Left Foot Braking
Discussion
MC Bodge said:
I did selectively edit the quote, fairly obviously. Hence the ".... ...." Which is an accepted method of doing so.
Pressing both pedals together is contrary to the Advanced Driving teachings, which is what I was highlighting.
I agree with most of your extensive and considered posts on the other topics, but on this subject there appears to be a slight hint of , "because the rules of Advanced Driving say so" -which was also my experience of Advanced Driving (but much less so of IAM biking).
Left foot braking isn't something I use often(although I have tried on a number of occasions), but I see no reason at all (other than tradition) why it shouldn't be done in a 2 pedal car. It is of course much trickier in a 3 pedal car, due to the need for switching both of the feet between the brake pedal and pressing the clutch with a very different "feel".
It would be very interesting to try left foot braking on a testing ground or track in a range of vehicles with different drivetrains to see what the outcomes/benefits might be.
I feel it was disingenuous of you to edit my post so that it appeared I wrote something completely different. I understand the point you're making, but I actually wrote that there was nothing inherently wrong with left-foot braking.Pressing both pedals together is contrary to the Advanced Driving teachings, which is what I was highlighting.
I agree with most of your extensive and considered posts on the other topics, but on this subject there appears to be a slight hint of , "because the rules of Advanced Driving say so" -which was also my experience of Advanced Driving (but much less so of IAM biking).
Left foot braking isn't something I use often(although I have tried on a number of occasions), but I see no reason at all (other than tradition) why it shouldn't be done in a 2 pedal car. It is of course much trickier in a 3 pedal car, due to the need for switching both of the feet between the brake pedal and pressing the clutch with a very different "feel".
It would be very interesting to try left foot braking on a testing ground or track in a range of vehicles with different drivetrains to see what the outcomes/benefits might be.
Edited by MC Bodge on Tuesday 31st March 23:44
In my opinion, however, the benefits of LFB are only worthwhile at, or approaching the limits of the car's grip. As such, it's my view that it's a worthwhile technique for the track, or for competitive driving, but not for the road. The OP made it clear that this was not the discussion he wanted to start, so I avoided going down that road, but seeing as how you've nudged me in that direction by misquoting me...
On the road, even if we're really pressing on, we should be well within the limits of the car and I believe there are real benefits to keeping the braking and accelerating phases completely seperate from each other. It's easier to keep the car balanced, its smoother, fits perfectly with my cornering principle of "slow and late in - quick and straight out" and is more mechanically sympathetic than left-foot braking.
Another issue is that everyone has a "fall-back" driving style which they revert to in an emergency. It's the reason that a system of car control was originally developed - so that a systematic approach to hazards becomes second-nature and an "automatic" response to emerging hazards. In an emergency, I'd hate to think that, even for half-a-second, a driver was either hesitating over which foot to operate the brakes with, or doing some kind of Michael Flatley impression with the pedals, resulting in less-than-optimal emergency braking.
There is also a danger that following drivers could be confused by your brake lights if you're braking and accelerating at the same time. Brake lights are a signal, and as with any other signals, they should not be used in a way which would confuse other road users.
You're welcome to misquote me on this post - here's your starter for 10:
Reg said:
On the road, even if we're really pressing on, we should be well within the limits of... Michael Flatley... resulting in less-than-optimal...road users.
You don't have to overlap braking and throttle to benefit from LFB. You remove the coasting time - i.e. throttle and brake are still separated but are immediately after each other, rather than there being a small delay.
A lot of 2 pedal cars wont actually allow braking and throttle at the same time (apparently, although I am not 100 % sure that is right).
A lot of 2 pedal cars wont actually allow braking and throttle at the same time (apparently, although I am not 100 % sure that is right).
R_U_LOCAL said:
Before being selectively edited Reg actually said:
I'm not saying that left-foot braking is inherantly wrong. I'm sure there are many drivers of two-pedal cars who use the technique as a matter of course without incident.
So no, operating both pedals at the same time isn't a "terrible thing" - it just goes against the police/Roadcraft/IAM (i.e. "traditional") advanced driving principles.part of the discussion was around go-karts where you have brake and accelerator separated by the steering column so have to use both feet - anyone who has done karting soon realises that you don't wait for the foot to come off the accelerator before pressing the brake - so why would you on a car other than when the left foot is operating a clutch...?
