Gas-saving tips: Fact and fiction

With gas prices rising above $3.60 a gallon, drivers are wondering if there's anything they can do to improve gas mileage.

``Money" Magazine has exposed several myths, and News/Talk 92-3 KTAR's Bob McClay took the list to two automotive experts in the Valley to get their take.

Myth No. 1: Using premium gas will get you more miles to the tank-full.

Linda Gorman of AAA Arizona says, ``Don't use premium. The lowest octane will do just fine. You're not going to get any better gas mileage out of premium fuel."

Mark Salem, host of 92-3's ``Under the Hood" agrees.

``It is a myth. If you were to get one mile to the gallon more, the difference between cheap and super compounds that mathematical equation something terrible, and you're never going to make progress."

Myth No. 2: Turning off your air conditioning saves gas.

Gorman says that's been a conventional wisdom, ``but it really makes very little difference."

Salem says that applies only to cars built before 2000.

``The air conditioning unit was larger than a loaf of break. It took a lot of horsepower to turn that compressor," he says, adding that in newer cars, you can run the air conditioning all you want and it won't affect your gas use.

Myth No. 3: Using a gasoline additive can improve mileage.

Forget it, says Gorman. ``Let's face it. If there was something out there that improved fuel economy that much, they wouldn't be able to keep it on the shelf."

Salem chimes in, ``All of this stuff does nothing more than take hard-earned money out of your pocket and put it in theirs. You're not going to get anything for it. We have tested this stuff inside and out."

Myth No. 4: Filling your tank in the morning when it's cooler saves gas.

Probably a little, Gorman and Salem agree.

``We recommend filling up at the coolest part of the day," says Gorman. ``Now, how much extra gas you're going to get -- probably pennies."

Salem says, ``If you're going to waste your time doing this, the net gain at the end of the year might be a nickel. So, the question is, do you want to set your whole schedule up to save a nickel?"

Myth No. 5: A dirty air filter will lower your mileage.

Gorman says, ``It's good for car maintenance to keep your air filter clean, but a dirty air filter really isn't going to have that much impact on fuel economy."

And, Salem: ``It's no different than us. If I take a big piece of duct tape and wrap it around your lips and your nose, you're going to have a tough time inhaling air. The idea with your car is when you tape its mouth shut with a dirty air cleaner, it's having a tough time breathing, it's going to use more fuel."

Myth No. 6: Over-inflated tires can provide better gas mileage.

``You don't want to over-inflate, that's not going to help your fuel economy," Gorman says, ``but under-inflating will actually lessen your fuel economy."

Salem couldn't agree more. ``If you want to see how much fuel economy you're going to lose, just go flatten four times and tell me it doesn't make a difference. The motor's going to work hard to carry that big, heavy, 35-hundred pound car down the road with four flat tires."

Salem says to follow the manufacturer's specifications on tire air pressure. You can find that on the side of the tire.

One more recommendation for saving gas: Slow down and avoid fast starts. • Gas-Saving Myths