Coasting in Neutral

[thebestlittlecivicintheworld]

I’m convinced this can save vast quantities of fuel when deployed in the correct situations, ie downhill when you can see miles ahead of you.

[MikeM6]

If going downhill then keeping it in gear will use less fuel and stop you increasing speed.

[CoreyDog]

MikeM6 said:

If going downhill then keeping it in gear will use less fuel and stop you increasing speed.

This exactly.

I can't think of any situation where coasting the car in neutral would be better than leaving it in gear.

You will be riding the brakes been in neutral whilst going down hill, massively increasing brake wear and risking overheating.

[MuscleSedan]

So ….

Why does my VW DSG coast off the throttle when it is in Eco mode ?

[HustleRussell]

If you are in gear you have some engine braking however it is probably using no fuel at all.

If you are in neutral or the clutch is down you have no engine braking but the injectors are supplying fuel to keep the engine idling.

[7mike]

MuscleSedan said:

So ….

Why does my VW DSG coast off the throttle when it is in Eco mode ?

I had this discussion with a driver I trained years ago, met him again recently and he told me he had stopped using the coasting mode. His mpg improved.

[Narcisus]

7mike said:

I had this discussion with a driver I trained years ago, met him again recently and he told me he had stopped using the coasting mode. His mpg improved.

I’ve proven that I can get 4 to 5 mpg extra when using my Superb in Eco mode. You learn when to use the coast feature to full advantage.

Of course there is no way I could be arsed to do this after my initial testing period ....

[aponting389]

So does the fuel saved by coasting in gear trump the speed gained by coasting in neutral?

[MuscleSedan]

aponting389 said:

So does the fuel saved by coasting in gear trump the speed gained by coasting in neutral?

Got to be better in neutral, or, as with DSG, the transmission disengaged. On a slight downhill motorway gradient - close the throttle in gear and the car will slow quicker than if not in gear..

[Green1man]

CoreyDog said:

I can't think of any situation where coasting the car in neutral would be better than leaving it in

Really!!

A steepish downhill you are much better being in gear as you will be using zero fuel and the braking effect of the engine is useful. A gentle downhill however means the much greater coasting distance gained whilst being in neutral more than outweighs the small amount of petrol used keeping the engine running.

[Driver101]

Narcisus said:

I’ve proven that I can get 4 to 5 mpg extra when using my Superb in Eco mode. You learn when to use the coast feature to full advantage.

Of course there is no way I could be arsed to do this after my initial testing period ....

Is the 4-5mpg down to the coasting, or the fact eco mode starves the car of performance and throttle response?

Coasting in neutral only kicks in at certain times in most auto cars I've driven.

[ScoobyChris]

I too was surprised that my auto utilises coasting in eco mode when I’d been taught that leaving in gear was more economical. Seems BMW have a better understanding of this stuff than I do

Chris

[ScoobyChris]

Driver101 said:

Coasting in neutral only kicks in at certain times in most auto cars I've driven.

In mine it’s whenever you come off the throttle.

Chris

[MuscleSedan]

As you would expect, DSG Eco mode causes upshifts to be as soon as they possibly can, along with providing the coasting feature. There's no reduction in actual engine power output. Its a bit weird at first as you come off the throttle the revs drop to idle and you lose the braking effect between the engine and transmission. Its surprising how far you can go on a long gentle descent with the engine at idle though. A definite fuel saver but there's no way I could drive around using it all the time.

[Driver101]

ScoobyChris said:

Driver101 said:

Coasting in neutral only kicks in at certain times in most auto cars I've driven.

In mine it’s whenever you come off the throttle.

Chris

A quick glance says M140i?

The coast function doesn't kick in all the time. IIRC any steering input or if the car is warning you to lift off knowing a roundabout is coming it won't drop into neutral.

Eco mode in the M135i/140i is horrible. So much pedal lag it becomes highly annoying. I didn't see much benefit at all and especially for how much poorer the car is to drive.

[Pica-Pica]

BMW ZF8 has ‘coasting’ in ECO-PRO mode. However, I did not like the feel of it. It removed engine braking when I needed it, and I did not feel any other benefit from the coasting on the rare occasions that I used ECO-PRO, so I have turned it off on my 335d (via iDrive selection).

[Aidancky]

Back when I was 17 I tried this on some hilly roads i travelled often and it did seem like it saved a bit of fuel at least. If you can coast without needing to brake, as well as smoothly transition back into the correct gear at the bottom, I cant see why not.

[CoreyDog]

Green1man said:

CoreyDog said:

I can't think of any situation where coasting the car in neutral would be better than leaving it in

Really!!

A steepish downhill you are much better being in gear as you will be using zero fuel and the braking effect of the engine is useful. A gentle downhill however means the much greater coasting distance gained whilst being in neutral more than outweighs the small amount of petrol used keeping the engine running.

Really.

So on a gradual why not hold the car in 4th, 5th or even 6th?

If the car is in neutral, you are sacrificing some control over that car, what if you need to accelerate quickly to avoid an emerging hazard? All well and good sat there with a revving engine and making no more progress.

[twokcc]

Coast works in eco pro and normal(and maybe sport) on my 7speed DCT Cooper S.
Requires a lot more anticipation for roundabouts etc on NSL roads and any sayings probably out weighted by extra wear on brakes unless on long uninterrupted road without any reductions in speed required.

However is a certain satisfaction on long downward hill seeing revs on idle and speed increasing, box is very quick into putting car back into gear at any driver input. Coast only works in certain conditions i.e doesn't work with cruise control engaged.

MPG on downhill with foot off accelerator shows 99.9 mpg with coast shows ----

[ScoobyChris]

Driver101 said:

A quick glance says M140i?

The coast function doesn't kick in all the time. IIRC any steering input or if the car is warning you to lift off knowing a roundabout is coming it won't drop into neutral.

Eco mode in the M135i/140i is horrible. So much pedal lag it becomes highly annoying. I didn't see much benefit at all and especially for how much poorer the car is to drive.

Agreed - I rarely use it. I think the last time I switched it on was when the M4 was closed due to an accident and I got rerouted through unfamiliar deepest darkest Wiltshire and the fuel light came on.

Chris