Coasting vs engine braking

[sutty2006]

3 hours ago, Sir Snipes said:

But if you're engine braking isn't that putting load on the engine? 

Not enough to be detrimental to engine wear. 

[dollywobbler]

Engine braking is actually helpful if running an engine in. I like to be in the right gear at all times. Coasting isn't something I feel comfortable with, but maybe today's kids do with all this 'gears to go, brakes to slow' nonsense. 

My main objection is what if I need to accelerate to avoid a tricky scenario? If I'm in gear, I just floor it. If I'm coasting, I need to re-engage a gear, release the clutch and then floor the throttle. You know, scenarios like you're passing a truck and it needs to move into your lane. 

[Bren]

23 minutes ago, dollywobbler said:

Engine braking is actually helpful if running an engine in. I like to be in the right gear at all times. Coasting isn't something I feel comfortable with, but maybe today's kids do with all this 'gears to go, brakes to slow' nonsense. 

My main objection is what if I need to accelerate to avoid a tricky scenario? If I'm in gear, I just floor it. If I'm coasting, I need to re-engage a gear, release the clutch and then floor the throttle. You know, scenarios like you're passing a truck and it needs to move into your lane. 

A salient point Ian. However this is autoshite - flooring the throttle is pointless for the toss some of us drive.?

[dave j]

I sometimes Coast when on a long journey in the vw camper. Not for fuel economy but sometimes to give the engine a rest! 

[MikeR]

A lot of things on a car such as the steering assist , brake servo , rely on the engine turning over , if your coasting and the quietly ticking over engine cuts out ..........  certainly would not do this on a Meriva 

[Conan]

I always engine brake, I'm even able to engine brake to complete stop with long enough stopping distance. However, if engine braking actually saves fuel, I must've offset it with rev matching every downshift. I have to admit my decision to make engine braking a habit started purely because I like the engine going vroom.

[Snipes]

2 hours ago, sutty2006 said:

Not enough to be detrimental to engine wear. 

No I was  thinking more on the impact of trying to mingebag max mpgs. 

[Tadhg Tiogar]

Unfortunately with a traditional automatic it's not possible to coast and then engage a gear whilst still moving, otherwise I would do it with the CX.

With the dizzler Borat (manual), so much momentum can be generated that coasting becomes entirely practical and really does help with fuel economy. 

[myglaren]

57 minutes ago, Conan said:

I always engine brake, I'm even able to engine brake to complete stop with long enough stopping distance. However, if engine braking actually saves fuel, I must've offset it with rev matching every downshift. I have to admit my decision to make engine braking a habit started purely because I like the engine going vroom.

I was in college with a lad who had a friend with an old moggy, who used to do engine braking that caused the thing to backfire. Enhanced by turning off the ignition for a few seconds.

He was demonstrating this to my college pal, down a very long hill.  He had turned the ignition off, turned it back on near the bottom of the hill and it made an impressive 'boom' as it blew the back box to smithereens.

[SiC]

ZF 8spd gearboxes used in a lot of cars (especially BMWs) will flick into neutral at times of coasting. But then it can go back into gear at a split moment. 

I prefer to keep in gear and use the engine to brake. Will be less efficient due to pumping losses but I prefer knowing I'm a single pedal press to be back on the power. Probably why the pads on my car last easy 20k and usually 30k+. 

On downhill sections I take great pride in selecting the right gear and letting the engine do the braking. Unlike most people in front who seem to be binary on the brakes nowadays. 

[dozeydustman]

I wouldn’t recommend coasting, but this may be 19 1/2 years of HGV driving experience, where even the tiniest of inclines either way on a seemingly level road you will gain or lose momentum very rapidly.

I find it more economical in a truck to keep the rev counter in the green zone and use an appropriate gear for the situation (if I’m driving a manual), and a retarder if fitted.

I apply this to driving the cars and get 3-4mpg more per tank than the wife or madam do.

[Luxxo Waftybarger]

I think the cost of the wear on brakes exceeds MPG gains unless you are not using the brakes at all when coasting. Ok you might save a few pence per journey but that doesn't make up for the cost of new discs and pads you might otherwise have avoided. 

[bunglebus]

I agree completely - I use the engine to slow down when I can see I need to ahead, I wouldn't use coasting in general. 

It was more a question of whether it's helpful on a decline where you can maintain speed (and what opinions about it were in general)

[myglaren]

I will admit to an evil amusement when the throttle/brake club members following me are startled at the car slowing down but no brake lights showing.

 

[HMC]

Engine braking is wonderful with marginal brakes. I tend to do it more in the a30 to help regulate my speed and try not to lean on them too much.

 

[HMC]

I’m a bit of a Le Mans 24hr obsessive and have a few books that are fairly Data heavy. Interesting to see when people started having brake trouble (Used to be common and a big problem on repeated deceleration and heat cycling after the long strait) that They’d work the transmission more and usually retire with gearbox failure in the end.

A pretty extreme example and coasting not common unless somebody miscalculated the fuel strategy.

[Talbot]

8 hours ago, dollywobbler said:

with all this 'gears to go, brakes to slow' nonsense

Not nonsense.  The point of this statement is that you shouldn't be changing down through every gear in the gearbox when slowing for a bend/junction/roundabout/whatever.  The process is that you use gears to accelerate and then hold your cruising speed, then as you approach an "item" in the road, you brake to whatever speed is correct for it, and then change gear ONCE before driving on/away.

Not approaching a roundabout in 5th, then simultaneously braking and changing into 4th, then 3rd, then 2nd, then 1st and then stopping (or possibly going in 2nd.)  That sort of shenanigans will definitely increase wear on just about everything.