MC Bodge said:
No offence was intended. Your posts are interesting.
No offence was taken - my apologies if I gave the impression I was offended.I actually quite like being challenged - it makes me re-think the principles and ideas behind the techniques I write about in here and elsewhere. Like you, I hate asking why, and receiving the answer "because thats how we've always done it".
I use LFB by default in a 2 pedal car. It works very nicely for the transition from brakes to gas at bend entry. I cannot see any negatives. However, in this situation I do not deliberately overlap gas and brakes. I am aware that some do.
Having enjoyed a LFB course run on a loose surface by the late great Pentti Airikkola I did learn to use gas and brakes together to control the cornering line in a FWD car. Braking the rear wheels while the fronts were kept turning with plenty of power caused the back to lose grip and step out. By varying brake pressure you could control the cornering line quite effectively. I used this successfully in FWD cars during subsequent outings to frozen lakes in Sweden. Obviously this was not applicable to rear or 4wd cars - or to any situation which I have encountered on road.
Having enjoyed a LFB course run on a loose surface by the late great Pentti Airikkola I did learn to use gas and brakes together to control the cornering line in a FWD car. Braking the rear wheels while the fronts were kept turning with plenty of power caused the back to lose grip and step out. By varying brake pressure you could control the cornering line quite effectively. I used this successfully in FWD cars during subsequent outings to frozen lakes in Sweden. Obviously this was not applicable to rear or 4wd cars - or to any situation which I have encountered on road.
I would like to throw in a curve ball and say that LFB is very useful at slow speeds especially when parking or reversing. For example a little constant gas and control the motion of the car by easing or applying pressure with the left foot on the brake. I have been using this method for many years quite happily.
Another use for example is where waiting to enter a roundabout right foot ready on gas and left foot holding on brake gives an easy get away by changing pressure on feet when required.
Another use for example is where waiting to enter a roundabout right foot ready on gas and left foot holding on brake gives an easy get away by changing pressure on feet when required.
Up there with the most impressive of skills but don't practice on the road. Its akin to jumping in a left hooker (vice-versa if you're a yank) then trying to change gear with the door handle...
Book an airfield trackday and wait until it's empty at 4 o'clock that's probably the safest bet
Book an airfield trackday and wait until it's empty at 4 o'clock that's probably the safest bet
For me the biggest advantage to left foot braking on the road is from three primary areas, which are all fundamental and critical to "smooth" progress
1) No powertrain torque reversal, so the powertrain doesn't have to cross the zero torque line. This is a masisve effect in a modern car which have typically very softly suspended components and often have devices in the drive line designed to smooth out torsional vibrations (ie a DMF!!) When you left foot brake, keeping the engine in net positive torque, the engine and gearbox/diff deosn't move about on it's mounts, and the rotating components stay loaded in a single direction.
2) The different effect on dynamic stability because of where the decceleration forces are applied and how they are applied. When you brake, the longitudinal deccel force is reacted into the hubs at wheel centre height, and then reacted fairly evenly across the suspension components into the body shell. When you lift off, the deccel forces are reacted by the powertrain mounts, either resulting in lateral roll or longitudinal pitch moments, with a markedly different(negative) effect on weight transfer
3) As humans, we suck at initial "open loop" control. For example, if i asked you to balance a broom on your hand, vertically, after a bit of practise, most people quickly learn to do this, moving there hand to keep the handle directly under the head. But if i asked you to first catch a thrown broom, and then immediately balance it without dropping it, even with a lot of practice you'd struggle. This is because there is little direct feedback in the early stages of that event. And it's the same with braking. If you were say braking at 0.2g, and i said, brake harder to 0.5g, most people could smoothly increase the brake force and hold it close to that point. But if you were not braking, and had to "jump" onto the pedal and immediately try to get to exactly 0.5g, then even very very skilled drivers struggle (because the muscle memory required to "Jump" rapidly onto a pedal, and the distance / force to push the pedal to get exactly 0.5g is very difficult to master!) By left foot braking, or at least being ready to (not enough pedal input to light brake lamps for example) you have put yourself immediately in a much better position to response both rapidly and accurately if necessary
1) No powertrain torque reversal, so the powertrain doesn't have to cross the zero torque line. This is a masisve effect in a modern car which have typically very softly suspended components and often have devices in the drive line designed to smooth out torsional vibrations (ie a DMF!!) When you left foot brake, keeping the engine in net positive torque, the engine and gearbox/diff deosn't move about on it's mounts, and the rotating components stay loaded in a single direction.
