Does going into Neutral on an automatic save gas?

  • Thread starter Thread starter Dougboy
  • 24 comments
  • 1,516 views
Dougboy

Dougboy

Messages
1,654
Messages
dougboyy
Hi guys

Ive been trying to drive economically for a while now. I drive an automatic and i would pop the transmission into neutral at red lights. Does that save gas or is it just a misconception?

Also, would popping it into neutral while coasting damage the transmission in anyway? I know manual drivers do that.

Thanks
 
I dont thing it would do anything. While your coasting to the traffic lights or whatever and your foot is off the gas and your in gear its the momentum of the wheels turning the engine above the idle RPM not the throttle keeping it above the idle RPM. So I dont think it would do anything. If it did though I assume it would make a minimal difference to your fuel consumption
 
Don't pop it into neutral until you're at a full stop. And don't do it unless you'll be stopped more than half a minute.

Yes, it will save gas, but it isn't a very significant factor.
 
If you're going to be stopped more than half a minute, why not just put it in park?
 
No matter what transmission you use, don't bother putting it into neutral while moving in an attempt to save gas. As Slick Rick said, when you're coasting the wheels are turning the engine, not the other way around.

Most, if not all modern cars cut the fuel when coasting. Idling in neutral, on the other hand, requires fuel to keep the engine turning.
 
Wolfe
No matter what transmission you use, don't bother putting it into neutral while moving in an attempt to save gas. As Slick Rick said, when you're coasting the wheels are turning the engine, not the other way around.

Most, if not all modern cars cut the fuel when coasting. Idling in neutral, on the other hand, requires fuel to keep the engine turning.
Click to expand...

So, the ideal solution is not to stop at red lights at all.
 
Boundary Layer
So, the ideal solution is not to stop at red lights at all.
Click to expand...
That would certainly save everyone a lot of gas. Maybe if every single intersection in the world were a roundabout...

With the drivers I see on the roads, though, I think the body shops would be rolling in money.
 
Coast in gear with electronic fuel injection. With a carb, you might be better off in neutral.

Same applies for running downhill. Downshift and engine brake. The revs are NOT consuming fuel, but they're keeping your brakes cool, and keeping your pads unused for another day.

At a light, keep the auto in drive. Keep a manual in neutral so you can release the clutch, un-stressing the release bearing (to some, the throwout bearing.)
 
It doesn't affect anything here, I still get around 2.5MPG, while the Hybrid gets 10MPG. I don't sense a change in revs, so it must use the same amount of fuel. What I drive automatically goes into Neutral when the brakes are pressed, and back in drive when the brakes are depressed.
 
racerx510
It doesn't affect anything here, I still get around 2.5MPG, while the Hybrid gets 10MPG. I don't sense a change in revs, so it must use the same amount of fuel. What I drive automatically goes into Neutral when the brakes are pressed, and back in drive when the brakes are depressed.
Click to expand...

what do you drive?
 
you could also argue that shifting into and out of neutral so often will increase wear on your transmission, if it made any real difference automakers would be using it to their advantage...
 
wfooshee
Coast in gear with electronic fuel injection. With a carb, you might be better off in neutral.

Same applies for running downhill. Downshift and engine brake. The revs are NOT consuming fuel, but they're keeping your brakes cool, and keeping your pads unused for another day.

At a light, keep the auto in drive. Keep a manual in neutral so you can release the clutch, un-stressing the release bearing (to some, the throwout bearing.)
Click to expand...
QFT.

I coast as often as possible, and especially down long hills. I love watching all the people in automatics riding their brakes down the 50 mph, 1/4 mile+ hill near here. I'm just sitting right at 50 in fifth gear, while their brakes are on the verge of glowing. :lol:
 
racerx510
It doesn't affect anything here, I still get around 2.5MPG, while the Hybrid gets 10MPG. I don't sense a change in revs, so it must use the same amount of fuel. What I drive automatically goes into Neutral when the brakes are pressed, and back in drive when the brakes are depressed.
Click to expand...
Wait, I just noticed, it only goes on neutral on 5MPH or lower, depending on if you are pressing brakes or not. This adds on to this other post.
you could also argue that shifting into and out of neutral so often will increase wear on your transmission, if it made any real difference automakers would be using it to their advantage...
Click to expand...
I don't know if it increases wear or not, I never expierienced any transmission problems that is out of my MR2, or the other pieces of craps I drive. Hmmmm....
 
