Why Racecar Drivers Prefer Ethanol

E85 Pumps ( Charles Johnson )

NASCAR continued using leaded gasoline until 2008—40 years after it was banned from consumer fleet because of brain toxicity. Ever wonder why it took the sport so long to make the switch?

It comes down to a whole lotta science that helps cars go fast. In simple terms though, they needed the octane.

“They key to high performance engines is octane,” says Andy Randolph technical director for ECR engines. “We were never real comfortable with [leaded gasoline] because we’re touching and breathing and intimately involved in fuel every day. In 2008 NASCAR adopted unleaded gasoline and achieve the octane [needed] with high concentrations of aromatic hydrocarbons like benzene and toluene—known carcinogens.”

Randolph joked he’s not sure if they really improved the situation that much, switching from a brain toxin to a cancer agent, but it got the ball rolling.

“In 2011, NASCAR finally had the foresight to adopt ethanol as the octane enhancer,” Randolph says. “Ethanol is the safest, most cost-effective octane enhancer out there.”

Currently NASCAR uses a 15% ethanol blend, with discussions about bumping that number up to 30%.  If NASCAR makes this switch, Randolph says there will be zero total rebuilds on engines, just a little recalibration on fuel injectors.

There’s a common theory about ethanol that says using it decreases your fuel efficiency—if that’s the case, why does NASCAR employ this fuel?

“People tend to want to look at something on a volumetric basis,” he says. “Efficiency is really defined as the power you get out, or the energy you get out, of something compared to the energy that you put in.

“Now, ethanol does have a slightly lower energy content than gasoline, so you have to use a little bit more. But as far as efficiency, the percentage conversion of that energy into the fuel, to what turns into mechanical energy in the engine: ethanal is actually a little bit more efficient than gasoline,” the Richard Childress Racing engine performance lead continues.

The switch to ethanol is making NASCAR events more green, too.

“There’s a big difference between the way ethanol and gasoline burns,” Randolph says. “Just hydrogen and carbon atoms make up gasoline molecules and ethanol has carbon, hydrogen and also oxygen. Oxygen is key to combustion. When you have oxygen in fuel, it helps you get a more efficient combustion in terms of converting all of that carbon and hydrogen to carbon dioxide and water. Emissions of things like unburned hydrocarbons and carbon monoxide go way down.”

Check out more of Randolph’s story on AgriTalk: