Is engine braking good or bad?
Discussion
Like FK I am also a fan of engine braking, by looking far into the distance (limit point) you can judge it very well if the traffic around you allows, my record for not touching the brakes is joining the M1 at Junction 36 just north of Sheffield, then going to the M40/A34 where I was lucky the lights were green on the roundabout. I had to eventually use them at the junction of the A34/M3 (roundabout with lights) a little over 200 miles. I tried to keep a steady 70 MPH, and just "feathered" the gas pedal depending on what was going on in front of me, changing lanes to go around slower vehicles with plenty of time not getting boxed in. Took me 3.5 hours from junction 36 M1 to junction 2 M27.....result!
Driving in Northern Ireland and Donegal earlier this year was a real pleasure for both engine braking and on some of the more interesting roads using "road craft" to really getting the fun and most out of my MX5, so little traffic, great views ahead made driving such a pleasure over there. Every PH reader should drive over there to enjoy our passion for driving/cars as they should be!
a few comments ago folk were worrying about clutch wear. using an "eco" style of driving, engine braking where possible, good use of "block" changing we get through few clutches in our house we have a 19.5 year old Volvo with 241,000 miles still on first clutch, and my teaching Mini one diesel has 141,000 on the clock in 5 years of learners trying to destroy it. Yes the bite is high, but has been for about 2 years now, it can still pull away in second gear if gentle with it. I suspect that it will require a new clutch soon, but, for a standard car there is no excuse for clutches to be destroyed for anything less than 200k miles unless you have a poor gear changing technique. I hear some clutches being replaced after 40k miles....what are they doing?!!!!
Driving in Northern Ireland and Donegal earlier this year was a real pleasure for both engine braking and on some of the more interesting roads using "road craft" to really getting the fun and most out of my MX5, so little traffic, great views ahead made driving such a pleasure over there. Every PH reader should drive over there to enjoy our passion for driving/cars as they should be!
a few comments ago folk were worrying about clutch wear. using an "eco" style of driving, engine braking where possible, good use of "block" changing we get through few clutches in our house we have a 19.5 year old Volvo with 241,000 miles still on first clutch, and my teaching Mini one diesel has 141,000 on the clock in 5 years of learners trying to destroy it. Yes the bite is high, but has been for about 2 years now, it can still pull away in second gear if gentle with it. I suspect that it will require a new clutch soon, but, for a standard car there is no excuse for clutches to be destroyed for anything less than 200k miles unless you have a poor gear changing technique. I hear some clutches being replaced after 40k miles....what are they doing?!!!!
My name's Will and I'm an engine braker. In the last 13 years I've done 200,000 miles in my Impreza, mostly on motorways and dual carriageways. I try not to use the brakes unless coming to a stop, I rev match on downchanges and try to get round roundabouts without braking, sometimes in 3rd at 4000 revs with 400 yards to go. I've debated with people the theories that modern cars use no fuel on a closed throttle and braking uses fuel. I'm not sure if it's true or not but I average 30+mpg and the car's still on its original clutch. I get the point about displaying brake lights but I try to keep an awareness of what's behind me and their rate of closure. I have to say I do get annoyed by people braking needlessly on motorways when planning ahead and lifting off the throttle would do the same job.
Number Eight said:
My name's Will and I'm an engine braker. In the last 13 years I've done 200,000 miles in my Impreza, mostly on motorways and dual carriageways. I try not to use the brakes unless coming to a stop, I rev match on downchanges and try to get round roundabouts without braking, sometimes in 3rd at 4000 revs with 400 yards to go. I've debated with people the theories that modern cars use no fuel on a closed throttle and braking uses fuel. I'm not sure if it's true or not but I average 30+mpg and the car's still on its original clutch. I get the point about displaying brake lights but I try to keep an awareness of what's behind me and their rate of closure. I have to say I do get annoyed by people braking needlessly on motorways when planning ahead and lifting off the throttle would do the same job.
I don't know what shocks me more, that you got 200k from your Impreza, or the fact you've seen over 30mpg from it. I assume it's not a turbo?it's a WRX PPP and as I sit here it has 200,384 miles on the clock. Driven to the speed limit, with a light right foot it'll get just over 30 mpg measured by brimming the tank and doing the sums. Back to the subject of engine braking and changing down early: if I change down early in anticipation of a roundabout for instance, at 50 mph, in 3rd at 4000 rpm the engine makes more noise than in 5th at 2000 rpm. If, on a closed throttle, it's not burning fuel the only sound should be mechanical but it does sound like combustion is taking place. This leads me to believe that the no fuel used on a closed throttle theory isn't entirely correct. I'm also not sure the rate of deceleration is any greater in 3rd than in 4th or 5th? Regardless, driving as I do seems fairly economical.
Number Eight said:
M4cruiser said:
changing down early to induce braking without using the brakes (that's bad, at least it is in a modern car).