2) The different effect on dynamic stability because of where the decceleration forces are applied and how they are applied. When you brake, the longitudinal deccel force is reacted into the hubs at wheel centre height, and then reacted fairly evenly across the suspension components into the body shell. When you lift off, the deccel forces are reacted by the powertrain mounts, either resulting in lateral roll or longitudinal pitch moments, with a markedly different(negative) effect on weight transfer
3) As humans, we suck at initial "open loop" control. For example, if i asked you to balance a broom on your hand, vertically, after a bit of practise, most people quickly learn to do this, moving there hand to keep the handle directly under the head. But if i asked you to first catch a thrown broom, and then immediately balance it without dropping it, even with a lot of practice you'd struggle. This is because there is little direct feedback in the early stages of that event. And it's the same with braking. If you were say braking at 0.2g, and i said, brake harder to 0.5g, most people could smoothly increase the brake force and hold it close to that point. But if you were not braking, and had to "jump" onto the pedal and immediately try to get to exactly 0.5g, then even very very skilled drivers struggle (because the muscle memory required to "Jump" rapidly onto a pedal, and the distance / force to push the pedal to get exactly 0.5g is very difficult to master!) By left foot braking, or at least being ready to (not enough pedal input to light brake lamps for example) you have put yourself immediately in a much better position to response both rapidly and accurately if necessary
Max_Torque said:
For me the biggest advantage to left foot braking on the road is from three primary areas, which are all fundamental and critical to "smooth" progress
1) No powertrain torque reversal, so the powertrain doesn't have to cross the zero torque line. This is a masisve effect in a modern car which have typically very softly suspended components and often have devices in the drive line designed to smooth out torsional vibrations (ie a DMF!!) When you left foot brake, keeping the engine in net positive torque, the engine and gearbox/diff deosn't move about on it's mounts, and the rotating components stay loaded in a single direction.
2) The different effect on dynamic stability because of where the decceleration forces are applied and how they are applied. When you brake, the longitudinal deccel force is reacted into the hubs at wheel centre height, and then reacted fairly evenly across the suspension components into the body shell. When you lift off, the deccel forces are reacted by the powertrain mounts, either resulting in lateral roll or longitudinal pitch moments, with a markedly different(negative) effect on weight transfer
3) As humans, we suck at initial "open loop" control. For example, if i asked you to balance a broom on your hand, vertically, after a bit of practise, most people quickly learn to do this, moving there hand to keep the handle directly under the head. But if i asked you to first catch a thrown broom, and then immediately balance it without dropping it, even with a lot of practice you'd struggle. This is because there is little direct feedback in the early stages of that event. And it's the same with braking. If you were say braking at 0.2g, and i said, brake harder to 0.5g, most people could smoothly increase the brake force and hold it close to that point. But if you were not braking, and had to "jump" onto the pedal and immediately try to get to exactly 0.5g, then even very very skilled drivers struggle (because the muscle memory required to "Jump" rapidly onto a pedal, and the distance / force to push the pedal to get exactly 0.5g is very difficult to master!) By left foot braking, or at least being ready to (not enough pedal input to light brake lamps for example) you have put yourself immediately in a much better position to response both rapidly and accurately if necessary
Fail to see how any of those points make LF braking of any use on the road. Why would you need to touch the brakes so lightly as to not light the lamps?1) No powertrain torque reversal, so the powertrain doesn't have to cross the zero torque line. This is a masisve effect in a modern car which have typically very softly suspended components and often have devices in the drive line designed to smooth out torsional vibrations (ie a DMF!!) When you left foot brake, keeping the engine in net positive torque, the engine and gearbox/diff deosn't move about on it's mounts, and the rotating components stay loaded in a single direction.
