Saving on Gas Myths

Everyone's interested in saving money on gas. In fact, some people seem consumed by it (it's almost a daily conversation at my job -- who has the cheapest gas, what are prices up to now, etc.) As such, there are a ga-zillion suggestions for how to save money on gas -- but not all of them actually deliver savings. Consumer Reports lists four gas saving myths in its June issue. Their list includes:

• Morning fill-ups. A common tip is to buy gasoline in the morning, when the air is cool, rather than in the heat of the day. The theory is that the cooler gasoline will be denser, so you will get more for your money. But the temperature of the gasoline coming out of the fuel nozzle changes very little, if at all, during any 24-hour stretch. Any extra gas you get will be negligible.

• Air conditioning vs. opening windows. Some people advise you not to run the air conditioner because it puts more of a load on the engine, which can decrease fuel economy. But others say that opening the windows at highway speeds can affect gas mileage even more by disrupting the vehicle's aerodynamics. Our tests show that neither makes enough of a difference to worry about. Using air conditioning while driving at 65 mph reduced the Camry's gas mileage by about 1 mpg. The effect of opening the windows at 65 mph was not even measurable.

• A dirty air filter. Our tests show that driving with a dirty air filter no longer has any impact on fuel economy, as it did with older engines. That's because modern engines use computers to precisely control the air/fuel ratio, depending on the amount of air coming in through the filter. Reducing airflow causes the engine to automatically reduce the amount of fuel being used. Fuel economy didn't change, but the Camry accelerated much more slowly with a dirty filter.

CNN Money adds to these with the following ways NOT to save on gas:

• There have been additives, special magnets and even a pill that has promised to improve a car's fuel efficiency by as much as 30 percent in some cases. While the promise of stretching your gas dollars seems awfully lucrative, especially when they cost under $20, most of these products provide a negligible, if any, improvement in fuel efficiency, said Rik Paul, the automotive editor for the publication Consumer Reports. Consumer Reports and the government's Environmental Protection Agency, have tested dozens of these products finding that none of them offer any significant improvement in fuel economy. (click here for Consumer Reports' detailed reviews on some of the supposed gas savers)

• Some drivers insist the best time to buy gasoline is on a Wednesday, when pump prices have cooled from the weekend run-up when oil companies typically raise prices. That's true to a point, says Tom Kloza, chief oil analyst at the Oil Price Information Service. Gas prices tend to be higher on the weekend, but there's no ideal day of the week to purchase your gas.

• It's probably a myth that goes back to the days when cars were equipped with carburetors, but many drivers believe that starting up and turning off your car repeatedly is a fast way to drain your gas tank. But because of modern fuel-injection technology, drivers actually save gas by turning off their engine than letting their car needlessly idle, says Consumer Reports' Paul. Granted it's probably not sensible shutting down the engine every time you get stuck in traffic, but if it looks like you might be at the drive-thru for more than 30 seconds to a minute, it's worth turning off your car, says Paul.

And then CNN lists a few ways that you CAN save money on gas. I've highlighted several of these recently, so now I'm just going to list the ones I haven't covered in the past couple months:

• Removing excess weight from your car can also help save you gas. The Department of Energy estimates that drivers can save anywhere between 3 and 6 cents a gallon (assuming gas prices of $2.97 a gallon) just by removing those golf clubs and other unnecessary weight from your trunk.

• If your car comes equipped with cruise control, make sure you use it, especially on long trips. Edmunds.com's study revealed that using cruise control at highway speeds offered an average fuel economy savings of 7 percent.

Anyone else have some ideas that either do or don't work?

Comments

[Kevin]

I've actually read the opposite about cruise control - especially on hilly or curvy roads. The throttle seems to jump up and down so much it isn't as big a saver as keeping the accelerator constant with your foot.

[Rzrshrp]

Kevin: I've read that THE ONLY time that cruise control doesn't help mileage is on especially hilly roads. I guess if you're one of the puls and glide supermilers, that's better than cruise control too. Every source I've read says that on generally level open highways, cruise control is usually best for mileage because you don't have the tiny bits of surging that a human driver would do.

[Rzrshrp]

Oh, and normal sensible driving always applies:
Try to keep constant speed.

Don't drag rice from stop light to stop light.

Let your car coast up to a red light instead of accelerating up to it just to throw on your brakes.

Keep tires inflated properly.

Do errands at one time because a warm engine is more efficient than a cool one.

Don't bother with higher octane unless your manufacturer requires it.
On that note, don't get a car that requires higher octane fuel.

[rwh]

I mentioned this on another post last week, but I noticed I get between 5 and 10% better gas mileage by using the straight 87 octane gasoline instead of the 87 octane 10% ethanol. Where I live the ethanol is subsidized 10 cents a gallon. That doesn't make up for the decrease in mileage, and the higher the price of gas, the more ethanol costs compared to straight gas in real terms.

Slowing down helps a lot. I drove over 500 miles this weekend and kept the interstate speed at 66 (70 speed limit) and the two lane speed at 60 (55 speed limit). I got 41 mpg in my Honda Civic.

[K]

Quit the stop-and-go mentality. I love people who gun up to the speed limit only to hit the brake 100 feet later because of a light or a bend. Coast more, gun less. Unless you drive a hybrid with regenerative brakes, every braking is literally wasted gas. (Not to mention additional wear on your brakes.)

[Shane]

rwh is right on...you'd be amazed at how much you can save by slowing down. My average gas mileage has gone from 21 to 25 just by going about 65 on the freeway instead of 75. There's a nifty calculator at http://www.slowdowntosavegas.com/

[Financial Goal]

I have also seen how my mileage has increased as I have been slowing on the freeway. You still see many cars zipping by you but that is ok with me. Once we hit traffic in Los Angeles, we'll all arrive around the same time anyways. =)

[Cincinnati Retirement Planning]

I only follow two methods on saving gas. Driving slow And not turning the air condition.

[JK]

Check out the insane mileage you could get by hypermiling...

www.cleanmpg.com

Remember what they did in 1974 during the oil crisis? (I wasn't alive, so I don't remember, but I read about it!) Enacted a federal law mandating speed limits of 55!

It's common sense! Something there's very little of in Washington now...

[Margo]

If you're overweight, you could save on gas by hitting the gym. 25 pounds extra in the car hurts your mileage the same, whether it's from excess junk in the trunk, or, excess junk in YOUR trunk.

[gasPal]

I enjoy the forum's comments, and I would like to add, claims that “human release of greenhouse gases is damaging our climate.” I think these claims have merit. Well how can we help reduce green house gases. One way is to release cleaner emissions into the atmosphere. Just think if you only needed gasoline and water to run your present auto. Will save on gas & cleaner emissions for the environment, with new water
power technology ITS EASIER THAN YOU THINK.