Just switched to an 8speed Auto, feel like I need training

[SOL111]

RobM77 said:

That's interesting. Obviously its not ideal to be changing gear during turn in, so I wondered if there was a reason you need to drive the auto like that? If you're braking and want to, for example, go from 3k rpm in 4th gear to 4k rpm in 3rd during braking, so that you arrive at turn in a short time later at 3,500rpm in 3rd, can you do that with the ZF or will it block you, forcing you to do it later when the revs are lower?

The reason for me asking is that I'm toying with the idea of changing from a 3 series to a 5 series for my next car, and the main negative factor is the lack of manual gearboxes in them (I tow regularly, so ideally want more power than the 520d offers). My commute is almost entirely bumpy and twisty B and A roads.

Hi Rob

Apologies if I made it sound like I was changing during turn in. What I meant was that I'd wipe off the necessary speed (on the straight) and then change down before entering the bend. It's just that I'd learnt to do it before the car decided to.

In your example, if the engine is at 3k rpm then you wouldn't have an issue and you'd still have 100% control over gear selection. It's just that for tight bends, where you might wipe off a lot of speed, then you'd end up hovering around 1k rpm and the auto would drop you down the necessary gears. If you're not anticipating this auto down shift then it can be a problem as you'd then manually shift down again, leaving you in too low a gear.

I hope that makes sense so apologies again if not.

To be honest it's only an issue about 2% of the time. Otherwise I'd say the ZF is faultless and is as good a manual as it gets (for an auto). I think in short, the ZF will allow you to redline (I think except for 'S' mode) but will automatically change down if the revs fall below 1k rpm.

Hope this helps.

[BeastMaster]

Would just like to add my recent experience of going to auto.

Wanted a BMW 420 D M-sport, for use as work and daily driver, always had a manual as my only drive in an auto was a from a hire company which only had an auto available which was the old school slush box – and hated it

I also own and drive for fun a TVR Chimaera 500 and a Boxster S both manual.

Found the BMW I wanted – 2.5 years old, in the right colour, manual with M-Sport pack and went to view it – very disappointed as it had had a very hard life with no love, on the way out spotted another 420 D which was inside the showroom and had just come in – was immaculate and everything I wanted except it was 8 speed auto and four wheel drive.

Long story short, ended up buying it after a test drive, and love it.

The M sport button has 4 settings, eco pro, comfort, sport and sport plus each programmable through the I-Drive, the auto box being controlled by the computer, the gear selector or paddles behind the steering wheel.

As the OP, I was concerned that I would become another driver who is constantly on the brakes, whether motorway, fast road or in town would be on the middle pedal most of the time, something my years of driving instinct tells me is not right.

After 6 months and 20k miles am still delighted with the overall auto experience, it is very, very good what ever mode you want to drive in. Engine braking for such a heavy car is acceptable, do not need to be on and off the brakes for every little change in speed, and never feel out of the control loop. When rapid progress is required the sport plus provides an aggressive upshift and keeps things much more on the boil, the paddle shifters allow for either total manual control, or to just override a moment in the auto setting, say when you wish for an early up or downshift to set the car up for a corner or anticipate an overtake.

In conclusion the 2 things, 4 wheel drive and auto which I have always hated because they add weight and take away dynamic driving experience have come a long way in recent years, and will not hesitate when retirement requires a replacement for the TVR and Boxster – perhaps Carrera 4S auto

[LunarOne]

As you've not mentioned XDrive, I'll assume your BMW is RWD. I can't imagine why you'd want to go round doing most of your braking with just two tyres, especially two in the rear, which is what you're doing by using engine braking. Slowing down involves weight transfer to the front wheels, therefore unloading the rear wheels. Therefore, your rear wheels have much less stopping power than your front wheels, which is why many cars have much larger brakes at the front than the rear. If you're doing this in a straight line, it's not too much of a problem as long as adequate grip is available, but if you do this in a bend you are upsetting the balance of the car and potentially inciting an oversteer moment. In addition, you're introducing reverse loading throughout the drivetrain, which in time increases lash (slop) and can cause a gearbox to lose smoothness.

You'd especially want to avoid engine braking in slippery conditions, where braking only one end of the car can cause sudden loss of control. Can you imagine navigating a chicane in slippery conditions using only your handbrake? I'm sure you can.

Sure, engine braking has its uses. In very sporty driving when using low gears and high revs, it allows fine control of progress without the need to move the right foot off the accelerator and onto the brake pedal. That's useful when racing when you're in a tight pack inches off the rear bumper of the car in front of you. But in normal driving it's also useful during long hill or mountain descents when you'd otherwise need to risk overheating your brakes in order to maintain or reduce speed. Engine braking allows you to use the brakes intermittently, allowing them to cool between each application.

In other cases, it's much preferable to use the brakes to reduce speed. The brakes offer much more braking power with greatly reduced risk of upsetting the balance of the car. They also offer the ability to modulate braking action from just a slight retardation to full wheel locking. They reduce wear on the transmission, and as is often stated, brake pads are so cheap and easy to swap that it doesn't take more than a minute or two per wheel for some caliper designs.

