Drive for fun, for free!
Discussion
Fuel economy.
I know, I know - Pistonheads is a site for motoring enthusiasts who like to drive high performance cars fast, which isn't in any way compatible with economic driving. A few years ago, a friend of mine bought a large, high performance saloon, powered by a very substantial V8 engine. Someone asked him "what about fuel economy?" And he gave the best answer I've yet heard to such a pointless question.
"Well, when it looks like the fuel is getting low, I just stop and put some more in."
We all know that fuel economy has nothing to do with enthusiastic driving, but how much of your driving is actually enthusiastic? By which I mean, how much of your driving is carried out on nice roads, in light traffic in circumstances which allow you to really stretch your cars legs?
I have a daily commute of 23 miles which takes in about a quarter of the M60 at peak hours, and so I reckon that only about 5% of my own driving is enjoyable these days. Add to that the fact that fuel is very expensive and despite some minor fluctuations, its unlikely to ever be considered cheap again and the benefits of an economic driving style become clear.
My thinking is this. If I drive economically when the traffic is heavy and there is little or no opportunity to make progress or drive enthusiastically, then when the traffic is light and the road is nice, I can afford to stretch my car as much as I like and use up the fuel I've saved during the boring driving. In other words, my "fun" driving - when the opportunity arises - doesn't actually cost me anything. As the thread title suggests, when I drive for fun, it's free!
Of course, there are some people, like my friend with the V8, who are lucky enough to not have to worry about the cost of fuel, but even if you are one of those people, what if you're out on a run and you misjudge things and find yourself low on fuel and miles from the nearest garage? In these circumstances, an economic driving style could make the difference between continuing your journey or making that embarassing phone call.
The first thing you should note is that I'm talking about a driving style and not about differemt types of vehicles. There are cars which are promoted on the basis of being very fuel efficient and there are a number of tips floating around the internet on how to ensure your car will use as little fuel as possible - high tyre pressures and weight reduction are two examples I can think of off the top of my head - but this thread is about how to get maximum MPG (or gas mileage if you're a Yankee Doodle) when driving any car, irrespective of whether it's a hyper-efficient supermini or a V12 supercar. The techinques are the same for any car, and the benefits (in percentage MPG terms) can be very similar for any car.
The other thing to remember is that economic driving on the road is like any other style of road driving - a compromise. In much the same way that you cannot safely drive a car to the limit of its performance on the road, it wouldn't be appropriate, most of the time, to drive a car to the limit of its fuel economy capability. You wouldn't, for instance, want to crawl along a motorway slip road with minimal acceleration and then attempt to join a fast-moving lane 1.
Its this difference between real-world driving and unrealistic test conditions which results in the often large differences between manufacturers claimed fuel economy figures and the MPG figures which are realistically attainable in everyday driving. I'll be examining a slightly more practical economic driving style which doesn't assume that you want to take all day to complete your journey.
So lets start with the basics. Firstly, remember that you're trying to achieve maximum miles per gallon. In other words, the distance travelled is just as important as the driving style, so there is no real need to crawl everywhere at a snails-pace.
Secondly, the activities which use up most of your fuel are accelerating and driving uphill. Now, obviously, those activities cannot be avoided in day-to-day driving, but if you think ahead and plan your pogress, you can easily improve your fuel economy.
Thirdly, air resistance is a problem, but again, it's an element of basic physics which you cannot avoid. Driving into a headwind can have a very dramatic effect on fuel economy and even without a headwind, when you're driving At higher speeds (70mph+), most of your fuel is being used to overcome the resistance of the air. If I'm driving in miser mode, I tend to stay within the posted speed limits.
The fourth and final principle to remember is that when travelling downhill, in gear, with your foot completely off the throttle, a car is using virtually no fuel whatsoever. Many reports (and my own car manual) state that a car is using no fuel at all when coasting in gear, but I find that difficult to accept - although I'm happy to be corrected by someone more knowledgable. Whatever the truth on this question, coasting in gear (as opposed to coasting in neutral or with the clutch depressed - which allows the engine to drop to idle revs, which does require the use of some fuel) is the most fuel-efficient state to be travelling in and effectively gives you "free" mileage.
So, how do we string all these principles together into an economic driving style? Lets look at acceleration first - this is the real killer when it comes to fuel economy, so the less acceleration you have to carry out, the better.
Momentum is king when it comes to MPG, so a good advanced driver is already at an advantage in this regard. If you can plan ahead to avoid having to slow unecessarily for hazards, get an early view at a roundabout so you can join it without having to come to a stop, and maintain reasonable speed through a series of bends using acceleration sense rather than having to brake and then accelerate again - all principles of good, advanced driving - then you're on your way to developing an economic driving style.
If, however, you stop at every hazard and roundabout before accelerating away, and use a "clog and anchor" style, using heavy braking and accelerating through corners, then you're likely to use much more fuel than is necessary.
Of course, some acceleration is necessary, and I find that using no more than the first quarter of the throttle pedal's travel is generally enough to make reasonable progress in most circumstances. Try to combine the quarter pedal technique with maximum revs of 2000rpm before changing up a gear and (in most cars at least) you'll be using as little fuel as possible.
Be flexible though - as mentioned previously, if you're joining a motorway, take a flexible gear and use as many revs as you need to match the speed of vehicles in lane 1, but once you've reached your desired speed, there is no need to go through every gear sequentially - just pop it into top gear, relax your pressure on the accelerator and sit at your desired speed with as little pressure on the pedal as required to maintain your speed.
I mentioned up-hills earlier and these require a little planning. Try to maintain, or even gain a little speed on the approach to an uphill stratch, and then aim to reach the top with as little throttle as possible. I'm not a big fan of losing speed for no apparant reason, but gradully losing a little speed on an uphill incline is usually fine and most other drivers generally do it without even realising.
A smooth driving style is a big advantage when you're in miser mode. If you're smooth and gentle - not just with the accelerator, but with the brakes also - then your MPG will improve. Treat the pedals as though there's an egg underneath them.
Many cars these days are fitted with stop-start systems. These systems recognise when the car is stationary and in neutral, and then switch off the engine whilst the car remains stationary. Dipping the clutch to take first gear causes the engine to re-start almost instantly and you're ready to go.
When I first tried a couple of cars with this system, I hated it - it felt very unnatural and I turned it off. I'm now on my second car with stop-start fitted and I leave it on all the time. I got used to it and I simply cannot argue with the fact that an idling, stationary car is using fuel when it really doesn't need to. I was originally concerned about battery life, but I've never had a problem in 30-odd thousand miles, so I'm now a proponent of stop-start systems.
Maintaining a constant speed once you're up and running is important. If your speed is inconsistant, it invariably will involve a constant pattern of unecessary deceleration, followed by unecessary acceleration - the MPG killer. So once you're up to your chosen speed, keep a regular check on your speedo and try to keep your speed constant.
And the final point I mentioned - coasting in gear - is the biggest fuel-saver of all. On any downhill gradient whatsoever, you should aim to reduce your throttle presssure to zero. Take your foot completely off the pedal if it helps. If you want to maintain or increase your speed, leave the car in a higher gear which will minimise engine braking. Alternatively, if you want the car to hold you or reduce your speed a little, take a lower gear - the revs may rise, but fuel use is still (virtually) zero, so don't worry about the raised engine speed.
This all may sound, to some of you, like very basic stuff. I've only scratched the surface to be homest and there are some far more extreme fuel saving methods discussed elsewhere on the internet, but I think this will do as a basic introduction.
And don't forget to use all that fuel that you save by going on a good blast every now and again!
I know, I know - Pistonheads is a site for motoring enthusiasts who like to drive high performance cars fast, which isn't in any way compatible with economic driving. A few years ago, a friend of mine bought a large, high performance saloon, powered by a very substantial V8 engine. Someone asked him "what about fuel economy?" And he gave the best answer I've yet heard to such a pointless question.
"Well, when it looks like the fuel is getting low, I just stop and put some more in."
We all know that fuel economy has nothing to do with enthusiastic driving, but how much of your driving is actually enthusiastic? By which I mean, how much of your driving is carried out on nice roads, in light traffic in circumstances which allow you to really stretch your cars legs?
I have a daily commute of 23 miles which takes in about a quarter of the M60 at peak hours, and so I reckon that only about 5% of my own driving is enjoyable these days. Add to that the fact that fuel is very expensive and despite some minor fluctuations, its unlikely to ever be considered cheap again and the benefits of an economic driving style become clear.
