Ways to improve gas mileage--keep windows closed??

[inflames988]

I was checking out some of these methods--for obvious reasons. This one totally threw me off--

Keep your windows closed when possible. Open windows actually reduce gas mileage compared to using the A/C.

Are they serious? the only way i can see this being true is that it makes the car less aerodynamic. I prefer winows to A/C and always thought windows are better for gas.

I could see this being a problem more at high speeds?

Any other ways besides the usual (no a/c, keep engine tuned, spark plugs, drive around 55mph on highways and not faster)

The windows thing was what really threw me off. Gas is gona kill me this year. Going to school 5 days/week means filling my 16 gallon tank EVERY week. Even if prices go down it will still be $40+, somewhere around $10 just to get there and back each day.

[Jaggannath]

It's true... below a certain speed an open window is better, above it AC is more efficient. However, realistically the increases in efficiency are so miniscule as to be unreasonable, do what makes you happy

[als814]

They did a test on myth busters to check this out. They noticed at 40 miles an hour, it was more efficient to have the windows open, but I think if you are on the highway going like 60 or above, it would probably be more efficient to use AC.

[inflames988]

well if thats the case then windows will still be much more efficient for me. Usually dont drive highways much anyway, and tend to stay very close to the speed limit as thats usually the best mileage wise. So either way though, its better to use neither a/c nor windows? what about heating during winter?

[peekaboo]

drive a small (japanese) car and don't drive like a maniac.

[Jaggannath]

Originally Posted by peekaboo drive a small (japanese) car and don't drive like a maniac.

A little off topic, but hey, why not?!
And heating is drawn straight from the engine, so it doesn't really cost you anything more than the normal running cost of the car to do. Go windows down when it feels right

[inflames988]

Well for summer..windows are my bes bet. the rest of the time i wont really use anything. maybe heat in winter.

[Panama Red]

Myth busters or not, I've done my own tests and it is true - and more comfortable with the A/C on. The new style AC units aren't like the old HP robbing units of days gone by. Sure they still require some HP from the engine but the loss is negligible. I've also run a test on a pickup truck. An open bed with the tail gate up uses more gas than one with the tail gate down and the best gas mileage configuration is windows up, A/C on and a flat bed cover w/tailgate up.

[Markoman01027]

Removing excess weight also helps with gas mileage.

[Panama Red]

Originally Posted by Markoman01027 Removing excess weight also helps with gas mileage.

Yup, gives me good reason to not drive my mother-in-law anywhere!

[Byte 2.0]

One that is often over looked is having the correct Tire pressure. Low pressure is less effecient and wears out your tires faster, more fiction on the road surface.

Over inflated will cause a bad wear pattern on your tires as well.

[bailey]

mich gov put a price cap on gas of $2.99 a gal yesterday

[David M]

The percentage difference in preserving the cars laminar flow versus running the air conditioner is probably such a small difference that its not even worth considering. It's probably less than a 5% difference I would guess.

[Markoman01027]

Originally Posted by Panama Red Yup, gives me good reason to not drive my mother-in-law anywhere!

LMAO

[inflames988]

How can the govt put a price cap on gas like that? wouldnt mine that here. jumped from 2.99 yesterday to a MINIMUM of 3.25 today...seriously here its rediculous.

[rspassey]

1.99 pesos(around 3 pesos/ usd) per liter here in Argentina. Doesn't matter to me, I don't drive. But a lot of the drivers we use here dont use nafta, they use the 'gas' which is like 15 pesos to fill a 200 liter tank. I think thats the solution, you have to fill up more, but its a lot cheaper.

[thefultonhow]

Some tips only apply to those with manual transmissions:

• Stay in gear while braking for a stop sign or light. You will actually use less gas than if you put in the clutch and idle up to the stop.
• I've noticed that 4000 rpm is the magical point at which gas mileage gets appreciably worse. Try to stay below that (in a manual or automatic car). Shifting at 3000 or lower is even better in most conditions (i.e. when not going up a hill).
• You might think you'll use less gas at lower RPMs, and thus you should shift early; however, if you're in fifth and you need to go up a hill, you'll actually use less gas by downshifting than by flooring it.

