Does shifting into neutral save fuel

[THKPIC]

Ok, I'm not advocating this technique...officially....but I've always driven my manuals in neutral when opportunity exists to decrease gas consumption. Recently I've found numerous articles stating that in fact it does not increase gas mileage. Few reasons are as follows:

1) Most fuel management programs increase fuel to engine at or slighly below 1k RPM to keep car at idle more so than letting the engine rotate at 1500-2000k.

2) Even with the engine running at a higher RPM without applying throttle fuel managment automatically cuts off gas.

Well, thats about it. I think I got the general jist of it correct. Downhill coasting appears to me the biggest fact that mileage is affected in gear. You have the tranny working against the car gaining speed, thus decreasing distance. Tranny holds the car back when going downhill.

Maybe I'm an idiot, so someone educate me. So far the MPG estimator seems to confirm my theory...shifting into idle increases fuel economy.

Chime in..

 

[Eric Smit]

If you are going downhill, and can safely increase the speed by going into neutral, do that, but as soon as you get to the bottom of the hill, put it in gear.

General rule of thumb, if you need to slow down, keep it in gear.

If you really want to debate, you need to weigh the distance of the hill and the speed you will gain vs. the benefit of getting infinite miles per gallon.


-Eric Smit

 

[jim_de_hunter]

Instantaneous gas mileage meter on my wife's Fit shows better than 40 mpg (max for the meter) whenever I shift to neutral while it's moving. Once stopped and still in neutral, the reading comes back to within readable range.

 

[sbpphoenix]

Instantaneous gas mileage meter on my wife's Fit shows better than 40 mpg (max for the meter) whenever I shift to neutral while it's moving. Once stopped and still in neutral, the reading comes back to within readable range.

That has more to do with the transmission module. It thinks its travelling at speed at low rpm, hence the high, inaccurate mpg. Instantaneous MPG is useless.

Sent from my SAMSUNG-SGH-I727 using Tapatalk 2

 

[jim_de_hunter]

That has more to do with the transmission module. It thinks its travelling at speed at low rpm, hence the high, inaccurate mpg. Instantaneous MPG is useless.

The above statement is ignorant of the facts.

 

[cbonanno]

All the hypermilers I have talked to say it does. But most of them actually turn the car completely off. But there is no need to do that. If your RPMs are lower you are saving gas. Period.

 

[SooperSonic]

I've found that keeping the car in gear going down hill saves gas (injector shutoff) as well as saves brakes.

just my .02

 

[SSpeckerwood]

i know when i average 52mpg on my commute to work i always put it in nuetral when i can.
it seems i can get around 45-46mpg when i do the same commute without putting it in nuetral.

 

[theenico]

Just like all the above posts, I can only say it depends. Different scenarios will yield different results.

Ultimately, you'll just have to experiment. There will be times when leaving it in gear hits the sweet spot of the fuel shutoff and there will be times when the neutral coast will be more adventageous.

I should run for politics. I just wrote four sentences that said absolutely nothing,

 

[LS1notFOUND]

All the hypermilers I have talked to say it does. But most of them actually turn the car completely off. But there is no need to do that. If your RPMs are lower you are saving gas. Period.

for all purposes when in fuel cut, the engine is "off" and you still maintain power steering.

Instead of neutral, shift to overdrive, it has little to know ability to slow you down on a hill unless your well into and above the 80mph range. My 1.8L spins in the 4K neighboorhood in 5th at 90mph.

 

[Eric Smit]

I browse hypermiler websites, and I challenge someone to find where a serious gas saver would advise someone to coast in neutral vs. having no fuel (either injector shutoff or shutting off the vehicle). Search pulse and glide, which involves turning off your vehicle, if you want real MPG gains.


-Eric Smit

 

[THKPIC]

Pulse and glide...now thats what I'm talking about. I bought this car to tinker around with max fuel and hupermilling. I think fairings and weight shavings is next. Will try. I've been putting it in neutral whenever possible, but this tank og gas I'm going to try and only keep it in gear at all times (sixth whenever possible) and compare results. I'm averaging 36-37 per tank, but I actually think its higher than that when I do the math as I fill up at the same time every week when the miles left reaches (fill).

 

[Smartdave]

I also shift into neutral when going down hill, and I do it think it helps with mpg

 

[Eric Smit]

Pulse and glide...now thats what I'm talking about. I bought this car to tinker around with max fuel and hupermilling. I think fairings and weight shavings is next. Will try. I've been putting it in neutral whenever possible, but this tank og gas I'm going to try and only keep it in gear at all times (sixth whenever possible) and compare results. I'm averaging 36-37 per tank, but I actually think its higher than that when I do the math as I fill up at the same time every week when the miles left reaches (fill).

Good luck.


-Eric Smit

 

[wingman]

If you really want to know reset instant mpg display and go downhill in gear to a certain marker alongside the road. Turn around and go back up the same hill and do it all over again, reset display then put it in neutral. That should clear up any speculation.

 

[ChevyDude82]

Actually I've started using this technique, it seems to help however my miles to empty readout goes crazy when I am coasting downhill in neutral which I don't understand then when I shift back into drive sometimes my gas gauge goes down or up as does my miles to empty its just very strange. But I can't help but think it would help more than hurt your mileage, anyone correct me i I'm wrong about this.

 

[J T]

Keep the RPMs low for maximum mpg...that's what I've always tried to stick to. I can't imagine an engine idling at 1000rpm is using more gas than one spinning at 2000+ rpm. But I don't know how the fuel injection system works in this car, so I have no idea if my logic is true or not. For now, I will just assume that if I coast down a hill with the engine idling that it's using less fuel than if I were in 6th gear pushing 2000 rpm or more. If anyone wants to correct (aka educate) me, feel free.

 

[SuperFudd]

I regularly get at least 30 mpg from my 3.8L 4 speed automatic Buick Regal by limiting the rpm to 2k. It will go 70 mph at 2k.
Not sure the following applies to Sonics but it seems to me if you are going down hill, foot off the gas, at 2k or even 3k, you are using no more gas than at idle.

 

[LS1notFOUND]

I browse hypermiler websites, and I challenge someone to find where a serious gas saver would advise someone to coast in neutral vs. having no fuel (either injector shutoff or shutting off the vehicle). Search pulse and glide, which involves turning off your vehicle, if you want real MPG gains.


-Eric Smit

still because of the loss of powersteering I would never shut the car off, plus the loss of abs and stabilty, an adverse situation wouldn't go well....ever hit the brakes a few times in a dead car, you start to loose pedal after a few pumps.

 

[Eric Smit]

still because of the loss of powersteering I would never shut the car off, plus the loss of abs and stabilty, an adverse situation wouldn't go well....ever hit the brakes a few times in a dead car, you start to loose pedal after a few pumps.

You always need to exercise caution when using the pulse and glide technique, and is best performed on a wide open road with minimal hills.


-Eric Smit