6 Gas-Saving Myths

With gasoline prices hitting record levels, it seems everyone has a tip on how to save fuel. Much of the advice is well-intentioned, but in the end, much of it won't lower your gas bill.

Read the whole story here.

Comments

[Herrington]

Actually, the cost disparity between regular unleaded and the higher grades has not changed in proportion ot the increase in cost per gallon. So at $4 per gallon, the two extra miles per gallon on the highway you get from a higher octane fuel may result in a free gallon per tankfull.

Check it out. Fill up a 20 gallon tank with 89 octane and get two more mpg highway, depending on your car. 40 extra miles per tankfull.

Much depends on your car's computer control system. With a thourougly modern system, higher octane will allow it to advance spark timing and boost horsepower per unit of fuel. And the physics is that more horsepower per unit of fuel will get you further on same unit.

It did not make sense to buy mid grade when when gas was $2 a gallon and there was a 10 cent per gallon cost. But at $4, the math works.

[sparkey]

I have a 1990 ford festiva with 300,000 miles on it and it still gets 45 MPG. It smokes a little, but with another engine only costing $1800,00, it'll be just as good as a new car with twice the gas mileage.

[UnbiasView]

No, it's not just as good as a new car. Every time you fill up with gas that car doubles in value . . . is there still an 8-Track in there?

[chinacatsunflower]

8-track? 1990?

[ReasonIsMyReligion]

7) Putting a "Support the Troops" sticker on your SUV will absolve you from your lousy gas mileage.

[CountryBeforeParty]

#6 in the list, I believe, was referring to the product CA40. I have heard Ed Schultz promoting it, and it seems that this fuel additive works, and is now being sold to some larger trucking companies, and the military.

The author is being a bit naive to suggest that if there were a better way to get more gas mileage out of the fuel, the oil companies would do it.

Excuse me? Since when have the oil companies been interested in the public good? If we didn't have regulations and mandates we would still be using leaded gasoline.

[JudgeCrater]

No mention of running your car on water? I'm sure that the Internet can't be lying to me regarding that idea, can it?

[KillTheMessenger]

Get a hybrid. Instant 45-48mpg. 8%+ annual return on investment. A total no-brainer.

[Photofarm]

Actually, Hybrids are better for stop and go, or city traffic. If you drive on open highways in rural areas, not near the improvement in mileage. Did you add the cost of the replacement batteries? Another major expense, and makes the economic issue more of a toss up than a no-brainer.

[KillTheMessenger]

Sorry! Of course, I meant to say $6/gallon gas before 2010! My bad.

[KillTheMessenger]

We drove the car in all kinds of conditions. The difference in consumption was about walking distance per gallon. But then, we don't drive above legal speed limit and usually slower. What replacement batteries? I don't intend to keep the car beyond the manufacturers guarantee and there is little evidence that the batteries wear out and need to be replaced, anyway. That's one of those urban legends out there that just does not seem to die, no matter how much evidence refutes it.

Anyway, if you don't like it, leave it. Let's see how you will fare financially with $6/gallon before 2011.

[ReasonIsMyReligion]

Whoa. Depends on how many miles a year you drive and incremental cost of hybrid over regular engine. Cheers.

Some-brainer.

[KillTheMessenger]

Assuming average utilization of 15,000 miles a year and switch from a 7 year old car with slightly over 20mpg. Which would be very typical for many American households.

You don't have to get a hybrid to break more than even. One could probably get >10% ROI with a small car like a Yaris, assuming good driving habits because of the lower cost (about half as much as a hybrid).

[Rule Of Law]

"Don't you think oil and car companies aren't doing everything they can to beat their competitors?"

Uh, no?

[FrictionSoul]

Cold gas IS denser, never mind what Consumer Reports says. I get better mileage in winter. Curiously they left out that fact that having a full tank of gas works very well for SUVs in summer. Reason: less room for vapor.

Don't believe me? Then why does your gas cap have a pop to it in summer, but not winter?. Try it. The less gas in your tank, the stronger the pop.

[ReasonIsMyReligion]

Oy.

If anything... better mileage in cold due to AIR being denser, therefore more air-fuel mixture per "mouthful" in piston cycle, therefore more power per RPM, etc. If anything.

Gas cap pops due to temp of air/fuel vapor mixture. Hot gases expand, etc.

[drumz]

The less gas in the tank the less weight and therefore better mileage

[ReasonIsMyReligion]

True.
All four seasons.

[Photofarm]

Actually you get better mileage in the summer. At least that is the way it is in real winter country.

The less gas in the tank the more vapors, doesn't matter what the temperature is outside.

[Tom95134]

Pump up your tires.

