Can I use lower grade gas to save money?

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Regular gas

Manufacturers recommend higher-octane fuel for most premium cars. But is it OK to use a lower-grade fuel as gas costs rise? Image: crowt59/Flickr/CC BY

As gas prices continue to soar across the nation, many drivers of premium cars may be considering switching to a cheaper grade of fuel to save money on the road. Experts say it is probably not a good idea.

Fuel price exceeds $4 early

Fuel prices rose to more than $4 a gallon in Washington, D.C. this week, well before the official summer driving season traditionally begins. It is the highest it has ever been this early in the year, the Automobile Association of America said Wednesday. That trend is likely to be expressed across the nation.

AAA Mid-Atlantic’s manager of public and government affairs, John B. Townsend II,  said in a statement:

“For goodness’ sake, it’s only March, and this is the earliest point in the year that pump prices have soared to this price level. It took five months to reach this in 2011, and that took place just on the cusp of the summer driving season. But this time around, for no apparent rhyme or reason other than exceptionally high crude oil prices, it is occurring less than three months into the year.”

Politicians debate gas prices

Meanwhile, President Obama has joined with Senate Democrats to push a measure that would end tax cuts that save rich oil companies $24 billion annually. Democrats are hopeful that removing tax breaks for big oil and promoting alternative engine technologies, the price of fuel could be driven down in the long run. Republicans say, however, that eradicating federal subsidies will cause the price to rise even higher in the short term.

Is downgrading the answer?

Is using a lower-grade fuel the answer? Some experts say that any initial gains at the pump — about 8 percent — will be lost in performance and efficiency as the engine tries to deal with the lesser-grade fuel. It may also cause expensive damage to the vehicle in the long run.

Premium fuel recommended

For those vehicles that recommend but don’t require using a premium grade, it can be done, according to Steve Mazor, manager of the Auto Club of Southern California’s Automotive Research Center. He said:

“If the owner’s manual says premium fuel is recommended, then you can switch down.”

Knock sensors protect engines

Knocks occur as fuel burns when it is not supposed to in the engine’s combustion chamber. That can be caused by using a lower-octane fuel and could damage an engine over time. However, most modern cars have knock sensors that adjust the engine’s timing to deal with the lesser-grade fuel. However, the vehicle does take a hit when it comes to fuel efficiency.

Loss of mileage

Mazor noted the fuel change could cause your premium vehicle to “drop fuel economy by a couple of tenths of a percent.”

Amy Sisoyev of Eagle Rock, Calif., started filling her 2001 Volvo S40 with regular gasoline when fuel prices began to rise in February. She said:

“I do get a lot more gas for my $40, and the difference in mileage isn’t enough so that I have to get gas a day or two earlier.”

Thomas Plucinsky, a spokesman for BMW, said:

“If you use fuel with the lower octane rating, our engines will deal with it. But why would you do it in a car like our 335i? You are not getting the power and performance you are expecting and paid for.”

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Premium fuel required

However, for cars whose manufacturers require the use of premium fuel, switching down is definitely a mistake. Harold Schock, director of the Engines and Automotive Research Labs at Michigan State University, said:

“What appears in the owner’s manual is the best set of practices for operating a car if you want to get the longest life and the best performance out of it.”

Not making hard starts and stops and keeping tires properly inflated will increase mileage more than a fuel downgrade, according to Schock.


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Chicago Tribune

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