2) The different effect on dynamic stability because of where the decceleration forces are applied and how they are applied. When you brake, the longitudinal deccel force is reacted into the hubs at wheel centre height, and then reacted fairly evenly across the suspension components into the body shell. When you lift off, the deccel forces are reacted by the powertrain mounts, either resulting in lateral roll or longitudinal pitch moments, with a markedly different(negative) effect on weight transfer
3) As humans, we suck at initial "open loop" control. For example, if i asked you to balance a broom on your hand, vertically, after a bit of practise, most people quickly learn to do this, moving there hand to keep the handle directly under the head. But if i asked you to first catch a thrown broom, and then immediately balance it without dropping it, even with a lot of practice you'd struggle. This is because there is little direct feedback in the early stages of that event. And it's the same with braking. If you were say braking at 0.2g, and i said, brake harder to 0.5g, most people could smoothly increase the brake force and hold it close to that point. But if you were not braking, and had to "jump" onto the pedal and immediately try to get to exactly 0.5g, then even very very skilled drivers struggle (because the muscle memory required to "Jump" rapidly onto a pedal, and the distance / force to push the pedal to get exactly 0.5g is very difficult to master!) By left foot braking, or at least being ready to (not enough pedal input to light brake lamps for example) you have put yourself immediately in a much better position to response both rapidly and accurately if necessary
thiscocks said:
Fail to see how any of those points make LF braking of any use on the road. Why would you need to touch the brakes so lightly as to not light the lamps?
This can be used to pre-load the braking system so that the pads are in light contact with the discs hence removing delay, small though it is. As mentioned this can help with feedback as you have removed the unknown delay or dead pedal travel so muscle memory is better at dialling in a given level of braking. Similarly using the brake pedal to change acceleration and weight transfer can give a smoother drive as it removes the hysteresis inherent in using the throttle, also as explained above.
The gains are small and it is not something you would use all of the time, however it adds a little finesse to your drive and can be enjoyable to practice.
thiscocks said:
Max_Torque said:
For me the biggest advantage to left foot braking on the road is from three primary areas, which are all fundamental and critical to "smooth" progress
1) No powertrain torque reversal, so the powertrain doesn't have to cross the zero torque line. This is a masisve effect in a modern car which have typically very softly suspended components and often have devices in the drive line designed to smooth out torsional vibrations (ie a DMF!!) When you left foot brake, keeping the engine in net positive torque, the engine and gearbox/diff deosn't move about on it's mounts, and the rotating components stay loaded in a single direction.
2) The different effect on dynamic stability because of where the decceleration forces are applied and how they are applied. When you brake, the longitudinal deccel force is reacted into the hubs at wheel centre height, and then reacted fairly evenly across the suspension components into the body shell. When you lift off, the deccel forces are reacted by the powertrain mounts, either resulting in lateral roll or longitudinal pitch moments, with a markedly different(negative) effect on weight transfer
3) As humans, we suck at initial "open loop" control. For example, if i asked you to balance a broom on your hand, vertically, after a bit of practise, most people quickly learn to do this, moving there hand to keep the handle directly under the head. But if i asked you to first catch a thrown broom, and then immediately balance it without dropping it, even with a lot of practice you'd struggle. This is because there is little direct feedback in the early stages of that event. And it's the same with braking. If you were say braking at 0.2g, and i said, brake harder to 0.5g, most people could smoothly increase the brake force and hold it close to that point. But if you were not braking, and had to "jump" onto the pedal and immediately try to get to exactly 0.5g, then even very very skilled drivers struggle (because the muscle memory required to "Jump" rapidly onto a pedal, and the distance / force to push the pedal to get exactly 0.5g is very difficult to master!) By left foot braking, or at least being ready to (not enough pedal input to light brake lamps for example) you have put yourself immediately in a much better position to response both rapidly and accurately if necessary
Fail to see how any of those points make LF braking of any use on the road. Why would you need to touch the brakes so lightly as to not light the lamps?1) No powertrain torque reversal, so the powertrain doesn't have to cross the zero torque line. This is a masisve effect in a modern car which have typically very softly suspended components and often have devices in the drive line designed to smooth out torsional vibrations (ie a DMF!!) When you left foot brake, keeping the engine in net positive torque, the engine and gearbox/diff deosn't move about on it's mounts, and the rotating components stay loaded in a single direction.