How so? What do you call modern?Braking to slow is best, that's what the brakes are designed for. It also distributes the slowing force around all the wheels, instead of just one wheel (or two if there's a limited slip diff).
Also, depending how you change down, it will cause more wear on the gears (and/or the linkage) and clutch, as opposed to leaving it in the gear it's in and then making one block change down (e.g. 4th to 1st) to pull away again.
But as mentioned earlier, you can reduce the need for braking by planning ahead and lifting off the throttle.
I asked that question to my driving instructor many moons ago when I was learning how to drive as a kid and his answer was 'brake pads are cheaper to replace than gearboxes'. So unless you're pulling a lot of weight behind you, it probably makes more sense to use your brakes more and your engine less.
Interesting thread and I've recently passed my IAM so thought I'd chip in (although I still don't consider myself an advanced driver).
I've always found the engine braking argument an odd one and especially with modern autos. I passed my IAM in an M140 and very much doubt engine braking puts more wear on the gearbox than 500Nm of acceleration.
Modern auto BMW's are interesting as they actually engine brake in sport mode. You can feel it if you're on the brakes hard going on a bend or junction, where it down shifts more aggressively than the braking applied. As a result you can feel the added assistance. In comfort mode the gearbox simply waits until you come off the brakes before block changing to what it thinks is the correct gear.
With respect, I'm pretty sure the engineers at BMW know a fair bit more than the IAM so would not set the gearbox to engine brake if it resulted in adverse wear and tear. Obviously this only applies to my experience with BMW although, as an engineer myself, I'm sure that you load a drivetrain far more under hard acceleration.
Re the OP I have a personal thing where I just don't like using brakes much at all. I will use my brake lights, often with tailgaters, but even before passing my IAM was into smooth driving that required little braking effort.
I've now changed to an i3 so is a moot point as the brake lights only come on when you either use the brakes or regen brake aggressively. Therefore with good anticipation I have journeys where my brake lights don't come on much at all.
I completely get the arguments on here that brake lights are good but should I now be driving less smoothly so that drivers behind can see what I'm up to?
I've always found the engine braking argument an odd one and especially with modern autos. I passed my IAM in an M140 and very much doubt engine braking puts more wear on the gearbox than 500Nm of acceleration.
Modern auto BMW's are interesting as they actually engine brake in sport mode. You can feel it if you're on the brakes hard going on a bend or junction, where it down shifts more aggressively than the braking applied. As a result you can feel the added assistance. In comfort mode the gearbox simply waits until you come off the brakes before block changing to what it thinks is the correct gear.
With respect, I'm pretty sure the engineers at BMW know a fair bit more than the IAM so would not set the gearbox to engine brake if it resulted in adverse wear and tear. Obviously this only applies to my experience with BMW although, as an engineer myself, I'm sure that you load a drivetrain far more under hard acceleration.
Re the OP I have a personal thing where I just don't like using brakes much at all. I will use my brake lights, often with tailgaters, but even before passing my IAM was into smooth driving that required little braking effort.
I've now changed to an i3 so is a moot point as the brake lights only come on when you either use the brakes or regen brake aggressively. Therefore with good anticipation I have journeys where my brake lights don't come on much at all.
I completely get the arguments on here that brake lights are good but should I now be driving less smoothly so that drivers behind can see what I'm up to?
M4cruiser said:
There's a difference between planning ahead and lifting off the throttle (which is good) as opposed to changing down early to induce braking without using the brakes (that's bad, at least it is in a modern car).
All imho but unless anyone can give me a convincing engineering argument as to why it isn't the case then I'm sticking to it:Engine braking does not wear the gearbox by any perceptible amount. The forces going through the gearbox are negligible relative to those from even moderate acceleration.
If the clutch isn't slipping and the torque passing through it is far less than that from the engine at full throttle then the clutch isn't going to be wearing by any perceptible amount.
Since the advent of fuel injection and the ability to shut off fuel to the cylinders there's been no mechanical downside to engine braking and much to be gained from efficiency.
There isn't really any extra wear on piston rings and cylinder walls from higher rpm since there's no high gas pressure from combustion to push the rings against the bores.
If there is no additional wear from engine braking then the argument that brake pads are cheaper than clutches holds no weight, so why not save wear on the brake pads?
Unsympathetic downshifts can destabilise the car, but that's the same as any other input including use of the brakes.
Pica-Pica said:
I don’t think you were taught that on your IAM course.
Ha, I should clarify.I don't mean the antagonistic false brake to annoy the tailgater when you've no intention on stopping but more progressive braking so that they're given advanced notice that you intend to stop i.e. at a junction or approaching a hazzard. If I check my mirrors and the car behind has left a good distance then I can brake later.
I was taught to increase the distance between me and the car in front and also to give as much info to other road users. I'm hoping that's the right thing to do!
SOL111 said:
Pica-Pica said:
I don’t think you were taught that on your IAM course.
