Racing Mazda-Lola, which uses isobutanol,” says ALMS spokesman Nate Siebens.

Corvettes are fueled by E85, Elkins says. General Motors made the call based on its marketing of flexfuel models.

E10 and E85 perform very differently, he says. Cars powered by E10 are allowed 90 liters of fuel per fill-up, while E85 users get 110 liters. They should be making the same number of pit stops for fuel, he said, but cars with E85 are carrying more fuel weight.

Heat takes its toll on engines, especially those in race cars. Ethanol is said to contain less heat energy than gasoline per volume, releasing less as it is burned.

The goal for each race — and races vary in specified times from two to 12 hours on dissimilar courses — is to go the farthest distance in the least amount of time. “It’s all about speed,” Elkins says.

The series provides a track-based laboratory for engines and fuels. Although a race car’s fuel economy is generally in the single digits, there are valuable lessons learned that will benefit the driving public.

The American Le Mans Series emphasizes “green” and is the only racing series recognized to comply with the Green Racing protocols developed by the U.S. Department of Energy, the U.S. Environmental Protection Agency and SAE International.

The next race on the ALMS circuit is the American Le Mans Northeast Grand Prix on July 6 in Salisbury, Conn.