2) The different effect on dynamic stability because of where the decceleration forces are applied and how they are applied. When you brake, the longitudinal deccel force is reacted into the hubs at wheel centre height, and then reacted fairly evenly across the suspension components into the body shell. When you lift off, the deccel forces are reacted by the powertrain mounts, either resulting in lateral roll or longitudinal pitch moments, with a markedly different(negative) effect on weight transfer
3) As humans, we suck at initial "open loop" control. For example, if i asked you to balance a broom on your hand, vertically, after a bit of practise, most people quickly learn to do this, moving there hand to keep the handle directly under the head. But if i asked you to first catch a thrown broom, and then immediately balance it without dropping it, even with a lot of practice you'd struggle. This is because there is little direct feedback in the early stages of that event. And it's the same with braking. If you were say braking at 0.2g, and i said, brake harder to 0.5g, most people could smoothly increase the brake force and hold it close to that point. But if you were not braking, and had to "jump" onto the pedal and immediately try to get to exactly 0.5g, then even very very skilled drivers struggle (because the muscle memory required to "Jump" rapidly onto a pedal, and the distance / force to push the pedal to get exactly 0.5g is very difficult to master!) By left foot braking, or at least being ready to (not enough pedal input to light brake lamps for example) you have put yourself immediately in a much better position to response both rapidly and accurately if necessary
Thiscocks: in response to your first question, all three of MT's points improve passenger comfort and safety. There are a whole load of aspects of advanced driving that contribute towards these things in a similarly small but significant way, from rev matching to steering technique - failing to do one of them doesn't mean you have an accident, but they all add up to a bigger picture. In response to your second question, MT explains that very well in his post - he's basically saying that it's easier for a person to apply a required amount of braking swiftly and accurately if they already have their foot in touch with the pedal than if they have to swap their whole foot from one pedal to the other through thin air - that seems very reasonable to me, especially if the braking is required very quickly.
thiscocks said:
Max_Torque said:
For me the biggest advantage to left foot braking on the road is from three primary areas, which are all fundamental and critical to "smooth" progress
1) No powertrain torque reversal, so the powertrain doesn't have to cross the zero torque line. This is a masisve effect in a modern car which have typically very softly suspended components and often have devices in the drive line designed to smooth out torsional vibrations (ie a DMF!!) When you left foot brake, keeping the engine in net positive torque, the engine and gearbox/diff deosn't move about on it's mounts, and the rotating components stay loaded in a single direction.
2) The different effect on dynamic stability because of where the decceleration forces are applied and how they are applied. When you brake, the longitudinal deccel force is reacted into the hubs at wheel centre height, and then reacted fairly evenly across the suspension components into the body shell. When you lift off, the deccel forces are reacted by the powertrain mounts, either resulting in lateral roll or longitudinal pitch moments, with a markedly different(negative) effect on weight transfer
3) As humans, we suck at initial "open loop" control. For example, if i asked you to balance a broom on your hand, vertically, after a bit of practise, most people quickly learn to do this, moving there hand to keep the handle directly under the head. But if i asked you to first catch a thrown broom, and then immediately balance it without dropping it, even with a lot of practice you'd struggle. This is because there is little direct feedback in the early stages of that event. And it's the same with braking. If you were say braking at 0.2g, and i said, brake harder to 0.5g, most people could smoothly increase the brake force and hold it close to that point. But if you were not braking, and had to "jump" onto the pedal and immediately try to get to exactly 0.5g, then even very very skilled drivers struggle (because the muscle memory required to "Jump" rapidly onto a pedal, and the distance / force to push the pedal to get exactly 0.5g is very difficult to master!) By left foot braking, or at least being ready to (not enough pedal input to light brake lamps for example) you have put yourself immediately in a much better position to response both rapidly and accurately if necessary
Fail to see how any of those points make LF braking of any use on the road. Why would you need to touch the brakes so lightly as to not light the lamps?1) No powertrain torque reversal, so the powertrain doesn't have to cross the zero torque line. This is a masisve effect in a modern car which have typically very softly suspended components and often have devices in the drive line designed to smooth out torsional vibrations (ie a DMF!!) When you left foot brake, keeping the engine in net positive torque, the engine and gearbox/diff deosn't move about on it's mounts, and the rotating components stay loaded in a single direction.
