FTC FACTSfor Consumers

AUTOMOBILES

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FEDERAL TRADE COMMISSION FOR THE CONSUMER

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A re you tempted to buy a high octane gasoline for your car because you want to

improve its performance? If so, take note: the recommended gasoline for most

cars is regular octane. In fact, in most cases, using a higher octane gasoline

than your ownerís manual recommends offers absolutely no benefit. It wonít make your

car perform better, go faster, get better mileage or run cleaner. Your best bet: listen to

your ownerís manual.

The only time you might need to switch to a higher octane level is if your car engine

knocks when you use the recommended fuel. This happens to a small percentage of cars.

Unless your engine is knocking, buying higher octane gasoline is a waste of money, too.

Premium gas costs 15 to 20 cents per gallon more than regular. That can add up to $100

or more a year in extra costs. Studies indicate that altogether, drivers may be spending

hundreds of millions of dollars each year for higher octane gas than they need.

What are octane ratings?

Octane ratings measure a gasolineís ability to resist engine knock, a rattling or pinging

sound that results from premature ignition of the compressed fuel-air mixture in one or

more cylinders. Most gas stations offer three octane grades: regular (usually 87 octane),

mid-grade (usually 89 octane) and premium (usually 92 or 93). The ratings must be

posted on bright yellow stickers on each gasoline pump.

The Low-Down

on High Octane

Gasoline
October 2003

F C EDERAL RADE OMMISSION T FTC OR HE ONSUMER

1-877-FTC-HELP www.ftc.gov

Facts for Consumers

Whatís the right octane level for your

car?

Check your ownerís manual to determine the

right octane level for your car. Regular octane is

recommended for most cars. However, some cars

with high compression engines, like sports cars

and certain luxury cars, need mid-grade or premium gasoline to prevent knock.

How can you tell if youíre using the right octane

level? Listen to your carís engine. If it doesnít

knock when you use the recommended octane,

youíre using the right grade of gasoline.

Will higher octane gasoline clean

your engine better?

As a rule, high octane gasoline does not outperform regular octane in preventing engine deposits

from forming, in removing them, or in cleaning

your carís engine. In fact, the U.S. Environmental Protection Agency requires that all octane

grades of all brands of gasoline contain engine

cleaning detergent additives to protect against the

build-up of harmful levels of engine deposits

during the expected life of your car.

Should you ever switch to a higher

octane gasoline?

A few car engines may knock or ping ó even if

you use the recommended octane. If this happens,

try switching to the next highest octane grade. In

many cases, switching to the mid-grade or premium-grade gasoline will eliminate the knock. If

the knocking or pinging continues after one or

two fill-ups, you may need a tune-up or some

other repair. After that work is done, go back to

the lowest octane grade at which your engine runs

without knocking.

Is knocking harmful?

Occasional light knocking or pinging wonít harm

your engine, and doesnít indicate a need for

higher octane. But donít ignore severe knocking.

A heavy or persistent knock can lead to engine

damage.

Is all ìpremiumî or ìregularî gasoline

the same?

The octane rating of gasoline marked ìpremiumî

or ìregularî is not consistent across the country.

One state may require a minimum octane rating

of 92 for all premium gasoline, while another

may allow 90 octane to be called premium. To

make sure you know what youíre buying, check

the octane rating on the yellow sticker on the gas

pump instead of relying on the name ìpremiumî

or ìregular.î

For More Information

If youíre concerned about the accuracy of an

octane label ó or if you donít see a yellow

octane sticker on a gasoline pump, write: Consumer Response Center, Federal Trade Commission, Washington, DC 20580.

The FTC works for the consumer to prevent

fraudulent, deceptive, and unfair business practices in the marketplace and to provide information to help consumers spot, stop, and avoid

them. To file a complaint or to get free information on consumer issues, visit www.ftc.gov or

call toll-free, 1-877-FTC-HELP (1-877-382-

4357); TTY: 1-866-653-4261. The FTC enters

Internet, telemarketing, identity theft, and other

fraud-related complaints into Consumer Sentinel,

a secure, online database available to hundreds of

civil and criminal law enforcement agencies in

the U.S. and abroad.

Produced in cooperation with the American Automobile Association