6 fuel-economy fantasies © Maksim Vivtsaruk/Shutterstock.com
6 fuel-economy fantasies

It’s a whole new game when it comes to fuel efficiency.

In August 2012, the Obama administration announced that it will increase fuel-economy standards to 54.5 mpg for cars and light-duty trucks by model-year 2025.

Because of high gas prices and a renewed drive toward fuel efficiency, drivers are looking to squeeze the most gas mileage out of their vehicles. But there are several long-held beliefs about fuel economy that can hinder their progress.

So Bankrate has tapped FuelEconomy.gov — the official U.S. government source for fuel-economy information — and talked to experts about some of the biggest fuel-economy myths. Knowing these widely held misconceptions can help you make fuel-economy choices that benefit you by saving you money.

“Better choices can save consumers hundreds, even thousands of dollars each year,” says Bob Boundy, a researcher with the National Transportation Research Center at Oak Ridge National Laboratory.

Here are the six most common fuel-economy myths.

Only small cars get good gas mileage

Only small cars get good gas mileage © Alistair Scott/Shutterstock.com

Myth: To get good fuel economy, you need a small car.

You don’t have to squeeze into a subcompact car to visit the pump less often. Although it seems logical, “The smaller car is not always the most energy-efficient,” Boundy says.

Size simply doesn’t matter as much anymore. Instead, Boundy says a lot of what makes a car fuel-efficient is under the hood, in the materials it’s made of or the way its body is designed.

For example, newer, standard-size vehicles have advanced technologies such as hybrid drivetrains, diesel engines, turbochargers and low-rolling resistance tires that allow them to compete on the fuel-efficiency charts, according to FuelEconomy.gov.

How to save: Compare the fuel economy of vehicles that meet all of your needs. You can save thousands of dollars over the life of the vehicle without compromising on size, performance, safety or quality, Boundy says.

Manual transmissions are better for saving gas

Manual transmissions are better for saving gas © AlexussK/Shutterstock.com

Myth: Manual transmissions are always superior to automatic transmissions when it comes to gas mileage.

“This has been true in the past, largely because automatics with five speeds were rare birds, indeed,” says Dan Edmunds, director of vehicle testing for Edmunds.com.

But manuals are no longer the definite rulers of fuel economy. “The gap has narrowed to the point where it’s often a toss-up, and the manual and automatic (Environmental Protection Agency) ratings are the same,” Edmunds says.

A lot of that has to do with advancements in automatic-transmission technology. For instance, automatic transmissions now have more gears. That cuts down on wasted fuel, Edmunds says.

And new classes of automatics — automatic manual transmissions, or AMTs — combine the best features of manuals and automatics, resulting in a potential 7 percent fuel-efficiency improvement, according to FuelEconomy.gov.

Edmunds says that AMTs bridge the gap between automatics and manuals.

How to save: Reign in your driving habits, and be smoother in your driving, Edmunds says. But also, keep convenience in mind. “You’re going to be driving this car for several years. Buy what you’ll be happy with,” Edmunds says.

Old vehicles gulp gas

Old vehicles gulp gas © Edler von Rabenstein/Shutterstock.com

Myth: Fuel economy decreases significantly as a vehicle ages.

Despite this common misconception, gas mileage generally continues to improve over the first several years of ownership during the break-in period — about the first 5,000 miles, according to FuelEconomy.gov.

“Barring normal wear of internal engine parts at very high mileage, there is no reason why a properly maintained engine won’t deliver the same fuel economy over its operating life,” says Tony Molla, spokesman for the National Institute for Automotive Service Excellence in Leesburg, Va.

The key phrase there is “properly maintained engine.”

Regular maintenance will keep your engine running at peak efficiency, Molla says. That means you should replace parts such as spark plugs before problems occur, he says.

How to save: “Regular maintenance is the best investment you can make to keep your vehicle running efficiently and reliably over the long term,” Molla says. And fixing serious problems such as a faulty oxygen sensor can improve your mileage by as much as 40 percent, according to FuelEconomy.gov.

Replacing air filters improves mpg

Replacing air filters improves mpg © sima/Shutterstock.com

Myth: Replacing an air filter on a modern engine will improve your fuel economy.

It used to be that replacing an air filter would give your fuel economy a kick in the right direction, and if your vehicle has an old engine with a carburetor, it still will.

But according to FuelEconomy.gov, that’s no longer the case with modern, fuel-injected engines. “The fuel-injected engine will deliver better fuel economy, lower emissions and, no matter how you measure it, better performance all the way around,” Molla says.

Today’s fuel-injected vehicle has an onboard computer that measures the mass of the air entering the engine and automatically adjusts the fuel flow accordingly, Molla says.

He says that’s why something such as a dirty air filter won’t have an appreciable effect on gas mileage. That doesn’t mean you shouldn’t replace your air filter.

According to a new study at Oak Ridge National Laboratory, replacing a clogged air filter on a fuel-injected, computer-controlled gas engine can improve acceleration time by approximately 6 percent to 11 percent.

How to save: Pay attention to the maintenance schedule in your owners manual. Some garages promote overly aggressive air-filter replacement schedules, which is an unnecessary cost, Boundy says. An air filter costs $10 to $15. If you add labor costs, it could boost the cost by $19 to $60, according to Edmunds.com.

Premium fuel gives your gas mileage a boost

Premium fuel gives your gas mileage a boost © the goatman/Shutterstock.com

Myth: Putting premium fuel in your vehicle, even when it doesn’t require it, will give your gas mileage a boost.

It may seem like premium fuel equates to better fuel economy, but you won’t see even the tiniest jump in your mpg by using premium fuel in a vehicle that’s designed for regular.

In fact, it’s just a waste of money, Molla says. Premium will cost you about 15 to 20 cents more per gallon, which can add up to $100 or more per year over time, according to the Federal Trade Commission.

In addition, “Using a higher-octane fuel than is recommended will have no effect on performance or fuel economy,” Molla says.

How to save: The FTC says that unless it’s recommended by your owners manual, don’t spend money on higher-octane gas.

Idling is better than restarting

Idling is better than restarting © Ministr-84/Shutterstock.com

Myth: Starting a vehicle uses more fuel than letting the engine idle.

In fact, an idling car is a fuel-wasting car. “Idling uses more fuel than stopping and restarting, and it’s not even close. That’s why stop-start technology is the coming thing,” says Edmunds.

Start-stop technology shuts off the engine when the vehicle is at rest — such as at a traffic light — and restarts it when the gas pedal is pushed.

The technology has become a staple on hybrid cars, Edmunds says. “It’s probably a fourth of their mpg magic, maybe more,” he says.

That doesn’t mean you should manually turn off your vehicle at stoplights — that’s an obvious safety issue, Edmunds says.

Also, normal starters without start-stop technology were only designed for a handful of starts a day, and ignition switches can wear out as well, he says.

How to save: If you’re going to be stopped for more than about five minutes, turn off the engine to save fuel, Molla says. He also advises avoiding jack-rabbit starts and sudden decelerations to save on fuel. “Drive like you have a raw egg under your right foot,” Molla says.

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