When it comes to filling up the gas tank with ethanol-blended fuel, lots of American drives pay attention to price, fuel economy and engine performance. The ethanol industry fights hard to shape public opinion of the fuel, and it has now found a new way to get its message across in a partnership with NASCAR.

This February, starting at the Daytona 500, NASCAR will be filling up with Sunoco Green E15 gasoline — a 15 percent ethanol gas blend. It’s got just a bit more ethanol than E10, what many gas stations today offer as regular fuel.

Ethanol trade group Growth Energy signed a six-year deal with NASCAR to promote the fuel.

So, if Jeff Gordon wins the Sprint Series on Sunoco Green E15, ethanol must be liquid gold, right?

 “They wouldn’t be going backward in choosing their fuel, none of these racing series would, and so it is a tremendous opportunity to demonstrate to consumers what a great fuel it is,” said Growth Energy CEO Tom Buis.

But Charles Drevna, president of the National Petrochemical and Refiners Association, argues that this is a “complete bastardization of comparison.” He’s part of a coalition fighting the Environmental Protection Agency’s recent green-light for 15 percent ethanol in some cars.

“To say well, NASCAR can use it, then the average driver can use it. No more than you can say, look if it is good enough for NASA to put rocket fuel in Challenger, then we can put it in automobiles, too. Completely different applications. Comp­letely different fuels,” he said.

For years, ethanol has been used as a fuel additive to boost octane. But at higher blends, Drevna said, ethanol makes engines knock and affects miles per gallon.

“A gallon of gasoline with take your vehicle a lot further down the road than a gallon of ethanol will,” he said.

Just this week, several major U.S. oil refiners - including Valero Corp. and Marathon Oil Corp. - said they will refuse to sell gasoline containing 15 pecent ethanol because because it could harm older automobiles or void their warranties.

As the ethanol and oil industry squabble, the word on the street is just as divided. Not everyone lines up happily to buy ethanol.

Here’s a small selection from among thousands of comments from one online community:

"I did a project for mechanical engineering last semester on ethanol and I don't want it anywhere near my engine.”

“I, for one, have noticed crappy mileage and a power loss running ethanol fuel

"I feel like I am being ripped off now by E10 gas."

Buis of ethanol’s Growth Energy, casually rejects this angry chorus of what he calls “misinformation.”

“The differences between E10 and E15 would be minimal at best if non-existent, or, probably more likely nonexistent in terms of miles per gallon,” he said.

But who to believe? To get that answer we’ll use an extreme example. Dan Edmunds is director of vehicle testing for auto-research website Edmunds.com.

To test ethanol fuel efficiency, Edmunds drove from San Diego to Las Vegas in a flex-fuel car. First, he fueled up at the neighborhood pump with regular E10 gasoline. Then he used E85, eighty-five percent ethanol. It’s available in small pockets throughout the country.

“On gasoline, we made the round trip with 36.5 gallons of gasoline,” he said, “and on E85 it took 50 gallons. Thirty-seven percent more fuel to make the round trip. Same distance, same vehicle.”

As ethanol replaces gasoline, you’ll likely make added stops at the gas station. Still, the ethanol industry cites its research which says otherwise.

It’s likely, though, that this fuel fight will rev up 2011 when the Department of Energy could approve E15 —similar to NASCAR’s new fuel — for use in more cars. 

And to meet the government’s renewable fuel mandate by the year 2022, the ethanol industry says all fuel needs more ethanol — its sweet spot is closer to E27. The National Renewable Energy Laboratory, in Golden, Colo., says at that level, drivers will experience a 10 percent drop in fuel economy.

More from this special report

Hope or Hoax: The Truth Behind the American Ethanol Debate