Financial Education


Does Premium Gas Make Your Car Run Better?

Jerry Edgerton / February 6th, 2017

Do you buy premium gas for your car occasionally even if the owner’s manual calls for regular gas? If you do, you’re wasting your money on that premium buy, according to AAA.

The auto club report finds that Americans are wasting $2.1 billion a year buying premium gasoline when their car only needs regular.

Researchers extrapolated from a consumer survey to determine that 16.5 million motorists filled up unnecessarily with premium an estimated 270 million times in the last year.

An urban myth has grown up that “treating” your car at least occasionally with premium gas is a good idea. This notion may have started in the 1950s when premium gas contained a tetraethyl lead additive that prevented engine knock and helped engines run cleaner. It was promoted with slogans like: “Speedway is going steady with Ethyl.” Now all grades of gas are required to have engine-cleaning additives, excluding the toxic lead compound.

Having determined how many motorists were buying premium gas in place of regular, AAA continued with laboratory research to see if that premium gas conferred any benefits. Using a dynamometer—essentially a  treadmill for cars—researchers determined that using premium in cars only requiring regular did not increase power or gas mileage nor cut down on polluting emissions.

“Drivers see the ‘premium’ name at the pump and may assume that the fuel is better for their vehicle,” says John Nielsen, AAA managing director of automotive engineering and repair. “Premium gasoline is higher octane, not higher quality.”

The AAA research came up with these additional findings:

  • Seventy percent of Americans drive cars that only need regular gasoline. Sixteen percent require premium fuel while the remaining 14% need mid-grade gas or have an alternative power source like electric batteries.
  • Modern engine control systems can adjust automatically to deal with any problems from lower-octane gas—a capability not available in earlier decades.
  • Timely maintenance on the schedule suggested in the owner’s manual will help keep gas mileage higher and help the engine run better.

AAA did not address the opposite premise: Will it hurt my car to save money by using regular gasoline when premium gasoline is called for?

But the automotive website Edmunds.com has done research about the topic. Their take: If your owner’s manual says premium gas is “recommended,” it should be fine running on regular. If, however, premium fuel is “required,” stick with the recommendation. Regular gas could overheat and eventually damage such engines.