Ha, I should clarify.I don't mean the antagonistic false brake to annoy the tailgater when you've no intention on stopping but more progressive braking so that they're given advanced notice that you intend to stop i.e. at a junction or approaching a hazzard. If I check my mirrors and the car behind has left a good distance then I can brake later.
I was taught to increase the distance between me and the car in front and also to give as much info to other road users. I'm hoping that's the right thing to do!
On a side note, with the bottom of rear windows being higher now, cars may seem closer, because you cannot see so much of the front. I found that when I hired a van with solid rear doors, I almost gave up worrying what was behind, I could not see so much, so I concentrated just what was ahead.
Pica-Pica said:
OK, I see. In your last paragraph, it is a fine balance between leaving a comfortable gap for yourself, and leaving too large a gap that will frustrate (and infuriate) the follower more.
On a side note, with the bottom of rear windows being higher now, cars may seem closer, because you cannot see so much of the front. I found that when I hired a van with solid rear doors, I almost gave up worrying what was behind, I could not see so much, so I concentrated just what was ahead.
Yes, definitely.On a side note, with the bottom of rear windows being higher now, cars may seem closer, because you cannot see so much of the front. I found that when I hired a van with solid rear doors, I almost gave up worrying what was behind, I could not see so much, so I concentrated just what was ahead.
Although sadly I infuriate almost everyone nowadays, after passing my IAM. Sticking to speed limits seems to annoy almost everyone and doing it in an EV more so.
The one that almost exclusively gets everyone's back up is showing restraint on approach to any change in speed limit and slowing down to a change in speed limit before you pass the sign. But that's another thread entirely :lol:
SOL111 said:
The one that almost exclusively gets everyone's back up is showing restraint on approach to any change in speed limit and slowing down to a change in speed limit before you pass the sign. But that's another thread entirely :lol:
So do you feel proud or embarrassed by your behaviour?Bert
I don't feel either to be honest. Should I?
It's just an observation in the same way that, since doing my IAM, it's more obvious that I'm regularly the only car on the road that vaguely sticks to the limit during my commute.
If I feel anything it's a bit sad that passing the IAM requires restraint but also being an AD involves not pissing other drivers off. So what does one do? Exceed the limits to keep the peace or stay on the right side of the law and infuriate other drivers?
Being PH I can guess the majority opinion!
It's just an observation in the same way that, since doing my IAM, it's more obvious that I'm regularly the only car on the road that vaguely sticks to the limit during my commute.
If I feel anything it's a bit sad that passing the IAM requires restraint but also being an AD involves not pissing other drivers off. So what does one do? Exceed the limits to keep the peace or stay on the right side of the law and infuriate other drivers?
Being PH I can guess the majority opinion!
SOL111 said:
I don't feel either to be honest. Should I?
It's just an observation in the same way that, since doing my IAM, it's more obvious that I'm regularly the only car on the road that vaguely sticks to the limit during my commute.
If I feel anything it's a bit sad that passing the IAM requires restraint but also being an AD involves not pissing other drivers off. So what does one do? Exceed the limits to keep the peace or stay on the right side of the law and infuriate other drivers?
Being PH I can guess the majority opinion!
I don't believe that you should feel either way.It's just an observation in the same way that, since doing my IAM, it's more obvious that I'm regularly the only car on the road that vaguely sticks to the limit during my commute.
If I feel anything it's a bit sad that passing the IAM requires restraint but also being an AD involves not pissing other drivers off. So what does one do? Exceed the limits to keep the peace or stay on the right side of the law and infuriate other drivers?
Being PH I can guess the majority opinion!
It is your decision based on what you think is good or bad practice, legal or illegal or right or wrong to do as long as the intent is not to annoy others. If you believe that what you have learned through the IAM and have been judged by someone who should have knowledge in the subject is of value then why drive differently. It is up to the other road users to make their decisions. An 'advanced' competency is to be able to make decisions that prevent you causing a crash and to prevent being involved where another road user has made a mistake.
Len Woodman said:
I don't believe that you should feel either way.
It is your decision based on what you think is good or bad practice, legal or illegal or right or wrong to do as long as the intent is not to annoy others. If you believe that what you have learned through the IAM and have been judged by someone who should have knowledge in the subject is of value then why drive differently. It is up to the other road users to make their decisions. An 'advanced' competency is to be able to make decisions that prevent you causing a crash and to prevent being involved where another road user has made a mistake.
Thanks.It is your decision based on what you think is good or bad practice, legal or illegal or right or wrong to do as long as the intent is not to annoy others. If you believe that what you have learned through the IAM and have been judged by someone who should have knowledge in the subject is of value then why drive differently. It is up to the other road users to make their decisions. An 'advanced' competency is to be able to make decisions that prevent you causing a crash and to prevent being involved where another road user has made a mistake.
I'll just stick to what I'm doing and put up with the visible cursing in my rear view mirror lol.
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