General Question

8lightminutesaway's avatar

Car questions?

Asked by 8lightminutesaway (1419points) June 22nd, 2008

Just curious…
Does starting a car use ~3 minutes worth of gas?
Whats more fuel efficient, driving at high or low rpm at the same speed? (different gears)
Does air conditioning actually use more gas?
Where can I find an oompa loompa?

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13 Answers

buster's avatar

Oomp Loompas are found in Willy Wonka’s Chocolate Factory. I think you find them in England.

Dog's avatar

Yes air conditioning uses more gas- especially while the car is at idle. Higher gears are always more gas efficient because they lower the rpms.

Legend has it that Oopma Loompas came from a remote island. Rumor has it that they are in a labor dispute with Wonka and can be found picketing the factory.

Wine3213's avatar

I’ve heard that driving at low rpm at the same speed is better. My old roommate use to do this all the time. He said it saved gas.

beast's avatar

Starting your car uses very little gas. If you’re planning on sitting there for a while, (over a minute) it is recommended that you turn off and then restart your car. It wastes more gas to run than to start.

It is better to drive in the middle of the proper gear. Driving to high or low in a gear could ruin the engine.

The Mythbusters actually proved that it is better and more fuel-efficient to use the AC, than to ride with the windows down. Aero-dynamics, my friend.

You can find Oompa Loompas in Oompa Loompa Land, as stated in the second Willy Wonka movie, Charlie and the Chocolate Factory.

Upward's avatar

Oompa Loompa – You can find them in their native home of Loompaland, which is a region of Loompa, a small isolated island situated in the Pacific Ocean.

XCNuse's avatar

Well hold on now guys, he didn’t say what type of car it was.

If it’s a fuel injected car, then starting it up won’t use much gas.
If it is not fuel injected but by carburetors, then yes it will use much more gas, so keeping it idling is better if you’re gone for less than 5 minutes

Think logical about your second question, is 6000 rotations a minute expel more energy than 2000 rotations?.... seriously?

To get the best mileage, if you’re on the highway, put your windows up and run the A/C on low unless it’s a cool day and you have a sunroof, then just open that up.
If you’re not on a highway and at slower speeds, keeping your windows down is far better.

vectorul's avatar

It doesn’t matter if you run the A/C on low or high. The A/C is based of of compressed gas, therefore the gas is always being compressed no matter what the little knob inside the car says.

JoeyDesignsStuff's avatar

One thing being ignored about the high-versus-low-rpm question is load. You can still use more gas going 50mph at 2000 than 50mph at 4000 if you’re flooring the pedal to get the car to move. You really don’t need to worry about this in automatics, since the car decides which gear it wants to be in, but in a manual, there is a point at which you’ll use more gas at a lower rpm because you’re opening the throttle so much. The amount of fuel injected into the system is based on throttle position, so flooring it at 1500rpm going up a hill is still extremely inefficient.

Basically, you want to be in the lowest comfortable gear you can be without feeling like you’re straining the motor. If your foot ever gets near the floor in normal driving conditions, downshift.

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SecondHandStoke's avatar

Short shifting (using taller gears) is more fuel efficient however there’s another way to think about it:

How much fun are you getting out of the fuel you bought?

If you have a car that obviously longs to be revved and comes alive above 4500 RPM why not do it?

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kritiper's avatar

A friend of mine mentioned that it didn’t matter if the RPM was high or low (reasonably speaking) but how much work the engine had to do. (With that in mind, a 5500 lb. Ford pick-up with a 2.6 liter V-6 engine will get the same MPG, relatively speaking, as 5500 lb. GMC with a 6.6 liter V-8.)
So I did an experiment using my 1956 Pontiac with a three speed manual transmission. After filling it with gas, I drove for a full week and always shifting into third gear whenever I could. The next week, after filling the tank, I drove for a full week, same places, same speeds, but left the car in second gear whenever I could, reasonably speaking. The result? No difference in gas mileage! The second week I actually got 1/10 of a mile per gallon better.
The A/C will lower your MPG some. The compressor will pull about ¼ horsepower from the engine.
Starting the car doesn’t take much gas and how much doesn’t matter if you want to drive the car.

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