My thinking is this. If I drive economically when the traffic is heavy and there is little or no opportunity to make progress or drive enthusiastically, then when the traffic is light and the road is nice, I can afford to stretch my car as much as I like and use up the fuel I've saved during the boring driving. In other words, my "fun" driving - when the opportunity arises - doesn't actually cost me anything. As the thread title suggests, when I drive for fun, it's free!
Of course, there are some people, like my friend with the V8, who are lucky enough to not have to worry about the cost of fuel, but even if you are one of those people, what if you're out on a run and you misjudge things and find yourself low on fuel and miles from the nearest garage? In these circumstances, an economic driving style could make the difference between continuing your journey or making that embarassing phone call.
The first thing you should note is that I'm talking about a driving style and not about differemt types of vehicles. There are cars which are promoted on the basis of being very fuel efficient and there are a number of tips floating around the internet on how to ensure your car will use as little fuel as possible - high tyre pressures and weight reduction are two examples I can think of off the top of my head - but this thread is about how to get maximum MPG (or gas mileage if you're a Yankee Doodle) when driving any car, irrespective of whether it's a hyper-efficient supermini or a V12 supercar. The techinques are the same for any car, and the benefits (in percentage MPG terms) can be very similar for any car.
The other thing to remember is that economic driving on the road is like any other style of road driving - a compromise. In much the same way that you cannot safely drive a car to the limit of its performance on the road, it wouldn't be appropriate, most of the time, to drive a car to the limit of its fuel economy capability. You wouldn't, for instance, want to crawl along a motorway slip road with minimal acceleration and then attempt to join a fast-moving lane 1.
Its this difference between real-world driving and unrealistic test conditions which results in the often large differences between manufacturers claimed fuel economy figures and the MPG figures which are realistically attainable in everyday driving. I'll be examining a slightly more practical economic driving style which doesn't assume that you want to take all day to complete your journey.
So lets start with the basics. Firstly, remember that you're trying to achieve maximum miles per gallon. In other words, the distance travelled is just as important as the driving style, so there is no real need to crawl everywhere at a snails-pace.
Secondly, the activities which use up most of your fuel are accelerating and driving uphill. Now, obviously, those activities cannot be avoided in day-to-day driving, but if you think ahead and plan your pogress, you can easily improve your fuel economy.
Thirdly, air resistance is a problem, but again, it's an element of basic physics which you cannot avoid. Driving into a headwind can have a very dramatic effect on fuel economy and even without a headwind, when you're driving At higher speeds (70mph+), most of your fuel is being used to overcome the resistance of the air. If I'm driving in miser mode, I tend to stay within the posted speed limits.
The fourth and final principle to remember is that when travelling downhill, in gear, with your foot completely off the throttle, a car is using virtually no fuel whatsoever. Many reports (and my own car manual) state that a car is using no fuel at all when coasting in gear, but I find that difficult to accept - although I'm happy to be corrected by someone more knowledgable. Whatever the truth on this question, coasting in gear (as opposed to coasting in neutral or with the clutch depressed - which allows the engine to drop to idle revs, which does require the use of some fuel) is the most fuel-efficient state to be travelling in and effectively gives you "free" mileage.
So, how do we string all these principles together into an economic driving style? Lets look at acceleration first - this is the real killer when it comes to fuel economy, so the less acceleration you have to carry out, the better.
Momentum is king when it comes to MPG, so a good advanced driver is already at an advantage in this regard. If you can plan ahead to avoid having to slow unecessarily for hazards, get an early view at a roundabout so you can join it without having to come to a stop, and maintain reasonable speed through a series of bends using acceleration sense rather than having to brake and then accelerate again - all principles of good, advanced driving - then you're on your way to developing an economic driving style.
If, however, you stop at every hazard and roundabout before accelerating away, and use a "clog and anchor" style, using heavy braking and accelerating through corners, then you're likely to use much more fuel than is necessary.
Of course, some acceleration is necessary, and I find that using no more than the first quarter of the throttle pedal's travel is generally enough to make reasonable progress in most circumstances. Try to combine the quarter pedal technique with maximum revs of 2000rpm before changing up a gear and (in most cars at least) you'll be using as little fuel as possible.