When I've taught people to drive (and everyone I've taught so far has passed their test 1st time with minimal minor faults)  I've always extended the "Mirror Signal Maneuver" mnemonic into "Mirror Signal Speed Gear Go" and it works for every single obstacle you come across on the road.  Sometimes you may be able to omit a step (EG you don't need to signal to go around a bend) but this just works, and fits in with the "brakes to slow, gears to go" statement.  Which is included in literature from the Institute of Advanced Motorists, and has been true for at the very least 30 years, probably longer.

 

[New POD]

All i can say is my brakes last forever. 

[Snipes]

11 hours ago, HMC said:

Engine braking is wonderful with marginal brakes. I tend to do it more in the a30 to help regulate my speed and try not to lean on them too much.

 

I remember when the Quattro Audi A4s were dominating the British Touring Cars back in the late 90s the 4 wheel engine braking was one of the things that was apparently giving them such an advantage. 

[MrBiscuits]

Engine braking every time in a manual. A few years driving proper Minis with drums all round and no servo taught me the lost art of anticipation.

Daily driver now is a Toyota hybrid, this has very little natural engine braking, have to remind myself that hanging on the brake a bit downhill is actually OK. Above about 20mph all braking is regen, no friction loss and free energy in the battery. There is an engine braking mode on the transmission but I've never found a hill steep enough to need it.

[wuvvum]

I use engine braking a lot in the Renault 6.  Low gearing and light weight mean it slows down quite well on the engine alone - I can quite often go for miles even on busy roads without touching the brake pedal.  The Rover 75 on the other hand has pretty much zero engine braking (unless I bang it down through the gears manually, which probably won't do the 'box a lot of good in the long term) and is a heavy bastard so does get through brake pads.

[rickvw72]

I used to use a bump start system on my 70s Beetle in the winter When the carb froze up.

it was like an early stop start system really, foot ofF throttle - engine cuts out. Drop a gear, clutch out, off you go.
 

You could also use heel and toe, but this would be undesirable in an emergency stop situation. You need both feet for the pedal, and left arm for handbrake.

[Cord Fourteener]

I'm sure older shite have their own various quirks, but I'm sure that in most cases with engine management the fuel is cut off whilst on a trailing throttle, ie in gear and foot off, so engine braking is saving both fuel and brake fade and brake wear. As has been talked about here.

Further to that though, I have got into a flow driving the hilly b roads using heel-tow to down change while on the brakes, so I'm always using engine and brakes together.

When slowing down slowly on a straight road or when stoppages are anticipated well in advance I will simply lift off accelerator and attempt to slow to a roll before brakes are necessary, besides the fuel and brake savings directly you often get to see any traffic lights change before you've come to a complete stop.

One thing that annoys me is coming to a sudden stop then 'having' to inch forwards when at lights.

When hypermiling, people say that the more you are using the brakes, the more it is indicative of burning unnecessary fuel.

[bunglebus]

50 minutes ago, rickvw72 said:

You could also use heel and toe, but this would be undesirable in an emergency stop situation. You need both feet for the pedal, and left arm for handbrake.

You'd have to have deformed feet to heel and toe in a Beetle. Much as I like them, the pedal arrangement is...odd

[Tadhg Tiogar]

2 minutes ago, bunglebus said:

You'd have to have deformed feet to heel and toe in a Beetle. Much as I like them, the pedal arrangement is...odd

Tried floor hinged pedals once. Never again. 

[sutty2006]

I often wonder why some larger passenger vehicles don’t have proper engine/exhaust brakes. For example. My discovery 3 is great for towing my twin axle caravan, but being automatic has very limited engine braking when the caravan is doing the pushin. Would benefit greatly from an exhaust brake to reduce speed coming off motorway slip roads or down steep inclines. Just a thought. 

[PhilA]

17 hours ago, myglaren said:

I will admit to an evil amusement when the throttle/brake club members following me are startled at the car slowing down but no brake lights showing.

 

I was taught to use the engine to slow, but press enough to operate the switch on the brake light pedal and display the lights to indicate to the driver behind your reduction in speed.

Obviously the same doesn't work so well on a car with lights activated by hydraulic pressure but the lights on the car are mostly there for the benefit of others.

11 minutes ago, Tadhg Tiogar said:

Tried floor hinged pedals once. Never again. 

I have a floor hinged gas pedal and the brake pedal's hinge point is well under the floor in the chassis. That's quite strange but not unpleasant to operate. 

 

Phil

[Eyersey1234]

22 hours ago, dollywobbler said:

Engine braking is actually helpful if running an engine in. I like to be in the right gear at all times. Coasting isn't something I feel comfortable with, but maybe today's kids do with all this 'gears to go, brakes to slow' nonsense. 

My main objection is what if I need to accelerate to avoid a tricky scenario? If I'm in gear, I just floor it. If I'm coasting, I need to re-engage a gear, release the clutch and then floor the throttle. You know, scenarios like you're passing a truck and it needs to move into your lane. 

I agree Ian, though when I learned to drive in 2004-5 using brakes for slowing was what was thought then. 

[PhilA]

3 minutes ago, sutty2006 said:

I often wonder why some larger passenger vehicles don’t have proper engine/exhaust brakes. 

Moderately common here for diesels that are purchased to tow with to have a compression brake system on the exhaust retrofitted, along with either electrically actuated hydraulic or direct electric operated brakes on the trailer.

[Eyersey1234]

20 minutes ago, sutty2006 said:

I often wonder why some larger passenger vehicles don’t have proper engine/exhaust brakes. For example. My discovery 3 is great for towing my twin axle caravan, but being automatic has very limited engine braking when the caravan is doing the pushin. Would benefit greatly from an exhaust brake to reduce speed coming off motorway slip roads or down steep inclines. Just a thought. 

Buses are fitted with retarders that slow the engine down without using the brakes, I wonder if one would help your Discovery