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What is Flex Fuel?

What is Flex Fuel? What do E10, E15 and E85 Mean?

Flex Fuel seems like a great idea. Certain cars can run on different blends of gasoline and alcohol derived from crops like corn or sugarcane. Flex Fuel vehicles, mostly from the Big Three, began introducing the technology in the 1990s, but the technology didn’t really mature until after the 1970s.

Flex Fuel has a lot of corn.

Flex Fuel capable vehicles can operate on E85, a mix that’s as high as 85% alcohol and just 15% gasoline. Almost all cars are using a gasoline mix. It isn’t always the case that most gasoline sold in the U.S. is E10

E15 has been approved by the EPA. The proposal to increase the amount of ethanol by 50% was opposed by a coalition of auto manufacturers. The EPA deems E15 safe to use in 2001 and newer cars, but there has been conflicting research on whether or not it is harmful. Many people said at the time that they wouldn’t honor warranties if owners used E15.

How to identify a Flex Fuel vehicle.

Flex Fuel vehicles have either a yellow fuel cap or yellow ring on their capless fuel tanks. They may also have Flex Fuel badging on the vehicle. Flex Fuel vehicles can be purchased from the U.S. Department of Energy. The workhorses include the Chevy Sierra, Ford Transit Connect, F 150 and F 250. The only standard family car on the list is the Ford Explorer, and you can find some Flex Fuel cars on the used market.

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Flex fuel pros.

Flex Fuel seems to be the perfect solution for extending a finite resource and reducing dependence on foreign oil by stretching the amount of actual gasoline used. It was originally thought of as a green solution since it was derived from renewable biomass.

The octane rating of E85 is higher than that of premium fuel. That means the fuel can resist earlier than expected, and thus burns more completely, and a cleaner burn means less emissions at the tailpipe. While performance engines typically have higher compression ratios, the current crop of E85 compatible vehicles are not sporting machines that can take advantage of the higher octane.

Flex Fuels use less oil. The national average for E85 is about 80 cents less than E10, the most common type of fuel. You can check your local listings for prices.

Flex Fuel isn’t a good thing.

If you have a Flex Fuel vehicle, it may seem like a no-brainer to use E85. It should be noted that fuel economy can be reduced by as much as 25% to 30%. Depending on the vehicle’s mpg rating and local price of E85, drivers will have to decide if the reduced fuel economy negates any savings at the pump.

Proponents claim that E85 is great for the environment, but maybe not. The corn industry has a powerful lobby in the US. In states like Iowa where corn is a major industry, there is a lot more E85 available.

Over the years, powerful corn lobbyists have won a lot of government subsidies, which in turn prompted many producers to grow the crop even though it is less efficient to produce than sugarcane.

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The environment would be better off if cars just burned straight gasoline, according to a study in the Proceedings of the National Academy of Sciences. We would be better off using the resources corn takes up to grow crops that feed people. If it were possible to make it economically from corn stalks and other sources, it would be a good thing.

I don’t know if I should use Flex Fuel.

Don’t use E85 if your vehicle wasn’t built as a Flex Fuel vehicle. The engine parts and fuel system will be damaged. It’s probably best not to use E15 if you have an older vehicle or don’t know if it’s compatible with your car.

Does it hurt cars?

Many sources, including the U.K.’s Royal Automobile Club, say that E10 can damage cars older than the 2002 model year. It can damage fuel systems that weren’t designed for anything other than pure unleaded gasoline. Fuel tanks, gasket and seals, and other rubber or plastic components could all be damaged.

It is not a guarantee of damage and how susceptible your vehicle is will likely depend on the age and model. If this is a concern for classic car owners, they can either use an ethanol conditioner and stabilizer or find one of the few remaining gas stations that offer free fuel.