2) The different effect on dynamic stability because of where the decceleration forces are applied and how they are applied. When you brake, the longitudinal deccel force is reacted into the hubs at wheel centre height, and then reacted fairly evenly across the suspension components into the body shell. When you lift off, the deccel forces are reacted by the powertrain mounts, either resulting in lateral roll or longitudinal pitch moments, with a markedly different(negative) effect on weight transfer
3) As humans, we suck at initial "open loop" control. For example, if i asked you to balance a broom on your hand, vertically, after a bit of practise, most people quickly learn to do this, moving there hand to keep the handle directly under the head. But if i asked you to first catch a thrown broom, and then immediately balance it without dropping it, even with a lot of practice you'd struggle. This is because there is little direct feedback in the early stages of that event. And it's the same with braking. If you were say braking at 0.2g, and i said, brake harder to 0.5g, most people could smoothly increase the brake force and hold it close to that point. But if you were not braking, and had to "jump" onto the pedal and immediately try to get to exactly 0.5g, then even very very skilled drivers struggle (because the muscle memory required to "Jump" rapidly onto a pedal, and the distance / force to push the pedal to get exactly 0.5g is very difficult to master!) By left foot braking, or at least being ready to (not enough pedal input to light brake lamps for example) you have put yourself immediately in a much better position to response both rapidly and accurately if necessary
You brake and select a suitable gear for the upcoming corner, use the convergence/divergence to judge if the corner is opening and tightening.
Lets say it tights a bit. In a modern car, with tall gearing (even in numerically "Low" gears) just lifting off doesn't really slow you down that much, so you need to gently brake. If you brake conventionally, you have to lift all the way off the accelerator, before you brake, so the car deccelerates at the calibrated negative torque for that engine speed/gear. And because flywheel torque is negative, you cross the zero torque threshold and hence get drivetrain lash. If, as is often the case, the corner starts to open, and you realise you don't have to brake in fact, it's too late, you've lifted, and your passengers feel that!
if you left foot brake, you can lift the accelerator until the engine is still juuusstt producing positive torque, then hover over the brake pedal. if you need to say loose 4mph, a very gentle application of brakes, without any powertrain shuffle (no zero crossing, so no powertrain reversal on it's mounts etc). Do it right, and you can adjust your speed by small amounts without your passengers feeling anything!
I haven't been on here for a while , but read a review on Reg's new book on another forum and , indirectly , found my way here !
I've used left foot braking in automatic driving for about 40 years now : to me the logic was simple - two pedals and two feet , to use one foot only to drive is like hopping down the street when you can walk . Once you get used to it , it becomes instinctive and , although we have no manual cars in the household now , I can still jump into manual vehicles at work and drive them without thinking about it .
Although , as an advanced driver , one ought to have one's observations out and 'ought' never to be taken by surprise , things do occasionally happen unexpectedly and one may have to react : even in those circumstances I still find myself using my left foot , even once when I found myself instinctively cadence braking due to a diesel spill on a wet road in my early , non ABS , 190E automatic .
I agree with the above about smooth transitions , even if it does amount to BGOL ( although surprisingly , to me , when I was last out with some guys from Tulliallan I found they now teach BGOL if , for example , turning sharp left off a downhill slope ; no more almost stalling the car then off brakes , change gear , then accelerate , which always struck me as cumbersome and unsmooth ) .
Once really nice technique I found and mastered with automatic driving is , if braking on the approach to a bend , and wishing to manually take the gear before going onto the power ( to avoid the car downshifting by itself in the bend ) is to select the lower gear , if you come off the brakes before manually selecting the gear , usually there will be a 'hard' downshift which is undesirable , but if you select the lower gear whilst still braking with your left foot , nothing happens initially , but then coming smoothly onto the power - whilst still braking - brings in a part throttle downshift , following which you can smoothly transition off the brakes and progressively into the power as required to balance the car through the bend . That is very 'wordy' and much easier to demonstrate than to describe , but it works very well .