Be flexible though - as mentioned previously, if you're joining a motorway, take a flexible gear and use as many revs as you need to match the speed of vehicles in lane 1, but once you've reached your desired speed, there is no need to go through every gear sequentially - just pop it into top gear, relax your pressure on the accelerator and sit at your desired speed with as little pressure on the pedal as required to maintain your speed.
I mentioned up-hills earlier and these require a little planning. Try to maintain, or even gain a little speed on the approach to an uphill stratch, and then aim to reach the top with as little throttle as possible. I'm not a big fan of losing speed for no apparant reason, but gradully losing a little speed on an uphill incline is usually fine and most other drivers generally do it without even realising.
A smooth driving style is a big advantage when you're in miser mode. If you're smooth and gentle - not just with the accelerator, but with the brakes also - then your MPG will improve. Treat the pedals as though there's an egg underneath them.
Many cars these days are fitted with stop-start systems. These systems recognise when the car is stationary and in neutral, and then switch off the engine whilst the car remains stationary. Dipping the clutch to take first gear causes the engine to re-start almost instantly and you're ready to go.
When I first tried a couple of cars with this system, I hated it - it felt very unnatural and I turned it off. I'm now on my second car with stop-start fitted and I leave it on all the time. I got used to it and I simply cannot argue with the fact that an idling, stationary car is using fuel when it really doesn't need to. I was originally concerned about battery life, but I've never had a problem in 30-odd thousand miles, so I'm now a proponent of stop-start systems.
Maintaining a constant speed once you're up and running is important. If your speed is inconsistant, it invariably will involve a constant pattern of unecessary deceleration, followed by unecessary acceleration - the MPG killer. So once you're up to your chosen speed, keep a regular check on your speedo and try to keep your speed constant.
And the final point I mentioned - coasting in gear - is the biggest fuel-saver of all. On any downhill gradient whatsoever, you should aim to reduce your throttle presssure to zero. Take your foot completely off the pedal if it helps. If you want to maintain or increase your speed, leave the car in a higher gear which will minimise engine braking. Alternatively, if you want the car to hold you or reduce your speed a little, take a lower gear - the revs may rise, but fuel use is still (virtually) zero, so don't worry about the raised engine speed.
This all may sound, to some of you, like very basic stuff. I've only scratched the surface to be homest and there are some far more extreme fuel saving methods discussed elsewhere on the internet, but I think this will do as a basic introduction.
And don't forget to use all that fuel that you save by going on a good blast every now and again!
I have three cars with large displacement engine and to be honest, after all other expenses are taken into account, the cost of fuel is insignificant when you're looking at fuel consumption of 10-14, 12-15 or 17-25. Your friend's assertion is way off the mark because the main concern is planning a lengthy journey minimising fill-ups while never leaving yourself low. Filling huge tanks every two hours is a pain that you try and avoid, so with limited range, you need plan re-fuelling carefully.
We also have some other cars and my current daily driver has the best fuel consumption I have ever realised however there are some other considerations.
1. Fuzzy-logic engine control systems adapt instantly to large engine demands but are also very slow to return to economical, laid back driving. Two days with my partner driving and she murders the consumption I should achieve over the next few days even after short and long term on board consumption systems have been reset.
2. Observed over numerous, 25+ cars I have used over the last few years, on identical roads at the exact same speed fuel consumption varies significantly even is similar ambient conditions. DPF re-generations were never a factor.
3. Each car has an ideal speed to achieve maximum economy and a larger engine will often give better returns at higher cruise speeds than a smaller one. You did cover this to some extent but different car, different speed and different mpg vary and have to be learned.
4. Stop/start has next to no effect on my current daily driver however previous vehicles, from a different manufacturer, suffered instantly any town work was encountered and stop/start was of benefit.
5. Stop/start takes a heavy toll on mechanical components and potential fuel savings will have to be paid for by expensive repairs later in the vehicle life.
6. Stop/start is blind to local road conditions. Having a big heavy diesel shudder as it continually cycles, often because of poor traffic light utilisation, requires constant attention to switching it on/off on cars where it may actually provide benefit.
Please don't take this as criticism, everything you say is all good. I'm only hoping to add more content to consider.
I think your "Drive for fun, for free" is a perfect title and I genuinely do this just to add a "little extra" to my driving pleasure each day. I always drive to the maximum posted limits, accelerate at the same rate as the vehicle in front, never hold traffic behind me up, never sacrifice momentum when I can see through corners and in all honesty never get bored of driving: Probably because I get to choose what time of day I travel and never get caught in a rush hour commute.
