Which one wastes more gas? Higher or lower RPM's?

Question

My husband and I had a bit of a disagreement last night.

My dad taught me (when I was learning to drive stick shift, years ago) that I would use up less gas if I didn't keep the car constantly at higher RPM's... Therefore, if I'm cruising (not in a rush/hurry) I stay in the highest possible gear (2k-3k RPM's)

My husband, as always being contrary, says that the car actually wastes LESS gas when in higher RPM's, so whenever he drives, he likes "listening" to the roar of the engine, by keeping it in a lower gear than I would (usually goes no higher than 3rd or 4th gear, when I would already have been on 4th or 5th)

What he says doesn't make any sense to me, but I'm just a girl, so what the heck do I know about cars, anyways, right?

Could an unbiased party help us solve this debate?

Thanks...

Oh, and If I'm wrong, would you be kind enough to explain why/how to the best of your abilities...

I'm a very gracious loser, as long as I am shown why I lost...

Thanks!

Answer 1

Your husband is so wrong, and you are correct. Lower rpms saves gas. But don't let the rpms get too low, so that the engine is lugging. Then you will be using more fuel.

Answer 2

You are correct mam,  lower rpms more efficient.  The only reasons to run a bit higher rpm is under a heavy load to prevent lugging the engine.  

Answer 3

Ok, here is both sides.

As already said above by others, spinning the motor uses MORE fuel. Think of it this way; how do you make an engine increase speed? You add more fuel to it. So running a motor at a lower rpm will cause it to use less fuel for the same amount of load.

Your husband is on to something though... He is most likely running the motor higher in the power band, so the motor is more efficient. So what this means is that the motor is getting the most amount of power from the amount of fuel that is being consumed. On most vehicles, this will be somewhere near the mid range of the motor's capable operating speed, but is not always the case and every motor is different.

So, your husband is making the most power for the amount of fuel being used.... BUT YOUR GETTING THE BETTER FUEL ECONOMY!!!

Answer 4

IT takes less energy to walk a mile than it does to jog a mile and less energy to jog a mile than to run all out for a mile. The same principle applies to a car engine. At idle the tach, depending on the car, will read around 700RPM. To get the engine to 3,000RPM you have to depress the accelerator. In other words feed the engine more gas. The faster the engine turns the more energy required and that energy is the gas it burns. The higher the RPM's, at a particular speed, the more gas the engine burns. If your husband can't understand that then you'll just have to live with the realization that he "ain't the sharpest tool in the shed". LOL

Answer 5

higher rounds per minute burn more gas.  on a 4 cyl engine if the rpms are at 2000 that means that your engine fired at 4X2000 or 8000 times at 1000 rpm's 4000 times less gas.  Your dad is smarter than your husband.  good luck  

Answer 6

Take your husbands " Man license " away and give it back when he learns operate your car efficiently

Answer 7

Higher RPM's uses more gas.  

Too low of RPM's or lugging the engine, might make it ping (pre-detonation), & is hard on the engine.  Look for a happy medium.