Before anyone says 'but you shouldn't do that/will damage the box' - I've been doing it for years and most of my cars go on to reach very high mileages , several beyond 200K , one beyond 300K and my record was 430K in my 300TE-24 , I've never had an automatic box failure .
While , in normal driving , I normally come off brakes before going onto power , and vice-versa , if trying to 'make progress' then it can be rewarding to purposefully and smoothly overlap the two .
I've used left foot braking in automatic driving for about 40 years now : to me the logic was simple - two pedals and two feet , to use one foot only to drive is like hopping down the street when you can walk . Once you get used to it , it becomes instinctive and , although we have no manual cars in the household now , I can still jump into manual vehicles at work and drive them without thinking about it .
Although , as an advanced driver , one ought to have one's observations out and 'ought' never to be taken by surprise , things do occasionally happen unexpectedly and one may have to react : even in those circumstances I still find myself using my left foot , even once when I found myself instinctively cadence braking due to a diesel spill on a wet road in my early , non ABS , 190E automatic .
I agree with the above about smooth transitions , even if it does amount to BGOL ( although surprisingly , to me , when I was last out with some guys from Tulliallan I found they now teach BGOL if , for example , turning sharp left off a downhill slope ; no more almost stalling the car then off brakes , change gear , then accelerate , which always struck me as cumbersome and unsmooth ) .
Once really nice technique I found and mastered with automatic driving is , if braking on the approach to a bend , and wishing to manually take the gear before going onto the power ( to avoid the car downshifting by itself in the bend ) is to select the lower gear , if you come off the brakes before manually selecting the gear , usually there will be a 'hard' downshift which is undesirable , but if you select the lower gear whilst still braking with your left foot , nothing happens initially , but then coming smoothly onto the power - whilst still braking - brings in a part throttle downshift , following which you can smoothly transition off the brakes and progressively into the power as required to balance the car through the bend . That is very 'wordy' and much easier to demonstrate than to describe , but it works very well .
Before anyone says 'but you shouldn't do that/will damage the box' - I've been doing it for years and most of my cars go on to reach very high mileages , several beyond 200K , one beyond 300K and my record was 430K in my 300TE-24 , I've never had an automatic box failure .
While , in normal driving , I normally come off brakes before going onto power , and vice-versa , if trying to 'make progress' then it can be rewarding to purposefully and smoothly overlap the two .
I am not a left foot braker and I wonder whether there is much to be gained by it. It is true that rally drivers use it to their advantage, but is it not the case that their cars have the brake bias increased on the rear wheels so that they can get the rear wheels to swing on the entrance to bends? With a normal car's brakes being heavily biased to the front wheels, is there much advantage?
On most of the cars I have owned in recent years when I have tried to apply brakes and throttle together (when drying brakes after a deep ford) the engine cuts to tickover speed as the ECU does not like brake and throttle being applied simultaneously.
On most of the cars I have owned in recent years when I have tried to apply brakes and throttle together (when drying brakes after a deep ford) the engine cuts to tickover speed as the ECU does not like brake and throttle being applied simultaneously.
xpc316e said:
On most of the cars I have owned in recent years when I have tried to apply brakes and throttle together (when drying brakes after a deep ford) the engine cuts to tickover speed as the ECU does not like brake and throttle being applied simultaneously.
^ this is a modern problem, a curse of nanny cars. It can make H&T difficult too.I'm not a turbo fan, but I believe some lfb on turbos to keeps revs up and turbo spooling.
Robert Elise said:
I'm not a turbo fan, but I believe some lfb on turbos to keeps revs up and turbo spooling.
Unless the clutch is down or you are in neutral, lfb cannot help you keep revs higher than otherwise for your speed and gear. I am not clear whether having the throttle open have keep the turbo spinning although the revs will be no higher than normal. On the Pentti Airikkala case he claimed that this did work.Gassing Station | Advanced Driving | Top of Page | What's New | My Stuff