Racing machines are fine-tuned pieces of iron that run hotter and faster than any street-based grocery getter. And now another class of these fast-moving bullets will be powered by ethanol, yet the change is that the biofuel in these high-powered beauties comes from cellulose.
The Corvette racing team has a commanding presence in the American Le Mans series and starting in April, those cars will be powered by E85.
Corvette Racing announced this week that in its next GT1 race at St. Petersburg, Fla., in April, the team will be powering its vehicles with E85 fuel. This is a demanding race through the streets of St. Petersburg in the Acura Sports Car Challenge and the second in the season series.
This isn't the E85 you get at the corner convenience pump. The ethanol is mixed with high-test racing gas to power these big machines. But the fuel does offer some of the same challenges users have discovered in regular day-to-day use.
"Ethanol, on a volume basis, has less energy than what we're accustomed to running," comments Doug Fehan, manager, General Motors Racing program. "We also had some challenges developing a fuel cell that will hold the fuel. But we have reached that goal for St. Petersburg."
A racing fuel cell, or "gas tank" is a highly specialized tool. Turns out the ethanol blend was causing issues with the adhesive in the cell creating issues with the cell breaking down. Those problems have been solved, and they're not problems normal drivers would find in their own cars since gas tanks are a lot different in design.
But the new fuel did cause a challenge in how much they needed to carry to be competitive. Racing rules allow only a maximum of 110 liters - about 29 gallons. Most cars using standard racing fuel will carry about 90 liters - or about 24 gallons. For the Corvette team to compete and not add more pit stops for fuel, they've ramped up their tank capacity to 105 liters.
Cars in the series not running E85 will keep their smaller fuel cells, however, their cars will be ballasted so they don't get a weight advantage over the Corvette that could be carrying an extra 40 pounds when the green flag drops.
As for performance? "There is virtually no difference in horsepower and torque burning the E85," Fehan says. The biggest change was to increase the volume of fuel that enters the combustion chamber to match the energy offered in traditional fuel. Fehan says that required only small changes in the engine fuel system.
As for the choice of cellulosic ethanol? This fuel is made from wood waste by the KL Process Design Group in Rapid City, S.D. and they will supply the entire American Le Mans series with cellulosic E85 racing ethanol for the 2008 season.
Fehan notes that GM has a long history with flex-fuel technology and he claims the company has built the most flex-fuel vehicles on the market today. While the street-version Corvette won't be a flex fuel vehicle, the racing machines are. The choice of cellulosic ethanal "only makes sense" he notes.
"As any new energy source gets developed, a lot changes and a lot is in flux," Fehan adds. "The reality of it is cellulosic ethanol is made from scrap and garbage and its cheaper to produce and cost plays a key role in ethanol. We're happy to have cellulosic [ethanol]."
As for how the E85 racers handle? Driver Johnny O'Connell from the Corvette Racing Team doesn't see much of a change in pit strategy says there has been "no loss in performance at all." He adds that carrying a little more fuel makes the care heavier, but that the tires the cars run on haven't shown increased wear.