What is a "flex-fuel vehicle," anyway?

A flex-fuel vehicle is one that's designed to run on either 100% gasoline like every other car, or a mix of gasoline and up to 85% ethanol. E85 contains 85% ethanol and 15% gasoline.

Flex-fuel vehicles will not run on compost, rotting llama dung or anything found in Willie Nelson's bus.

Why am I hearing so much about "flex-fuel" and E85 all of a sudden?

Here's one reason: the federal government has started giving manufacturers a financial incentive to produce flex-fuel vehicles. By selling flex-fuel vehicles, they earn credits towards their mandatory CAFE fuel economy requirements. So by making vehicles that accept flex-fuel, they can sell more gas guzzling, but higher-profit SUVs without incurring penalties.

Then, there are all the other reasons why flex-fuel vehicles and E85 are gaining in popularity: ethanol isn't imported from the Middle East, it's somewhat more environmentally friendly, and it's aggressively marketed by special interests like the Amalgated Corn Growers Association.

Isn't ethanol already being used in gasoline?

It is. It's mixed into gas in a ratio of 10% ethanol and 90% gasoline. This mix, called "E10," represents about 10% of the gas that's sold in the US. E10 burns cleaner than 100% gasoline, reducing smog.

In fact, only about 1% of the ethanol now being made goes into making the E85 fuel. The rest goes into making E10.

Which cars can use E85?

Right now, there are about two dozen models that can run on E85 — mostly American-made SUVs and trucks. You can get a full list, here.

In the next few years, we expect many more vehicles to be flex-fuel ready, and able to run on either regular gasoline or E85.

Can you adapt a regular car to run on E85?

Not without a chemistry degree, money to burn, and plenty of free time.

The materials in your car's fuel system, including plastics and aluminum, need to be designed to handle ethanol. Some components, such as rubber o-rings and gaskets might wear out more quickly or suffer damage, if exposed to ethanol.

Your car's injectors also need to be changed, along with the vehicle's computer.

The changes are relatively inexpensive when done on a mass production basis at the factory. But we wouldn't recommend you try to retrofit a car for E85 at this time.

How is ethanol made?

Right now, ethanol is made from the same corn that's grown to feed livestock. However, a new form of ethanol, called "cellulosic ethanol" is in the works. It'll allow ethanol to be made more efficiently, and from a much wider variety of plants and biowaste, so ethanol production won't have to displace acreage currently used to grow food.

Will it really help reduce our dependence upon foreign oil?

Yes — somewhat. And we suppose every bit helps. But, it's hard to imagine E85 being a substitute for all the oil we're currently importing.

In fact, using the entire US corn crop to make ethanol would only replace about ten percent of our oil needs today.

Corn-based E85 is a drop in the barrel. But, if cellulosic ethanol and other ethanol advances are successful, the reduction in imports could be more significant. And when combined with other substitutes for petroleum, it could be part of an energy-independence solution.

Is there enough ethanol to go around?

Not yet. The US barely has enough processing plants to make the ethanol it needs now. But more are being built-- quickly, too.

Is it taking away land that could be used to grow food?

Yes-- but only in that it uses "industrial" corn that would otherwise go towards feeding cows (which, in turn, feed large-assed Americans who drive SUVs).

Do I save money using E85?

No. In fact, it costs more. Here's why. There's less energy in a gallon of E85. A gallon of E85 gets you 27% less mileage than a gallon of old-fashioned gas. So, if you're used to getting 25 miles per gallon on regular gasoline, you'll only get a bit over 18 mpg on a gallon of E85. And, since the price for E85 is, roughly speaking, about the same as a regular gallon of gas, you get to pay, what? Thirty-seven percent more to travel the same distance!

Then why would I want to use E85?

Two reasons: reducing energy dependence and cleaning up the environment.

Since ethanol is manufactured within the US, it helps reduce — at least a little — our dependence on oil.

How much ethanol helps the environment is up for debate. First, it takes a fair bit of old-fashioned crude oil to grow the corn to make the ethanol. (Of course, the same is true of regular gasoline. It takes oil to pump, ship and refine crude oil into gasoline.) Second, you don't get as much energy per gallon of fuel when E85 is compared to regular gas. So even though it's cleaner, you burn more of it to go the same distance.

Finally, while E85 emits fewer nitrous oxide emissions per mile, it does introduce a new category of pollutants, called aceta-aldehydes, which contribute to ozone problems. While most scientists agree that ethanol reduces the overall pollution to the environment, it's not without its own drawbacks.

Any special repair or maintenance concerns?

Unfortunately for those of us in the auto repair business, there are not any special repair or maintenance concerns that we know of, as yet. In time, we hope to discover at least a few major, boat-payment-sized repairs!

Where can I get E85?

Almost nowhere.

Right now, it's for sale in the Midwest near, not surprisingly, all the corn. There are 176,000 gas stations in the US — and about 800 that sell E85. If you don't have a corn farm within 20 miles of you, your odds of finding Jimmy Hoffa might be better. Of course, that may change, but for now that's the reality.

If you want to see if E85 is available in your neighborhood, try out this handy locator.

How do I know if a flex-fuel car makes sense for me?

If you're shopping for a new car and the model you're looking at is available in a flex-fuel edition, we'd advise you to go for it. It'll be a little more money but if E85 becomes more widely available, you'll be ready to start fueling up with corn.

However, we wouldn't suggest changing your new car plans just to get a vehicle that's E85-ready. Most of the current crop of flex-fuel vehicles are large SUVs or trucks, which are notorious for their poor fuel economy.

Anything else I should know?

Yes, as a matter of fact. Three items come to mind:

Item #1: On cold mornings, when the temperature is below freezing, a car that's got E85 in the tank will run rough until the engine gets up to operating temperature. E85 won't prevent the car from starting, but it will cause it to stall several times.

Item #B: Some fuel additives are not compatible with E85. So, if you're used to tossing in a quart of Dr. Bronner's Peppermint Engine Salve, think twice.

Item #III. Some manufacturers recommend that you not tow a vehicle when you have E85 in the tank. If you're hauling your yacht to the harbor, you'll want to use regular unleaded.