At the end of the day, this is just a further measure to assess at the end of a drive. Like all genuine driver self-assessments they provide real benefit
We also have some other cars and my current daily driver has the best fuel consumption I have ever realised however there are some other considerations.
1. Fuzzy-logic engine control systems adapt instantly to large engine demands but are also very slow to return to economical, laid back driving. Two days with my partner driving and she murders the consumption I should achieve over the next few days even after short and long term on board consumption systems have been reset.
2. Observed over numerous, 25+ cars I have used over the last few years, on identical roads at the exact same speed fuel consumption varies significantly even is similar ambient conditions. DPF re-generations were never a factor.
3. Each car has an ideal speed to achieve maximum economy and a larger engine will often give better returns at higher cruise speeds than a smaller one. You did cover this to some extent but different car, different speed and different mpg vary and have to be learned.
4. Stop/start has next to no effect on my current daily driver however previous vehicles, from a different manufacturer, suffered instantly any town work was encountered and stop/start was of benefit.
5. Stop/start takes a heavy toll on mechanical components and potential fuel savings will have to be paid for by expensive repairs later in the vehicle life.
6. Stop/start is blind to local road conditions. Having a big heavy diesel shudder as it continually cycles, often because of poor traffic light utilisation, requires constant attention to switching it on/off on cars where it may actually provide benefit.
Please don't take this as criticism, everything you say is all good. I'm only hoping to add more content to consider.
I think your "Drive for fun, for free" is a perfect title and I genuinely do this just to add a "little extra" to my driving pleasure each day. I always drive to the maximum posted limits, accelerate at the same rate as the vehicle in front, never hold traffic behind me up, never sacrifice momentum when I can see through corners and in all honesty never get bored of driving: Probably because I get to choose what time of day I travel and never get caught in a rush hour commute.
At the end of the day, this is just a further measure to assess at the end of a drive. Like all genuine driver self-assessments they provide real benefit
Edited by Kinky on Sunday 9th November 23:50
Mattt said:
Good post but I believe that coasting in neutral has been proven more efficient due to lack of mechanical drag, even new BMWs disconnect the transmission when coasting in eco modes (from what I've read).
Any chance you can supply the sources of this proof? Regarding new BMWs; mine's a 14 plate. If it ever decides to whack itself into neutral on the move I'll be demanding my money back 
but again, I would be interested in a link to what you read.Regarding coasting for free...
In gear is better than neutral, in gear the engine is being turned over by the momentum of the car, in neutral the engine is having to idle, using fuel to keep itself turning.
A modern direct injection engine will use zero (not virtually zero) fuel when in gear, moving with the engine above idle speed. It will completely remove the fueling command. I'd imagine indirect injection (i.e. regular petrol engines) also removes fueling and ignores the lambda sensor but I just work with diesel engines so can't be 100%.
In gear is better than neutral, in gear the engine is being turned over by the momentum of the car, in neutral the engine is having to idle, using fuel to keep itself turning.
A modern direct injection engine will use zero (not virtually zero) fuel when in gear, moving with the engine above idle speed. It will completely remove the fueling command. I'd imagine indirect injection (i.e. regular petrol engines) also removes fueling and ignores the lambda sensor but I just work with diesel engines so can't be 100%.
7mike said:
Mattt said:
Good post but I believe that coasting in neutral has been proven more efficient due to lack of mechanical drag, even new BMWs disconnect the transmission when coasting in eco modes (from what I've read).
Any chance you can supply the sources of this proof? Regarding new BMWs; mine's a 14 plate. If it ever decides to whack itself into neutral on the move I'll be demanding my money back but again, I would be interested in a link to what you read.Another feature of the ECO PRO Mode is the coasting function in combination with Steptronic transmission: if within a speed range of 50–160 km/h the driver takes their foot off the accelerator and does not brake, the system disconnects the engine and the car coasts – i.e. rolls without engine power.
Benrad said:
Regarding coasting for free...
In gear is better than neutral, in gear the engine is being turned over by the momentum of the car, in neutral the engine is having to idle, using fuel to keep itself turning.
