Stick shift and gas mileage.

[iamtrout]

I was told by a friend of mine that cruising in 5th at 30 or 40 mph is bad for gas mileage because the engine has to work harder to keep up the speed. I was always under the impression that doing this would save on gas because it keeps the engine RPMs at a minimum.

Who's right?

 

[SouthPaW1227]

Im interested in knowing this as well

 

[fs5]

the amount of thottle you're giving the car has a lot to do with it also. If you're lugging the engine around at 30, then yes it's not only bad for the engine but you're using more gas

 

[iamtrout]

Well which is better for gas... cruising around at 40mph in 5th gear or 4th?

 

[BCYL]

If you try to accelerate while in 5th gear in slow speeds, the engine will have to work harder so will use more gas...

I believe to some degree ur friend is right

 

[iamtrout]

What if you're not accelerating? Or just gently accelerating?

 

[TheLonelyPhoenix]

Holding constant speed is always most efficient in the overdrive gear.

However, many owner's manuals will recommend against using overdrive until 40-45 mph, for the reason previously described - the engine has to work much harder to accelerate in 5th than it would in a lower gear. I usually don't shift into 5th until about 50 mph.

 

[BCYL]

Originally posted by: iamtrout
What if you're not accelerating? Or just gently accelerating?

Any acceleration you do will cause more work on the engine if you are in the highest gear

even trying to maintain your speed when you are going up a slight incline will use more gas compared to a lower gear

 

[ucdnam]

Think of driving a manual as like riding a bike. If you're cruising in the highest gear on a bike, it's the same as cruising at lower gears, you're not pedaling at all. The problem occurs if you have to accelerate. If you're in moving slowly and you're in the top gear, you're gonna have to apply a lot of force to get the bike moving, but if you're at the proper gear for your speed, it won't be as bad. Does that make sense?

 

[StageLeft]

Depends on RPM. I remember a 95 maxima manual saying not to stay below 2k.

 

[iamtrout]

Yah, good to know. Shift down to accelerate, even the slightest. 5th to cruise. So shift to 5th at 50mph sounds good? I've heard that 4th gear is called the "passing gear" on the highway but I pass people in 5th gear all the time. Is this ok?

 

[Electric Amish]

Originally posted by: iamtrout
Yah, good to know. Shift down to accelerate, even the slightest. 5th to cruise. So shift to 5th at 50mph sounds good? I've heard that 4th gear is called the "passing gear" on the highway but I pass people in 5th gear all the time. Is this ok?

Depends on how much you have to speed up.

If you have to accelerate too much you're just wasting gas.

 

[fs5]

Originally posted by: iamtrout
Yah, good to know. Shift down to accelerate, even the slightest. 5th to cruise. So shift to 5th at 50mph sounds good? I've heard that 4th gear is called the "passing gear" on the highway but I pass people in 5th gear all the time. Is this ok?

totally depends on your car, your speed at the time (and rpm) like I said previously, the amount of thottle you give the engine has a lot to do with it.

If you pass in 5th but have to stand on the gas to do it then it'd probably be better to down shift.

 

[Twista]

hmm *bookmarks*

 

[iamtrout]

My car's a Toyota Echo 2000 Coupe, one of those cars that gets 34mpg city / 38 mpg highway. God I wish the car came with a tachometer.

 

[Viperoni]

Originally posted by: ucdnam
Think of driving a manual as like riding a bike. If you're cruising in the highest gear on a bike, it's the same as cruising at lower gears, you're not pedaling at all. The problem occurs if you have to accelerate. If you're in moving slowly and you're in the top gear, you're gonna have to apply a lot of force to get the bike moving, but if you're at the proper gear for your speed, it won't be as bad. Does that make sense?

Not entirely true.

As in a bike, you have to overcome frictional and drag losses, which requiers you to put some effort into pedaling.

You can either use a higher gear and pedal less with more strength, or use a slightly lower gear and pedal a bit more using less strength.

Same thing for an engine.

My car doesn't like anything under ~1300rpm in 5th gear much, so I usually wait until I can cruise at at least 1600rpm. Will be higher for most other cars.

 

[LS20]

dont bog down the motor... additionally the car would require lots of throttle input to retain those low speeds at the tall gear... for the freeway thing, downshift.. itll make for a quicker pass. when cruising, just keep the motor at a tallest gear that is reasonable for the speed .. for my 2L car, that speed is 2000rpm...
in the end it doesnt make that much of a difference

 

[43st]

I use a Scangauge and I've watched fuel consumption very closely. What kills fuel economy is acceleration, period. The easier you accelerate the more efficient. When you're cruising at 65 you're actually gently pressing and releasing the gas pedal to maintain speed. The best case scenario for fuel efficiency is to idle the engine when you're coasting and gently accelerate when speeding up. If you're going 20MPH in fifth and stomp on the gas you're wasting a huge amount of fuel but you're not going to accelerate quickly. Better to be in 2nd or 3rd for that fuel usage.

 

[Viperoni]

Originally posted by: Thera
I use a Scangauge and I've watched fuel consumption very closely. What kills fuel economy is acceleration, period. The easier you accelerate the more efficient. When you're cruising at 65 you're actually gently pressing and releasing the gas pedal to maintain speed. The best case scenario for fuel efficiency is to idle the engine when you're coasting and gently accelerate when speeding up. If you're going 20MPH in fifth and stomp on the gas you're wasting a huge amount of fuel but you're not going to accelerate quickly. Better to be in 2nd or 3rd for that fuel usage.

The reason why fuel consumption goes up with engine load = acceleration = throttle amount is that more fuel needs to be pumped into the engine compared to lower load/acceleration/throttle.

 

[Ausm]

Best option is to leave it in fifth and never slow down!


Ausm

 

[Vic]

Don't "bog" the engine, especially when accelerating. It puts stress on the engine components and drivetrain and will shorten the life of your engine. In most gasoline engines, you want to stay above 2k rpms at all times while in gear, and go above 4k only occasionally (when needed for power). Anywhere within that 2k-4k rpm range is best for long engine life, and engines cost a lot more than the few ounces of gas you might otherwise save.
So yeah, shift up to cruise and shift down to accelerate, but still try to stay within that range at all times.

 

[MikeMike]

yea, basically dont get the engine below a certain RPM. if you try to accelerate and you feel the engine shimmy as you do, its time for a downshift.

MIKE

 

[psteng19]

I stay in the lowest possible gear that doesn't lug the engine.

 

[geckojohn]

Good call.

I can take my car on 3rd gear on the freeway... but it's way better for fuel economy to be at 5th gear.

 

[spidey07]

its bad for the motor and bad for your gas mileage.

More energy is required with that gearing. More energy = more gas used.