What is Coasting - Part 2

What is Coasting? and how do you stop yourself doing it? This is the second part of 2 videos explaining this subject. I also address a point from comments on the first video, that some people think coasting saves fuel!

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[Carnology]

I like that insanely wide angle camera you have, never seen anyone else use that in a car. Very good to see a full view from a learners perspective to see what you're seeing when you pull out.

[tommyneil]

Some pupils don't want to bring the clutch up when going downhill because there foot is on the brake they think the car will stall if they bring the clutch up while on the brake

As long as the car is at the correct speed for the gear it won't stall

[jeremyashford]

I remember doing all this in a paddock in my grandfather’s Ford Consul fifty years ago!

[ivang]

I'm learning to drive... and the videos are helping!!! Keep it up

[richardsanderson]

This is really interesting Ashley and has started firing all sorts of questions. As a trainee PDI, lockdown is allowing me to digest lots of sources, including your channel, and this video (and it's Part 2) make some points that seem to contradict techniques 2 and 3 of the ECOWILL driving project.
I would be interested to get your take on this as an experienced ADI instructor as I am using the ECOWILL information as one source for my Eco-driving lesson plans
Many thanks Ashley....

[davidrumming]

Yep I was always told (many years ago) to be in the right gear for the corner by the time you go round the corner. I’ll be perfectly honest, it’s been a while since I drove a manual (stick shift) car, and seeing this just reminded me about how much extra work is involved. In built up areas it’s not like u just do it once, your constantly changing gear almost every few yards. One of my coworkers admits he drives with his left hand always on the gear stick.

[mrgarypitman]

love your camera setup. This is exactly how i was taught to drive. If more people used the gears on motorways to slow, it would stop all the breaking lights you see now a days. or just eased off the accelerator.

[forresten]

I often get 'scolded' by a few of my acquaintances that I waste fuel when going down hill, while in gear. Their approach is to speed up (more than permitted) and just drop the gear to neutral and use the momentum, to roll down the hill, and even start climbing the next one.
Fuel consumption aside, you can feel a difference, when the engine is linked into the propulsion (foot off the gas - engine braking in effect) and when in neutral (feels like a dead weight in the chassis).
Thank you, Ashley for proving that leaving it in neutral/clutching in actually is worse for consumption, than leaving it in gear, and let the wheels 'turn' the engine.

[crocket]

This video with the camera angle would have been so helpful when I was learning to drive. Great work

[Harzenpool]

Loving the new camera angle!
Great improvements to your videos! keep it up.

[kuksoolwonuk]

I only ever did this once whilst learning to drive and going downhill, never did it again after that as it was the scariest thing I've ever done, had no control of the car whatsoever!

[micheals]

One thing that I don't understand, you have to pass your test in a manual to drive one, but on a CBT you can pass on a 50cc twist and go and then get on your 125cc geared motorbike and drive it without any training. I was terrified of my motorbike for the first few weeks riding it until I got used to the gears and clutch. The first time I got on it I nearly flipped the bike xD

[jiasui]

Video saved hopefully get it sorted before my next test

[ekhaat]

That's why I love the one pedal driving of my EV

[kisan-majdoorkalyansamiti]

Coasting always not bad for reverse and in right uphill turn in 2nd gear not possible without coasting car will stall .
Coasting has also some benifites but most of cade should avoid

[TimpBizkit]

Does coasting save fuel? Really it depends on the circumstances. If you have a technical or windy downhill, or a stop at the bottom of a hill or any other situation where you can't safely use all the speed of the car on the hill, then you're better off slowing down in a gear, engaging deceleration fuel cut off than letting it idle in neutral. I tried to do an experiment on the way home from work - coasting vs not coasting. I think I got 52 mpg not coasting and about 54 with (I kept the engine on), but it's hard to tell whether I drove faster on one than the other, though I think I drove faster on the coasting run. I would have thought the average losses in the engine would be slightly greater on the non coasting run, seeing as you can use the engine to slow a car, does it use more fuel to counteract a "slowing" or does the throttle open more, reducing the air resistance?

I will note my car doesn't engage DFCO until above 2500 rpm, but then will remain in DFCO when slowing down further. I coasted down a hill in my citroen, which at about 40 will give me around 300 mpg (basically telling me the engine will use a gallon for 7-8 hours of idling) I put it in 5th gear and the mpg went to like 150-200 - telling me the engine was actually using a bit more fuel, perhaps the same per stroke as at idle, but more strokes because the rpm was just under 2000 at 40. Now slowing down in 4th gear was enough to trigger DFCO and my car gauge got up to 999 mpg (the highest possible reading).

What if you don't intend to slow down?

If you have a powerful car with shorter gearing, you might be more economical giving it a quick spurt of power at medium rpm and then gliding along in neutral, than continuing at part load in gear with the engine turning faster - assuming the road is clear and safe to do so. You build a speed with quick spurts of power, and then freewheel like a bicycle until the car has slowed enough for a second shot of power. Probably that high powered BMW would see gains not turning the oversized engine around at driving speed for the duration of the trip.

I haven't had any negative or dangerous experiences with coasting in neutral, but I'm not going to recommend it, just saying that I do it quite a lot - coming up to stop lights I only have to worry about the brake pedal, not declutching and can come to a complete stop without fear of stalling. It tends to be my default "I might need to stop but not yet" mode.

Some people get extreme and turn the engine off when they coast. This is not recommended because the brake pedal assist goes down, making it harder to stop quickly in an emergency. I have done it before although not with any passengers and not when busy. It mainly gets used if there is a queue of traffic down a hill. I can just roll along a couple of car lengths and then stop again, securing with the hand brake rather than idling for half an hour, which uses enough fuel to drive a few extra miles. In this situation speeds are low.

Another thing to add - keeping a clutch pedal pressed down for extended periods of time can cause more where on the release bearings, that are rolling against pressure trying to close the clutch plates. This is not always coasting related, but can be done at a stoplight.

Also you will fail your test if you coast in neutral in this way.

[micheals]

Coasting only saves fuel if you're on a hill where you're basically using the throttle to eliminate engine braking, although it's not a massive amount in fuel savings so it's better keeping it in gear so you can better control the speed.

[jiasui]

Failed my driving test Today because I'm coasting all the time when i turning right or left. Thanks for ur video and i going to Working hard on this

[TransportCambs]

Nice video Ashley, can't wait to learn to drive.

[djmike]

Will you talk about coasting when a sudden stop/slowing down is needed. I personally know at first it can become a question of when you press the clutch as you want to stop quickly but also not stall the car. Doesn't necessarily mean an emergency stop but anything that causes a faster stop than usual. I didn't get much teaching around it and the other day I actually had to slow down very quickly but used the clutch far too early which left me pressing the brakes a lot harder and afterwards they even felt a bit softer. I think it's a good lesson to teach since you have to do everything a lot more quickly without wearing out the brakes/causing an accident.