But in gear you have the decelerating effect of engine braking whereas in neutral you don't.In gear is better than neutral, in gear the engine is being turned over by the momentum of the car, in neutral the engine is having to idle, using fuel to keep itself turning.
Long, straight, flat road... Imagine you start from stationary and accelerate up to, say, 60. That will use a certain amount of fuel. Now lift off in gear and you will slow down, eventually coming to a stop, burning zero fuel as you slow.
Now do the same again but this time when you lift off, pop it into neutral. Accelerating up to speed will use the same amount of fuel as before, but this time you will be burning a little bit of fuel as you slow. However, you will travel a lot further before eventually coming to a stop because you don't have engine braking slowing you down, and even though this time your deceleration phase used some fuel, if you work out your mpg over these two experiments it will probably be better in the second one because, while you burnt a bit more fuel, you travelled a lot more distance.
The other way of looking at it: you and I are both on this road and we have to travel, say, 5 miles along it. We both accelerate up to 60 and maintain that speed, burning matching amounts of fuel as we do so. We are both going to come to a stop at the finish line 5 miles down the road. You are going to slow by lifting off in gear, while I slow by lifting off and coasting in neutral. You will have the benefit of using zero fuel as you slow, but I will be able to lift off earlier than you because I won't have any engine braking so my momentum will take me further after I lift off. The gain you make by not burning any fuel as you slow will probably be more than offset by the extra fuel you had to burn to maintain 60mph for longer after I'd already lifted off. Overall, my mpg will probably be better than yours.
Obviously those experiments are very artificial to illustrate the point, but you will see hypermilers talking about coasting to save fuel and that is the effect they are aiming to take advantage of.
As to how good an idea it is to drive like that, Reg had that covered at the start
R_U_LOCAL said:
...it wouldn't be appropriate, most of the time, to drive a car to the limit of its fuel economy capability.
waremark said:
Fromhttp://www.bmw.com/com/en/newvehicles/5series/sedan/2013/showroom/efficiency/eco_pro.html#more
Another feature of the ECO PRO Mode is the coasting function in combination with Steptronic transmission: if within a speed range of 50–160 km/h the driver takes their foot off the accelerator and does not brake, the system disconnects the engine and the car coasts – i.e. rolls without engine power.
The point is that engine braking wastes more fuel than idling. If you are going to need to stop then leave the drive engaged. If you have far enough to go before stopping that you don't need engine braking then if you want max economy you should disconnect the drive.Another feature of the ECO PRO Mode is the coasting function in combination with Steptronic transmission: if within a speed range of 50–160 km/h the driver takes their foot off the accelerator and does not brake, the system disconnects the engine and the car coasts – i.e. rolls without engine power.
PS Post crossed with SK425
Edited by waremark on Monday 10th November 14:43
The modern Porsche dual clutch systems do this disengaging thing, you can be cruising along and out of the corner of your eye notice the rev counter just drop and then pick up again if you move the gas peddle. It's quite disconcerting, but clearly coasting at 70 in neutral is more economical than being in gear with the gas engaged.
waremark said:
Fromhttp://www.bmw.com/com/en/newvehicles/5series/sedan/2013/showroom/efficiency/eco_pro.html#more
Another feature of the ECO PRO Mode is the coasting function in combination with Steptronic transmission: if within a speed range of 50–160 km/h the driver takes their foot off the accelerator and does not brake, the system disconnects the engine and the car coasts – i.e. rolls without engine power.
Thanks for the link; interesting. I've driven a few F30 520s & 530s and even considered buying one but found it so automated and uninvolving a decided against. I'm sure BMW have worked out this is all very safe but for me, just another reason I'm glad I didn't Another feature of the ECO PRO Mode is the coasting function in combination with Steptronic transmission: if within a speed range of 50–160 km/h the driver takes their foot off the accelerator and does not brake, the system disconnects the engine and the car coasts – i.e. rolls without engine power.
Its always the same with these posts - I leave it a couple of days and then think of more observations I could have included. Here are a couple I've subsequently remembered:
With reference to coasting in gear v coasting in neutral, having carried out a little more internet research, it would appear that most modern engines do not use any fuel when coasting in gear, so any progress you can make in gear with a closed throttle would, indeed, constitute "free" miles.
