thanh27

iTrader: (12)

Copy/pasted straight from Yahoo:

4 gas-saving myths
Tuesday May 15, 3:34 pm ET

By David Ellis, CNNMoney.com staff writer



Using a special additive or cutting off your A/C won't really cut your gasoline consumption. But myths like these run rampant in the minds of American drivers.
Right now, the price of gasoline is again setting record highs. The average price for a gallon of regular hit $3.087 Tuesday, the third record in a row.


So before you attempt a half-baked scheme to stretch your gas dollars, here's a look at what's fact and what's fiction when it comes to fuel economy:

Nothing but gimmicks

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.

"With all the pressure car companies are under, if one of these inexpensive devices dramatically did improve fuel economy, they (automakers) would be all over it," said Paul.

Windows, air conditioning - who cares?

There's the old saw that leaving your windows rolled down creates an aerodynamic drag on your car, cutting down on fuel efficiency. And there's the notion that the fastest way to drain your gas tank is by running your air conditioning.

Don't believe either one.

In two separate studies conducted in 2005, the automotive Web site Edmunds.com and Consumer Reports compared the fuel economy of both a sedan and an SUV at highway speeds with and without air conditioning and how open windows affected gas usage.

What they found was no significant difference in fuel economy in either sedan or SUV under either condition.

Don't wait until Wednesday

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.

Geoff Sundstrom of the motorist organization AAA notes that gas prices fluctuate from day to day and are determined by gas station owners who look at a variety of factors including wholesale gasoline prices, competitors' prices and food and drink sales if they have an attached convenience store.

Drivers who want to bargain-hunt for inexpensive gas should instead check out Web sites like Gasbuddy.com, which allows consumers to find the cheapest gas in their area simply by entering their zip code.

Restart your engines

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.

Tips you can use

So what are some fuel-savings tips you can trust?

Make sure your tires are properly inflated for starters. Besides posing a safety hazard, underinflated tires can reduce your fuel economy slightly, based on Edmunds.com's 2005 study.

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.

But the biggest fuel saver is driving the speed limit and driving sensibly. Rapid starts and stops and exceeding the speed limit will dent your pocketbook. Just by adhering to one of those, the Department of Energy estimates that drivers can save anywhere between 15 and 98 cents a gallon, again assuming pump prices are at $2.97 a gallon.

philude

iTrader: (19)

nice, Mythbusters did the windows vs. A/C one and had the same results. thanks for the info!

ekim1

good read, thanks for the information. I figured that AC and windows wasn't that big of a deal. I feel like it takes a lot more effort fo smaller motors to have the A/C on all the time. Seems like A/C doesn't bother the VQ35 too much. At least for me it's always 20-21 MPG with A/C on 24/7 practically.

Phantom Menace

iTrader: (4)

Thanks for the heads-up. I love my A/C.

How about this:

Ztalker

didn't mythbuster also did the tailgate Up/down test? driving a pickup truck with the tailgate up position is actually more aerodynamic.

trains1937

Very well organized and informative post.

hardrock905

Yes they did. If I remember correctly, when the tailgate was up the truck got better fuel economy. Surprising.

hardrock905

I just added gasbuddy.com to my favorites.

Motormouth

iTrader: (44)

I also remember car & Driver testing out the open window / ac thing and they found a difference. it is rediculous to think it has no bearing when a .1 cd of drag is searched for by car designers and a low drag co is given as a reason for better gas mileage.

Ztalker

i wonder why most pickup drivers are still driving with their tailgates down....thinking they are saving gas?

hardrock905

There are differences, but like the article said, "What they found was no significant difference in fuel economy".
Also, windows up: More aerodynamic but A/C running hurting mpg.
Windows down, Less aerodynamic but A/C not affecting mpg.
I guess on some level, the trade-offs of windows up -vs- windows down come close to evening each other out?

Ed 718

iTrader: (32)

No fat chicks in the Z or my gas mileage will suffer............

thanh27

iTrader: (12)

hardrock905

I imagine the better mpg myth is widely believed. I thought the tailgate down option would get better mileage as well. I was quite surprised, as was the Mythbusters cast, of the results.
And hey, some people are a little behind on the news, as usual.

Playboy's Z

didnt know about the ac one thanks man

OCZTrack

iTrader: (1)

They came to the conclusion that engineers have designed the bed of a truck to create a vortex of air around the bed and thus making it more aerodynamic. By leaving the tailgate down they are in turn not allowing that vortex to form and lowering their MPG.

iknowitsfast

iTrader: (1)

Thanx! This is great info.....and yes, i will admit I am a victim of the windows down, and the A/C myth! ughh thanx again

I1DER

The article is a good example how people will grab on to something without looking for the devil in the details. That article has been reprinted on many sites because it seemingly flies in the face of many accepted notions. It was written for the average simps, who are determined to have their cake and eat it too.

It said that if you have to roll down the windows(lose drag efficiency) to cool off, you will loose no more efficiency than lost by running the AC. Basically it should have said that if you want to be comfortable, it will cost you. It should have added that their principle only applies at high speeds and with modern air conditioners, but they dropped off that part.

The main reason for aerodynamic designs is to decrease drag and raise fuel economy. Having the windows down ruins the aerodynamic benefits(especially in sleek small cars) as speeds go up. At slow speeds(less than 40?) the effects aren't nearly as harsh on mileage as they are at high speeds.

Air conditioning draws power. Granted that new systems are way more efficient than older ones, there is still a draw. In my '93 Pathfinder you can hear/feel the draw on the engine when I turn the AC on. In the Z, I don't notice it, but it is there.

The article didn't explain that both Edmunds.com and Consumer Reports have also stated the above. The tests didn't negate the known. They simply indicated that at higher speeds in 'either or situations', removing the pull from the AC is usually countered by the increase in "windows down" drag. At lower speeds, Edmunds recommends opening windows and turning off AC for fuel economy.

The best for fuel economy as shown in another test http://www.bankrate.com/brm/news/auto/20050804a1.asp illustrates that the most fuel efficient way is to pay attention to both factors(of course) and don't use AC nor have windows down. You could just have your wife/gf give you a cold sponge bath while driving in the heat.

00MaxSE

iTrader: (3)

Wow, yeah my brother told me about that episode. It's hard to believe that.

Armitage

iTrader: (15)

Good news. I love my windows down.