Top Stories
Top Stories
Oil and Gas

Cheap gas is great—unless you buy premium

Chris Maurer, Managing Producer

People who drive a turbo or other high-end car that needs premium gas could be forgiven for asking, what cheap gasoline?

Getty Images

The gap between regular and premium is now about 40 to 70 cents per gallon, the widest it's been since 2008.

"I don't like it," said Fred Tan of Dumont, New Jersey, as he filled up his 2010 Volkswagen GTI with premium grade gasoline, "But my car requires it."

For years, the difference between regular and premium stood at only about 10 cents per gallon, but that gap has widened for reasons of pure supply and demand. Far more motorists now buy regular fuel, and that volume helps keep regular gasoline cheaper.

Read MoreCan Apple give Tesla a 'run for its money'?

Statistics from the U.S. Energy Information Administration show only about 10 percent of gasoline purchased in the United States is premium. Twenty years ago, premium purchases were nearly double that, at 19 percent.

"Premium gasoline has become a 'boutique' fuel," said Patrick DeHaan of GasBuddy.com. "Folks now understand that unless it's specifically required by the manufacturer, a higher octane won't give them better gas mileage or better performance."

VIDEO2:3902:39
Low gas = auto sales boom?

"A lot of people switched to regular during the recession," he added. "Once you make that switch from premium to regular, it's hard to go back."

When there's less premium consumption, refineries reduce production. When premium inventories are tight, the grade gap soars. That divergence also rises when stations sell inventories of premium that were purchased when crude prices were much higher.

Read MoreOil layoffs could come back to haunt the industry

For consumers whose cars require premium, it makes sense to shop around. But that isn't always easy, because many stations advertise only their prices for regular grade gasoline.

Aside from GasBuddy.com other comparative pricing sites exist including gasprices.mapquest.com.