The bit I failed to mention, however, is that coasting should always be carried out in gear anyway - irrespective of whether you're in miser mode or not. Coasting in neutral or with the clutch depressed is bad practice and removes an element of control from the driver. It is occasionally necessary to use some acceleration to avoid an emerging hazard, and coasting in neutral introduces an unecessary delay which isn't present when you're coasting in gear.
I understand that some automatic and DSG gearboxes do allow some neutral coasting, but these systems instantly re-engage drive if the throttle is applied.
The other point I missed was one mentioned by another poster - eco pro and other switchable "eco", "sport" etc. systems.
These systems allow the driver to switch between different throttle maps to suit their intended driving style. Most cars these days employ "fly by wire" throttles, which means that the accelerator pedal is no loger directly connected to the throttle mechanism by way of a cable. Instead, the pedal effectively sends an electronic signal to an actuator, which then operates the throttle.
This means that manufacturers can tune the throttle to respond in different ways. I have a new BMW, which has three settings - a default "comfort" setting, a "sport" setting and an "eco pro" setting.
The default comfort setting gives a straightforward, linear feeling throttle, by which I mean that the engine's output seems to be directly proportionate to the amount of pressure applied to the accelerator. Pretty much identical to how a more traditional, cable-operated accelerator feels.
The sport setting effectively "shortens" the virtual accelerator cable and makes the engine - in it's lower rev range at least - feel much more responsive. I'm not sure if any other electric trickery is employed in this mode, but the impression to me is that the throttle mechanism is "geared up", and the accelerator pedal requires much less of a "prod" to get the car moving.
The third setting - eco pro - seems to do exactly the opposite to the sport setting. It seems to "lengthen" the virtual throttle cable, and in order to get the car to accelerate at anything approaching a brisk pace, it requires a very hefty shove on the accelerator pedal. The idea is that the car is doing what you should be doing and softening your inputs on the accelerator pedal to maximise fuel efficiency. The car manual also states that the air-con runs in a more fuel efficient way, heated mirrors are slower to work etc.
To the mechanically uneducated - Mrs Local for example - the car "feels" faster in sport and slower in eco pro. This isn't the case in reality, as all the cars performance is always available all the time, whatever mode you are in, it just requires different degrees of accelerator pressure to extract it.
If I'm on the daily grind, I tend to use eco pro to help with fuel economy, but the jury is out on how effective it is. I reckon I can match my fuel economy in all three modes, but I've not had the car long enough (or been anal enough yet) to try.
Incidentally, my daughter thinks "comfort" mode is ridiculous, because ther isn't an "uncomfortable" mode.
With reference to coasting in gear v coasting in neutral, having carried out a little more internet research, it would appear that most modern engines do not use any fuel when coasting in gear, so any progress you can make in gear with a closed throttle would, indeed, constitute "free" miles.
The bit I failed to mention, however, is that coasting should always be carried out in gear anyway - irrespective of whether you're in miser mode or not. Coasting in neutral or with the clutch depressed is bad practice and removes an element of control from the driver. It is occasionally necessary to use some acceleration to avoid an emerging hazard, and coasting in neutral introduces an unecessary delay which isn't present when you're coasting in gear.
I understand that some automatic and DSG gearboxes do allow some neutral coasting, but these systems instantly re-engage drive if the throttle is applied.
The other point I missed was one mentioned by another poster - eco pro and other switchable "eco", "sport" etc. systems.
These systems allow the driver to switch between different throttle maps to suit their intended driving style. Most cars these days employ "fly by wire" throttles, which means that the accelerator pedal is no loger directly connected to the throttle mechanism by way of a cable. Instead, the pedal effectively sends an electronic signal to an actuator, which then operates the throttle.
This means that manufacturers can tune the throttle to respond in different ways. I have a new BMW, which has three settings - a default "comfort" setting, a "sport" setting and an "eco pro" setting.
The default comfort setting gives a straightforward, linear feeling throttle, by which I mean that the engine's output seems to be directly proportionate to the amount of pressure applied to the accelerator. Pretty much identical to how a more traditional, cable-operated accelerator feels.
The sport setting effectively "shortens" the virtual accelerator cable and makes the engine - in it's lower rev range at least - feel much more responsive. I'm not sure if any other electric trickery is employed in this mode, but the impression to me is that the throttle mechanism is "geared up", and the accelerator pedal requires much less of a "prod" to get the car moving.