[edfair]

Red,
I don't know what part of the government did the test, but a report came out last year saying tailgate up was more efficient.
Something like a circulating bubble within the bed giving smoother airflow over the cab and gate.
I don't know if there were exceptions. It isn't important to me since I have a cover.
I normally would trust your tests, but whoever did the tests seemed pretty positive.

[Jaggannath]

Originally Posted by Panama Red Yup, gives me good reason to not drive my mother-in-law anywhere!

hehehe you'd better watch it PR, thar be dragons

Originally Posted by David M The percentage difference in preserving the cars laminar flow versus running the air conditioner is probably such a small difference that its not even worth considering. It's probably less than a 5% difference I would guess.

Yeah, that's exactly what I said... at the end of the day it's a predominately academic question.

And edfair, I'm not sure what to think of that. Potentially, the circulating air in the tray could cause upward pressure which causes the car to appear more streamlined, but equally free flow from the cab down into the tray and out the back could be more efficient.

[bailey]

the govoner called the marithon oil company and asked them to do it and they agreed to do it, I have yet to see it though, it was announced on the tv news here.

[Hi Ho]

I don't think the miniscule difference in gas milage is worth fretting over. I prefer A/C to the windows. In fact, I can't stand having the windows open. It drives me absolutely nuts!

I drove down to Death Valley a couple years ago in my 95 Civic. We had the A/C on most of the time and averaged 40 MPG.

[blue60007]

Originally Posted by Hi Ho I don't think the miniscule difference in gas milage is worth fretting over. I prefer A/C to the windows. In fact, I can't stand having the windows open. It drives me absolutely nuts! I drove down to Death Valley a couple years ago in my 95 Civic. We had the A/C on most of the time and averaged 40 MPG.

Agreed. Don't worry about getting .01 more MPG's out of your car.

[mattg2k4]

I don't know about the rest of the gas-saving techniques, but here's how I keep my car cool:

When I'm just starting to drive, I'm in a parking lot or slow residential streets usually, so I roll all the windows down for a minute or so, which gets rid of a lot of the hot air in the car from sitting in the sun. Then I roll them back up and turn on the A/C when I get onto the faster roads or highways.

I also turn the A/C off about 30 seconds to a minute before I reach my destination. It will save a tiny bit of energy, and because the A/C stays cold for a bit, the car stays cool. I've heard that it also reduces condensation inside the A/C.

[Hi Ho]

Actually the best way to cool off the car is to keep the windows up, turn the A/C on, and switch to recirculate. Opening the windows is the most inefficient way to cool it down, especially when it's hot outside.

[mattg2k4]

Opening the windows is very efficient when the car is significantly hotter inside than outside, no matter if it's hot outside. A few light breezes and the air inside your car is already several degrees cooler. Granted, it takes more than a few light breezes to cool down the non-air parts of the car, but it makes the car pleasantly cooler much faster than any but the most powerful A/C could.

[Hi Ho]

In my Civic I do what I said above and in 20 seconds the temperature is comfortably cool.

[thefultonhow]

Originally Posted by Hi Ho Actually the best way to cool off the car is to keep the windows up, turn the A/C on, and switch to recirculate. Opening the windows is the most inefficient way to cool it down, especially when it's hot outside.

Whenever I use the AC, it's always on recirc. I find that not only is it more efficient, but I avoid the smell when I'm behind a beater.

[Hi Ho]

^ I like fresh air.

[thefultonhow]

Originally Posted by Hi Ho ^ I like fresh air.

I think it helps that you live in a rural area. When I'm sitting stuck in traffic on the Beltway, believe me, it's best to leave it on recirc.

[Jaggannath]

With always running your AC, you need to make sure about 1 min before stopping your car and switching off that you've switched off the AC, to ensure that you stop water pooling in the condensor, which can be bad for not only car smell but also your health