Experts say higher octane ratings, higher price avoidable

Monday, August 11, 2003 | 12:00 a.m. CDT; updated 3:57 a.m. CDT, Friday, July 11, 2008

Drivers across the country are spending millions of dollars each year for higher octane gasolines that they may not need.

When customers pull up to the pump to fill up their tank, they’re usually given three options for gas: regular, super, and premium with octanes of 87, 89, and 91, respectively.

Although customers at the pump may feel as if they are paying a lot of money for regular unleaded gasoline, the price is now 19 cents less per gallon than it was in mid-March. Current prices are still about 20 cents more per gallon than at this time last year, however, and that may be causing some motorists to wonder if paying more money for higher octane gasoline is worth it.

According to some local experts, paying more for higher octane gasoline is not always necessary.

Mike Mountjoy, service manager at Perry Chevrolet in Columbia, said virtually every car that Chevrolet currently makes is designed to run on regular unleaded gasoline, or 87 octane.

“Putting high-octane gasolines in these cars can hamper the effectiveness of the vehicle,” he said.

When put into engines made for low-octane fuel, high-octane fuels can burn too hot and create a varnish in some of the components of the engine.

Even the high-performance engine found in Chevrolet’s Corvette sports car “runs fine on 87,” Mountjoy said, although 89 or 91 octanes are recommended in the manual.

He also recommended that automobile owners check their car’s owner’s manual for more information about the proper octane for their vehicle.

Octane, a measure of a gasoline’s ability to resist knock and pinging noises produced by the engine, according to the American Petroleum Institute. The higher the octane number, the less susceptible the car’s engine will be to engine knock. Newer vehicles are now equipped with a knock sensor that reduces engine knock. Premium gasoline can help performance in these cars.

The gas becomes a higher octane by adding refining steps during production. These steps produce a different blend of hydrocarbons and make the gas less susceptible to ignition, thus reducing the possibility of knock.

Ford Motor Co. also recommends 87 octane fuel in all of its vehicles, except for the Ford Mustang Cobra and Lincoln LS, for which 91 or higher is recommended, according to Mike Vaughn, public affairs manager for global technology at Ford.

Vaughn also emphasized that if drivers notice their engines producing knocking or pinging noises, they should either switch gasolines or see their dealer.

“Over time, engine knock can cause damage to your engine,” he said.

While most cars run fine on regular unleaded, the owners manuals for many high-end cars do recommend the use of premium gasoline.

Chuck Wright, service manager at Legend Automotive Group in Columbia, which sells and services Mercedes-Benz vehicles and others, said Mercedes recommends premium octane gasoline for its cars.

“For the car’s best performance, premium fuel is recommended,” Wright said. Wright said the use of regular octane fuel in luxury cars such as Mercedes-Benz, however, will not necessarily cause the car any harm.

Bob Tzou, MU professor and chairman of the MU Department of Mechanical and Aerospace Engineering, has a different perspective. He said the use of premium octane fuel can definitely show benefit for drivers in the long run.

“In regular use, I don’t think people will see much difference, but in certain severe uses, drivers might notice a slight benefit,” he said.

Some examples of these situations might be while towing or driving one’s car on a hot day.

“(Cars) would definitely benefit in the long run” by using higher octane gasolines, Tzou said.

Rex Bedwell filled up his Chevrolet Tahoe SUV Thursday afternoon with regular unleaded at the Phillips 66 at the corner of Stadium Boulevard and Bernadette Lane. Bedwell, passing through Columbia on his way to show horses, said he alternates between the three gas qualities when he fills up. For him, price is most important.

“I change around — one time I use the cheap stuff and the next I might use the premium, depending on the price,” he said.

No matter what kind of gasoline motorists use, some experts say octane selection has more to do with the economy than it does with car performance.

John Felmy, chief economist and director of policy analysis and statistics at the American Petroleum Institute, said the demand for premium gas tends to fluctuate with the economy.

“Around 1993, premium was almost 20 percent of the demand,” Felmy said. “As prices tended to increase, we have seen premium’s share in the market continually erode.”

In 2002, premium gasoline held a 13.5 percent market share in the gasoline market, according to the U.S. Energy Information Administration. As a comparison, regular gasoline held 80.1 percent of the market.

And according to the Federal Trade Commission, premium gas costs an extra 15 to 20 cents more than regular fuel on average, and in many cases, this may be money better spent elsewhere.

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