If the fuel is cut off when coasting, then where does backfire come from? I know some unburned gasses are burned, but there is frequently multiple backfires.
 
Perfect Balance
If the fuel is cut off when coasting, then where does backfire come from? I know some unburned gasses are burned, but there is frequently multiple backfires.
Click to expand...
Must come from downshifting, seeing how everytime I downshift, theres a bit of smoke comming from the exhaust.
 
Fuel is either cut off or not cut off in coasting with an EFI.

The perplexity of emissions regulations means that many modern cars actually do not shut off the injectors while coasting... but with a closed throttle, they're not using much gas anyway... just enough to keep some heat in the chambers and optimize burn.
 
I am just curious, how come CVT's drop thier revs in drive lower than when you are idling? It revs about 500RPM higher (can't tell, theres no rev gauge) when in Neutral, and it's revs aren't as high when in drive. :confused:
 
Perfect Balance
If the fuel is cut off when coasting, then where does backfire come from? I know some unburned gasses are burned, but there is frequently multiple backfires.
Click to expand...

Who's car backfires multiple times when coasting?

If your hard on the throttle, then quickly let off to change gears, you may occasionally backfire, but thats usually due to a small amount of fuel escaping the chamber, often on poorly tuned cars.

Backfires on purpose built cars are a totally different story. Anti-lag systems invoke backfire to help keep turbos spooled when off throttle, and if you've ever seen a car backfire and sound like a machine gun before launching, it's usually a 2 step system.
 
racerx510
I am just curious, how come CVT's drop thier revs in drive lower than when you are idling? It revs about 500RPM higher (can't tell, theres no rev gauge) when in Neutral, and it's revs aren't as high when in drive. :confused:
Click to expand...

This is not unique to CVTs. Many transmissions idle at a higher RPM in neutral than in drive for this reason:

Wolfe
Most, if not all modern cars cut the fuel when coasting. Idling in neutral, on the other hand, requires fuel to keep the engine turning.
Click to expand...
 
backspace
Who's car backfires multiple times when coasting?

If your hard on the throttle, then quickly let off to change gears, you may occasionally backfire, but thats usually due to a small amount of fuel escaping the chamber, often on poorly tuned cars.

Backfires on purpose built cars are a totally different story. Anti-lag systems invoke backfire to help keep turbos spooled when off throttle, and if you've ever seen a car backfire and sound like a machine gun before launching, it's usually a 2 step system.
Click to expand...
Take most highly tuned cars, doesn't have to be turbocharged, rev it up and let go of the gas, it will backfire multiple times all the way down to idle.

I don't think high end race cars are tuned badly.

The misfiring system is different, you can tell the difference usually quite easily.
 
Perfect Balance
Take most highly tuned cars, doesn't have to be turbocharged, rev it up and let go of the gas, it will backfire multiple times all the way down to idle.

I don't think high end race cars are tuned badly.

The misfiring system is different, you can tell the difference usually quite easily.
Click to expand...

You didn't mention race cars.

The majority of highly tuned cars run custom fuel maps or other variable tuning software. The ability to adjust AFR's throughout the rev range opens up lots of possibilities. They may run slightly rich on engine deceleration to be on the safe side, and I imagine it could even help cool the combustion chamber.
 
+1... tuned cars usually run a bit rich, and you get backfire on the coast-down. Heck, my car backfires when I engine brake down a hill sometimes.

Heck, my car backfires a lot when the engine is warm... :lol:

RE: CVTs.... low drivetrain-drag losses doesn't mean no drivetrain drag losses. In other words, when you're sitting in "D" at a stop, there's still drag on your engine, thus lower revs. When you pop it into "N", it'll idle higher.
 

Latest Posts

Back