Coasting in Neutral: a complete waste of time?

[akcapeco]

Just wondering why it is that some people argue that coasting in neutral is a complete waste of time.

My own findings are that coasting made a big difference in my mileage... that and "engine off at stop."

[ptsmith24]

I haven't experimented too much with coasting in neutral. As far as my RPMs go: At city speeds, the RPMs usually drop close to idle whether I change to neutral or not. I think it depends more on the vehicle and how the ECU sets up RPMs based on gearing and vehicle speed.

[Clev]

It has been my experience over the last 1,600 miles or so, that the more neutral coasting I do, the better my mileage has been. I think this breaks down into two factors:

1. Injector cut-off happens at higher-RPM, foot-off-gas slowing, but only to a point. (I can coast down from high RPM to low RPM, and at around 2,500 RPMs, I start to hear a little burble from my loud exhaust, indicating that at least some fuel is starting to be reintroduced.)

2. There are areas where neutral allows longer coasting. For instance, going through my downtown, if I keep it in gear (even 5th), there's just enough drag that I have to give it a bit of gas at all times to keep moving at speed. However, when I throw it in neutral, I can coast the entire 1.5-2 miles without my speed wavering between 24 and 28 (slightly hilly area). This happens at many places in town--I can pulse to 30, and then glide down to 25, sometimes over the course of several miles. Yes, key-off would be more efficient, but neutral can be more efficient than occasional acceleration in the same area.

[SVOboy]

Who says it's a waste of time? My MPGuino begs to differ,

[azraelswrd]

Who are these people that are arguing this??? I've got 3 months of driving that shows neutral driving is improving my MPG.

[Big Dave]

I coast in neutral as much as possible. My heavy, but not draggy truck easily coasts three-quarters of a mile.

[Tony Raine]

i just started coasting in N to lights that are either already red, or that i know are going to change. i also started sitting in N at lights too. tried turning the engine off once i stopped at long lights. worked for a little while, but my truck started to get a little hard starting. i know its not the battery (optima yellow top), i guess my truck is just getting a little worn at 110,000 miles.

i'm about to enter a fuel log to see if it made any difference. other than the N coast i haven't changed my driving style, and its the same route, day after day.


*edit. no real change. but it hasn't gone down, so thats good. i do have a CEL thats been on for a long time thats hurting my mpg no matter what

[DifferentPointofView]

I don't know, but I think its just the AMC 4.0L Engine in my Jeep. Coasting in neutral hasn't helped my mileage at all, it seems I get better MPG's coasting in drive. and at higher speeds my tranny shifts back into drive hard.

Now putting it in neutral when coming to a red light or when the light is red HAS helped.

It all depends on your ecu and what happens at higher speeds. My car coasts slightly better in drive in my Jeep. I think this is what happens:

-ECU uses same amount of fuel coasting in drive or neutral
-neutral, car uses idle fuel amount, but its not pushing any of the power to wheels
-drive, car uses idle fuel amount, but that fuel is actually being used to power wheels
-drive gets the added push from the wheels, which actually lowers resistance.

My technique:
Coast down to speed in drive, and once I hit about 15 while slowing down, I whip into neutral and come to the stoplight in neutral.

Thats saved me more in gas than neutral coasting all the time. Now thats just my Jeep. Totally different than other vehicles. This goes off tank to tank only, no instrumentation (I got a vacuum guage once, it was crap and I sent it back for a replacement... never got one back).

[ankit]

I also don't believe that it is a waste of time. But I only coast in neutral if I know im going to stop before shifting back into drive. I don't want to risk messing up the transmission. EOC in neutral is where the money is at (that's right I ended my sentence with a preposition, shoot me ).

[whokilledthejams]

I spend lots of time in neutral. I need to get more aggressive about my EOC, though. I could probably get some good gains if I just rolled around with my engine off more.