The third setting - eco pro - seems to do exactly the opposite to the sport setting. It seems to "lengthen" the virtual throttle cable, and in order to get the car to accelerate at anything approaching a brisk pace, it requires a very hefty shove on the accelerator pedal. The idea is that the car is doing what you should be doing and softening your inputs on the accelerator pedal to maximise fuel efficiency. The car manual also states that the air-con runs in a more fuel efficient way, heated mirrors are slower to work etc.
To the mechanically uneducated - Mrs Local for example - the car "feels" faster in sport and slower in eco pro. This isn't the case in reality, as all the cars performance is always available all the time, whatever mode you are in, it just requires different degrees of accelerator pressure to extract it.
If I'm on the daily grind, I tend to use eco pro to help with fuel economy, but the jury is out on how effective it is. I reckon I can match my fuel economy in all three modes, but I've not had the car long enough (or been anal enough yet) to try.
Incidentally, my daughter thinks "comfort" mode is ridiculous, because ther isn't an "uncomfortable" mode.
As I've become a better and smoother driver I'm less busy at the controls and my brakes and tyres (if comparing like for like) also seem to last a lot longer than they did 15 years ago, even driving at similarly brisk pace and, despite the fact other cars are faster on Paper, don't feel that a large estate with 'only' 140-odd bhp is actually hindering my progress.
I've turned into my Dad.
I've turned into my Dad.
Edited by MC Bodge on Wednesday 12th November 23:27
Edited by MC Bodge on Wednesday 12th November 23:31
egor110 said:
any tips for smooth driving with a automatic, we have to brake more because we have no engine braking.
Automatics tend to have less engine braking, but the effect is still there, it just requires better forward observations and planning to avoid unecessary braking.I thing spending some time in an automatic is a very good excersise to improve your acceleration sense, anticipation and throttle timing.
Have a read of Acceleration Nonsense and Braking Bad for some tips on how to improve your acceleration sense, reduce your unecessary braking and improve your braking when its necessary.
R_U_LOCAL said:
Automatics tend to have less engine braking, but the effect is still there, it just requires better forward observations and planning to avoid unecessary braking.
I thing spending some time in an automatic is a very good excersise to improve your acceleration sense, anticipation and throttle timing.
Have a read of Acceleration Nonsense and Braking Bad for some tips on how to improve your acceleration sense, reduce your unecessary braking and improve your braking when its necessary.
Will do , but if i'm coming up to say a round about i'll take my foot off the gas but i'm still going to have to brake because the cars constantly pulling, same as driving thru a town i can leave a big gap between me and the car in front but if i coast i'm still going to be coasting faster than manual and will have to brake.I thing spending some time in an automatic is a very good excersise to improve your acceleration sense, anticipation and throttle timing.
Have a read of Acceleration Nonsense and Braking Bad for some tips on how to improve your acceleration sense, reduce your unecessary braking and improve your braking when its necessary.
egor110 said:
Will do , but if i'm coming up to say a round about i'll take my foot off the gas but i'm still going to have to brake because the cars constantly pulling, same as driving thru a town i can leave a big gap between me and the car in front but if i coast i'm still going to be coasting faster than manual and will have to brake.
Is that a problem? It sounds like you think it is, but if so, why?If you need more control when driving an automatic switch to the manual option. Depending on what car you are driving and the number of auto gears, you may need to choose manual 3rd in a 30 zone. On a level road you will then have some flexibility under your right foot to gently accelerate or decelerate without having to brake to maintain an appropriate hold back position from the traffic ahead.
I have an 8 speed auto box, sometines 3rd is appropriate, sometimes 4th, if it's downhill then maybe 2nd, it depends...
Using the manual option on sustained downhill stretches of road will help control the vehicle and reduce or eliminate the need for constant braking. Manual gear selection will add another dimension to a spirited drive out of town along sweeping country lanes - try it, you may find that you'll enjot it.
I have an 8 speed auto box, sometines 3rd is appropriate, sometimes 4th, if it's downhill then maybe 2nd, it depends...
Using the manual option on sustained downhill stretches of road will help control the vehicle and reduce or eliminate the need for constant braking. Manual gear selection will add another dimension to a spirited drive out of town along sweeping country lanes - try it, you may find that you'll enjot it.
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