Automatic rev matching - to use it or not to use it?
Discussion
In the 'I've switched to an 8 speed auto thread,
Previous experience of automatic rev matching was mainly in a Cayman GT4. In that, it could easily be switched off. I tried it only for long enough to find out that it was technically brilliant, then left it switched off for the remainder of my time in the car.
I have always thought that in a world of superlative paddle-shift gear changes the point of choosing a manual car is for extra driver engagement, and extra satisfaction from good use of the gearbox including accurate rev matching. I wanted a manual car for these purposes alongside paddle-shift autos. In the M2 if you don't rev match at all it does a good job for you. I never allow it to do that. If you carry out your own rev match accurately, it doesn't interfere and you wouldn't know the feature was there. However, if you get the rev match slightly wrong it will put it right.
In my first few days with the car I kept turning the traction control off in order to get the satisfaction of rev matching accurately - but I am sure that is not a good idea, the traction control is not at all intrusive even in fully on mode and is a safety aid. Since then I have been leaving the traction control on and therefore the automatic rev matching is also on. With the feature on, but also using the accelerator to rev match, it feels as though I am making excellent gear changes. However, I can generally tell if the auto rev matching has interfered to correct my revs, in which case of course I beat myself up.
I would really like the auto rev matching to be easily switchable alongside other switchable settings - but I don't think I am going to hack the car to turn it off permanently.
Would or do other folk like this feature, and if you have it how do you use it? Rob, you are welcome to have a go and find out if it ruins the car for you.
RobM77 said:
Sensible stuff including:
... in fact to not rev match would cause me unnecessary distraction (I'm not sure I'd like the 911R or 370Z that do it for you!).
Lots of other cars do it for you too, including most manual Porsches and BMW's. I have recently acquired an M2 Competition; in that you cannot turn off the automatic rev matching feature except by fully disengaging the stability control. I didn't commit to buying the car until I had found out that the car can be hacked to turn this feature off permanently.... in fact to not rev match would cause me unnecessary distraction (I'm not sure I'd like the 911R or 370Z that do it for you!).
Previous experience of automatic rev matching was mainly in a Cayman GT4. In that, it could easily be switched off. I tried it only for long enough to find out that it was technically brilliant, then left it switched off for the remainder of my time in the car.
I have always thought that in a world of superlative paddle-shift gear changes the point of choosing a manual car is for extra driver engagement, and extra satisfaction from good use of the gearbox including accurate rev matching. I wanted a manual car for these purposes alongside paddle-shift autos. In the M2 if you don't rev match at all it does a good job for you. I never allow it to do that. If you carry out your own rev match accurately, it doesn't interfere and you wouldn't know the feature was there. However, if you get the rev match slightly wrong it will put it right.
In my first few days with the car I kept turning the traction control off in order to get the satisfaction of rev matching accurately - but I am sure that is not a good idea, the traction control is not at all intrusive even in fully on mode and is a safety aid. Since then I have been leaving the traction control on and therefore the automatic rev matching is also on. With the feature on, but also using the accelerator to rev match, it feels as though I am making excellent gear changes. However, I can generally tell if the auto rev matching has interfered to correct my revs, in which case of course I beat myself up.
I would really like the auto rev matching to be easily switchable alongside other switchable settings - but I don't think I am going to hack the car to turn it off permanently.
Would or do other folk like this feature, and if you have it how do you use it? Rob, you are welcome to have a go and find out if it ruins the car for you.
Edited by waremark on Friday 18th January 19:07
Thank you Mark, I'd love a go and also to see your DB11; we'll have to sort something out soon - it's my turn to come up to you I believe.
I suspect if I owned a car that auto rev-matched then I'd double rev match for a good while before adapting to not do it, and then find it messed up my gearchanges for other cars. I've had this with the clutch delay valve in my current BMW; when I drive my wife's Civic Type R or my Formula Renault it takes me a while to adjust to a normal clutch again. I don't drive them enough to commit the change to memory, but from prior experience of switching between cars more regularly I suspect I'd soon get the ability to go back and forth, as I would with any obvious binary feature that's either there or not. What really messes with my head are more complex assistive features like Porsche's variable ratio steering; I've test driven several Porsches and never been confident enough that I'd learn it to commit to buying one.
One thing that irritates me is when manufacturers link electronic aids together as you've described for your M2C. As you point out, why would a driver who can rev match want to disable DSC entirely every time they drive the car? Have BMW assumed people like me only bother rev matching on track? For me it's an inbuilt feature of my driving that, as you've quoted me saying, I'd have to try very hard not to do. If I remember rightly, in some other BMWs you need to disable DSC to get decent throttle response, which is just barking. I recall Michael Schumacher moaning at Ferrari that he couldn't disable TC in comfort settings for everyday driving, and I think they relented and made it possible. I'm friendly with another pro driver who does the same - TC gets switched off every time he gets in his car.