While the article poo-pooed this it does effect your mileage. However, gas guzzling SUV s will never see it. High mileage cars should consider running your tires slightly... SLIGHTLY over inflated. Recommended tire pressures are a combination of various factors the most important of which (to the manufacturer of the car) may be ride. Buy a good digital tire gauge and check your tires weekly first thing in the morning. Look at the maximum inflation pressure on the tire sidewall and then raise the pressure somewhat higher (2~3 lbs) than the sticker pressure while maintaining the proper front to back differential. Tire wear generally will not be affected because most sticker recommendations under inflate the tires. In fact your tires may last a little longer because they will not wear at the shoulders. The contact patch does not change that much but if you are in an area where you have a lot of rain you might consider a better tire than the ones that came on the car. Rotate your tires regularly. When you rotate your tires take a close look at the way they are wearing. (Think about buying an inexpensive tire tread depth gauge and measuring the tread depth across the tire.) Consider low rolling resistance rated tires.

If you regularly have a full load of people (or cargo) make sure your tires are set above recommended pressure. Get rid of all that junk in the trunk, it's costing you gas.

[Paul]

#1 gas saving tip: use public transit

[ReasonIsMyReligion]

Right on.

#1A -- Get a bike.

After you burn off 10 pounds, when you DO sit your a** back in that car, that's less weight to haul.

[KBAR]

#10. Put 4 fat asses in a car not just 1.
#9. Don't drink and drive. Just drink and STAY home!

[Podewumun]

Glory be! That's the only intelligent thing you've ever posted, KBAR.

[dadw5boys]

Take all the junk off cars and make them weight less so we can save fuel.

I am amazed at people driving the "SHOW TRUCKS" 4 wheel drives who don't have a farm, never go off road or ever put anything more than grocerys in the truck.
The tires and wheels alone on those trucks and LARGE SUV's weigh 150 to 200 lbs each and it takes a lot of gas to puch 800 lbs down the road.

Filling your tank so your not making a lot of trips just to buy gas.

Driving over 55 miles an hour cost 1.5% more per mile because of the increased air resistance.

I take one of the folding bicycles then park the car and ride around to the stores. The streets are not friendly to bicycles and the cops raise hell about riding in the sidewalks even if there is no one ever uses the sidewalks.

[RTIII]

While it's true that driving slower USUALLY saves fuel, this statement:

"Driving over 55 miles an hour cost 1.5% more per mile because of the increased air resistance."

is useless and, in short, is clearly wrong.

The above statement suggests a linear relationship. In fact, aerodynamic resistance rises with the square of the speed - double the speed, square the resistance. So, there is no single % change that's true "per mile".

Secondly, a vehicle's gearing and engine power-band play enormous roles. Internal combustion engines typically have saddle shaped fuel performance curves. (Plot fuel versus efficiency on a two dimensional grid and it makes a gentle "U" shape.) At the lowest and highest running speeds (RPM), efficiency is lower (higher fuel consumption), and in the mid-range, fuel consumption is lower. Then, factoring in where an engine makes its peak torque and peak RPM helps one find the most efficient running circumstances.

This means that for each gear a non-electric automobile has, there will be a sweet-spot range where efficiency is best. Generally, being in the highest gear and in the sweet-spot yields the best MPG.

END PART I

[RTIII]

PART II

I recently experienced this first hand as I took a trip across the US a couple of weeks ago. I had a vehicle (a camper) that I was going to drive some 5 thousand miles round-trip which I had just bought. With its existing engine (a "hot rodded" VW engine), at best it got 9 MPG, while NOT towing, and I intended to tow a trailer. Finding that unacceptable, I installed a different engine (a Porsche 912 engine), one that got 17MPG city and about 22 highway in a similar vehicle I already owned. I did the swap and also included a matched transmission. I then carefully observed fuel economy. MUCH TO MY GREAT SURPRISE, the best mileage of my entire trip was doing 80 MPH across west Texas! (20 MPG) The reason for this was that at that speed the vehicle was in the sweet spot of the engine's power band, between peak torque and peak horsepower, so it got a lot of miles covered for what fuel it burned...

[WIpatriot]

What, no coverage on the magnets on your gas line and waxing for less wind drag?

[ReasonIsMyReligion]

ROFL.

How about a magnet on your front bumper to suck you along (so to speak) vis-a-vis the car in front of you?

[robinhood2]

Too bad our daily newspapers run full page ads for those "gas saving devices". I guess anything goes when it comes to going after ad dollars.

[WIpatriot]

Remember the pellets in your gas tank? Or the new "Tornado" devices that are supposed to create better air-fuel mix and increase mileage?