Premium gas provides no benefit to cars that use regular, AAA study finds

Research by AAA has found that motorists wasted $2.1 billion in 2015 buying premium gasoline for cars that don’t require it.

Using tests designed to evaluate vehicle performance, fuel economy and emissions, AAA researchers said they found no benefit to using premium gasoline in a vehicle that only requires regular-grade fuel.

“Drivers see the ‘premium’ name at the pump and may assume the fuel is better for their vehicle,” said John Nielsen, AAA’s managing director of Automotive Engineering and Repair. “AAA cautions drivers that premium gasoline is higher octane, not higher quality, and urges drivers to follow the owner’s manual recommendations for their vehicle’s fuel.”

About 16.5 million U.S. drivers used premium gas despite the vehicle manufacturer’s recommendation that they use regular, AAA stated.

The majority of U.S. drivers, about 70 percent, own cars that require regular gas. About 16 percent drive vehicles that require premium, and the remaining 14 percent have cars that require midgrade gasoline or use an alternative energy source.

In partnership with the Automobile Club of Southern California’s Automotive Research Center, AAA tested regular and premium gasoline in vehicles equipped with a V-8, V-6 or I4 engine designed to operate on regular-grade fuel.

Researchers tested the vehicles on a treadmill for cars, called a dynamometer, to evaluate the effects of using premium in cars that did not require it. The lab testing found no significant increase in horsepower, fuel economy and tailpipe emissions.

“Premium gasoline is specifically formulated to be compatible with specific types of engine designs, and most vehicles cannot take advantage of the higher octane rating,” said Megan McKernan, manager of the Automobile Club of Southern California’s Automotive Research Center.

“Using premium fuel in a vehicle designed for regular is like throwing dollars out the window while you are driving,” McKernan said.