I suspect if I owned a car that auto rev-matched then I'd double rev match for a good while before adapting to not do it, and then find it messed up my gearchanges for other cars. I've had this with the clutch delay valve in my current BMW; when I drive my wife's Civic Type R or my Formula Renault it takes me a while to adjust to a normal clutch again. I don't drive them enough to commit the change to memory, but from prior experience of switching between cars more regularly I suspect I'd soon get the ability to go back and forth, as I would with any obvious binary feature that's either there or not. What really messes with my head are more complex assistive features like Porsche's variable ratio steering; I've test driven several Porsches and never been confident enough that I'd learn it to commit to buying one.
One thing that irritates me is when manufacturers link electronic aids together as you've described for your M2C. As you point out, why would a driver who can rev match want to disable DSC entirely every time they drive the car? Have BMW assumed people like me only bother rev matching on track? For me it's an inbuilt feature of my driving that, as you've quoted me saying, I'd have to try very hard not to do. If I remember rightly, in some other BMWs you need to disable DSC to get decent throttle response, which is just barking. I recall Michael Schumacher moaning at Ferrari that he couldn't disable TC in comfort settings for everyday driving, and I think they relented and made it possible. I'm friendly with another pro driver who does the same - TC gets switched off every time he gets in his car.
Edited by RobM77 on Tuesday 22 January 13:18
Forgive me if I've mis-understood you, but the point of rev matching is twofold:
The word 'sympathy' is very deliberate. You are not going to break your car or crash if you fail to rev-match when driving on the public road at a sensible speed (although you may have a scary moment in the wet in a Caterham, TVR or similar). The thing is, no aspect of car control taught in advanced road driving will result in you actually crashing if you fail to do it. Similarly roadcraft elements such as signalling, showing brake lights, positioning your car to see and be seen, etc - they are all layers of safety that build up, such that if one is lost you're still ok. Personally, I continue to do all of the above because I like as many layers as possible. Personally I've not let the clutch out after a downchange without rev-matching since about a week after I passed my test; I just wouldn't consider it.
- Mechanical sympathy: Rev matching prevents the clutch and gearbox from receiving a sudden load if the speeds of one side and the other aren't the same and then are suddenly brought together by the clutch.
- Dynamic sympathy: Rev matching prevents the driven wheels from receiving a sudden change in force as a lower gear is selected and road speed doesn't match engine speed.
The word 'sympathy' is very deliberate. You are not going to break your car or crash if you fail to rev-match when driving on the public road at a sensible speed (although you may have a scary moment in the wet in a Caterham, TVR or similar). The thing is, no aspect of car control taught in advanced road driving will result in you actually crashing if you fail to do it. Similarly roadcraft elements such as signalling, showing brake lights, positioning your car to see and be seen, etc - they are all layers of safety that build up, such that if one is lost you're still ok. Personally, I continue to do all of the above because I like as many layers as possible. Personally I've not let the clutch out after a downchange without rev-matching since about a week after I passed my test; I just wouldn't consider it.
RobM77 said:
Forgive me if I've mis-understood you, but the point of rev matching is twofold:
The word 'sympathy' is very deliberate. You are not going to break your car or crash if you fail to rev-match when driving on the public road at a sensible speed (although you may have a scary moment in the wet in a Caterham, TVR or similar). The thing is, no aspect of car control taught in advanced road driving will result in you actually crashing if you fail to do it. Similarly roadcraft elements such as signalling, showing brake lights, positioning your car to see and be seen, etc - they are all layers of safety that build up, such that if one is lost you're still ok. Personally, I continue to do all of the above because I like as many layers as possible. Personally I've not let the clutch out after a downchange without rev-matching since about a week after I passed my test; I just wouldn't consider it.
huge parrot Rob.- Mechanical sympathy: Rev matching prevents the clutch and gearbox from receiving a sudden load if the speeds of one side and the other aren't the same and then are suddenly brought together by the clutch.
- Dynamic sympathy: Rev matching prevents the driven wheels from receiving a sudden change in force as a lower gear is selected and road speed doesn't match engine speed.
The word 'sympathy' is very deliberate. You are not going to break your car or crash if you fail to rev-match when driving on the public road at a sensible speed (although you may have a scary moment in the wet in a Caterham, TVR or similar). The thing is, no aspect of car control taught in advanced road driving will result in you actually crashing if you fail to do it. Similarly roadcraft elements such as signalling, showing brake lights, positioning your car to see and be seen, etc - they are all layers of safety that build up, such that if one is lost you're still ok. Personally, I continue to do all of the above because I like as many layers as possible. Personally I've not let the clutch out after a downchange without rev-matching since about a week after I passed my test; I just wouldn't consider it.
as per thread, "auto"
Peter3442 said:
Much as enjoy the fun of controlling things myself, I wonder if, at some time in the distant past, people were having the same kind of discussion about the advance-retard lever?
