Using Premium Gas in a Regular-Gas Engine Burns More Than Fuel

CARS.COM — Here’s a gallon of premium advice at regular price: Stop filling your tank with pricier gas than it requires! According to a just-released study from travel-services provider AAA, 16.5 million U.S. drivers burned (read: wasted) more than $2.1 billion on premium-grade gas last year alone despite their vehicles’ manufacturers recommending just regular ol’ regular unleaded.

Related: If My Car Recommends Regular Gas, Is It Good to Use Premium Occasionally?

“AAA conducted a comprehensive fuel evaluation to determine what, if any, benefit the practice offers to consumers,” researchers stated. “After using industry-standard test protocols designed to evaluate vehicle performance, fuel economy and emissions, AAA found no benefit to using premium gasoline in a vehicle that only requires regular-grade fuel.”

For the study, researchers tested vehicles equipped with V-8, V-6 and four-cylinder engines using 87-octane (regular) and 93-octane (premium) gas. Each vehicle was tested on a dynamometer using both types of fuel in varied driving conditions.

More than two-thirds of respondents reported driving a vehicle that calls for regular gas, and 14 percent midgrade gas or alternative energy such as electricity.

“Higher-octane fuels are formulated to be compatible with specific engine designs that are typically found in high-performance or luxury vehicles,” AAA stated. “Currently, fewer than 20 percent of vehicles on the road require high-octane fuel, while the vast majority of vehicles are designed to operate on regular gasoline.”

On average, AAA reported, drivers who errantly upgraded to premium did so at least once a month — for a total of about 270 million ill-advised fill-ups among U.S. motorists in 2015. AAA speculated that consumers conflate the terms “premium” and “better” when making their fuel-grade selections at the pump. In reality, however, they already made their fuel choice when they purchased their vehicle, which is to say, whatever the automaker recommends.

If car owners want to get the best performance from their vehicle, AAA instead recommends keeping maintenance up-to-date according to the manufacturer-recommended schedule.