It's an often quoted analogy. However, having driven cars with and without a manual advance/retard lever, I view it almost like a manual choke, so not a primary control, just an element of engine setup. For me, the joy of driving is all about the phases of a corner (start of braking, middle braking, pre-turn in, turn-in, pre apex phase, apex, post apex, and exit), and I wouldn't use such a lever during any of those phases. Rev-matching, on the other hand, applies in the first two, and in some complex corners can apply in later phases too.RobM77 said:
It's an often quoted analogy. However, having driven cars with and without a manual advance/retard lever, I view it almost like a manual choke, so not a primary control, just an element of engine setup. For me, the joy of driving is all about the phases of a corner (start of braking, middle braking, pre-turn in, turn-in, pre apex phase, apex, post apex, and exit), and I wouldn't use such a lever during any of those phases. Rev-matching, on the other hand, applies in the first two, and in some complex corners can apply in later phases too.
exactly.a better analogy is horses. they used to be a means of transportation but became redundant and are now an expensive hobby.
Cars with clutches, steep power curves, driver operated steering but no torque vectoring are becoming redundant and are an expensive hobby.
CABC said:
RobM77 said:
It's an often quoted analogy. However, having driven cars with and without a manual advance/retard lever, I view it almost like a manual choke, so not a primary control, just an element of engine setup. For me, the joy of driving is all about the phases of a corner (start of braking, middle braking, pre-turn in, turn-in, pre apex phase, apex, post apex, and exit), and I wouldn't use such a lever during any of those phases. Rev-matching, on the other hand, applies in the first two, and in some complex corners can apply in later phases too.
exactly.a better analogy is horses. they used to be a means of transportation but became redundant and are now an expensive hobby.
Cars with clutches, steep power curves, driver operated steering but no torque vectoring are becoming redundant and are an expensive hobby.
I used to ride horses and I agree - that's a good analogy. I like driving in the same way that I enjoyed horse riding in my youth and now enjoy cycling or windsurfing. If I was to use one of those sports as a means of transport, as I used to for cycling, I would still enjoy it in exactly the same way. I wouldn't suddenly back right off and want an upright commuter bike just cause I was cycling to work; I used to ride my road bike to work and chase Strava segments just as I do at weekends.So, back to rev matching - when I drive to work I rev match every gearchange and enjoy that whole process of driving. I don't want a computer doing it for me. The only things I'm happy leaving to a computer are things like DSC or ABS, because for safety reasons they're outside the realm of what I do on the public road.
RobM77 said:
I used to ride horses and I agree - that's a good analogy. I like driving in the same way that I enjoyed horse riding in my youth and now enjoy cycling or windsurfing. If I was to use one of those sports as a means of transport, as I used to for cycling, I would still enjoy it in exactly the same way. I wouldn't suddenly back right off and want an upright commuter bike just cause I was cycling to work; I used to ride my road bike to work and chase Strava segments just as I do at weekends.So, back to rev matching - when I drive to work I rev match every gearchange and enjoy that whole process of driving. I don't want a computer doing it for me. The only things I'm happy leaving to a computer are things like DSC or ABS, because for safety reasons they're outside the realm of what I do on the public road.
.
I think another advantage when using (learning) an advanced technique like H&T all the time, it becomes second nature, allows a lot more practice because you are doing it more, and perhaps what better way to learn than at a slower pace. Most good drivers will have developed a system which is used all the time, which makes for a very consistent level – when other cars are around me, an assessment of their consistent driving provides me with quite an accurate level of their driving skill, and generally make bigger allowance for those all over the place.
Apart from ABS and DSC (which have not been activated in years) I drive with all these aids off as I do not like them. When auto wipers came out I thought they were great as the wipers would be matched to the correct speed for conditions, however having them turn on automatically does not work for me.
Can remember driving home in very bad conditions, in the dark – it was not raining but the roads were very wet causing a lot of spray, the auto wipe was working well, but just when another car was approaching with bright lights, the screen had a nice film of dirt, and yes auto wipe decided to start, resulting in no forward vision. If I keep auto wipe turned off, using the manual control is a skill I keep and use so much that it becomes second nature. Same with auto light – I do not want headlights coming on at an inappropriate moment which could confuse another road user.
My TVR is open top, quite loud and a couple of times had left the turn signal running because it had not self cancelled, in bright light could not see the warning light, or hear the clicking. I disabled the self cancelling – It has become second nature to manually cancel and have not had this problem since.
Think IMHO all these auto things added just dumb down driver instinct, and take away skill and responsibility to be a good, safe driver.
Thanks to this thread, I paid attention to my rev matching the last couple of days and found that I do it automatically. In fact so automatically, that I'm not at all sure how my brain makes all the judgements. It's difficult not to do it. If I don't get it right, I feel as foolish as if I'd driven off with the handbrake on. Have I been driving too many years?
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