Now I haven't mentioned the fun factor yet. There's something quite intoxicating about a perfect rev-match, jumping into a lower gear and listening to the exhaust popping and banging away as the car decelerates. My Porsche with 6-speed manual, sports exhaust and sport chrono package does a perfect rev-match followed by the symphony of crazy exhaust action with every gear change; I don't even need to touch the accelerator pedal. But that's all about flamboyant driving and has little to do with slowing the car under control by itself. Indeed, its best use is to free my right foot to work the brakes while I change gear. Again not the usual system, but fun during very spirited driving. No need for any heel and toe work that I still practice on my old manual BMW!

[xjay1337]

[quote=LunarOne My Porsche with 6-speed manual, sports exhaust and sport chrono package ...
[/quote]

Don't come round to my house for dinner.

[LunarOne]

xjay1337 said:

Don't come round to my house for dinner.

Your wish is my command!

[BeastMaster]

LunarOne said:

As you've not mentioned XDrive, I'll assume your BMW is RWD. I can't imagine why you'd want to go round doing most of your braking with just two tyres, especially two in the rear, which is what you're doing by using engine braking. Slowing down involves weight transfer to the front wheels, therefore unloading the rear wheels. Therefore, your rear wheels have much less stopping power than your front wheels, which is why many cars have much larger brakes at the front than the rear. If you're doing this in a straight line, it's not too much of a problem as long as adequate grip is available, but if you do this in a bend you are upsetting the balance of the car and potentially inciting an oversteer moment. In addition, you're introducing reverse loading throughout the drivetrain, which in time increases lash (slop) and can cause a gearbox to lose smoothness.

You'd especially want to avoid engine braking in slippery conditions, where braking only one end of the car can cause sudden loss of control. Can you imagine navigating a chicane in slippery conditions using only your handbrake? I'm sure you can.

Sure, engine braking has its uses. In very sporty driving when using low gears and high revs, it allows fine control of progress without the need to move the right foot off the accelerator and onto the brake pedal. That's useful when racing when you're in a tight pack inches off the rear bumper of the car in front of you. But in normal driving it's also useful during long hill or mountain descents when you'd otherwise need to risk overheating your brakes in order to maintain or reduce speed. Engine braking allows you to use the brakes intermittently, allowing them to cool between each application.

In other cases, it's much preferable to use the brakes to reduce speed. The brakes offer much more braking power with greatly reduced risk of upsetting the balance of the car. They also offer the ability to modulate braking action from just a slight retardation to full wheel locking. They reduce wear on the transmission, and as is often stated, brake pads are so cheap and easy to swap that it doesn't take more than a minute or two per wheel for some caliper designs.

Now I haven't mentioned the fun factor yet. There's something quite intoxicating about a perfect rev-match, jumping into a lower gear and listening to the exhaust popping and banging away as the car decelerates. My Porsche with 6-speed manual, sports exhaust and sport chrono package does a perfect rev-match followed by the symphony of crazy exhaust action with every gear change; I don't even need to touch the accelerator pedal. But that's all about flamboyant driving and has little to do with slowing the car under control by itself. Indeed, its best use is to free my right foot to work the brakes while I change gear. Again not the usual system, but fun during very spirited driving. No need for any heel and toe work that I still practice on my old manual BMW!

Hi Alex

Hi Alex

Yes in fact the BMW is X Drive so 4 wheel drive, albeit with 60% drive to the rear. The point I wanted to make was that I also was concerned that auto box would give no engine braking whatsoever, and would just coast when lifting off, but this is not the case at all – in auto mode when lifting off engine braking is felt and is useful in controlling small changes in speed, in fact the auto mode will change down as speed is scrubbed off – if BMW had thought this was bad I think they would not have designed such a programme into the ECU.

I except what you are saying about using engine braking alone is not correct, as this would require quite extreme use of the gear box to slow the car, but engine braking is always going to be present and must be considered – I don’t think you are suggesting dipping the clutch and using the brakes alone.

It is quite difficult to see how typical road car would have the engine torque to give problems unless being abused by changing down way to early and dropping the clutch.

As you said, in your post – if in a straight line not too much of a problem, but this is the only real safe way to drive – all of your braking, gear changing on the straight, get the right speed and in the right gear before entering the corner – then use the throttle to balance the car in the corner, upon exiting accelerate back up to safe speed. So yes their will be a change down during the braking phase so as to be in the correct gear for the corner - otherwise a gear change mid corner would be required,

[BertBert]

You don't have to change gear during the brake phase. Do it after braking before adding steering lock.
Bert

[BeastMaster]

BertBert said:

You don't have to change gear during the brake phase. Do it after braking before adding steering lock.
Bert

Hiya

It is quite advantageous to be trail braking during initial steer into a corner, this provides more weight over the front wheels which aids grip, If driving my TVR, a very light car with limited slip diff this is quite essential other wise the car will not want to turn in. In the Auto BMW in auto mode, during the braking phase the ECU will auto change down - as I said if this was bad why would BMW allow this.

[dvenman]

BertBert said:

You don't have to change gear during the brake phase. Do it after braking before adding steering lock.
Bert

The auto will decide for itself, no ? On a manual, I may heel and toe to compress the system and maintain a little more speed - changing gear on a manual during braking I don't like except in very specific circumstances as I can't get it smooth and it'll upsect the balance of the car.

[RobM77]

BeastMaster said:

BertBert said:

You don't have to change gear during the brake phase. Do it after braking before adding steering lock.
Bert

Hiya

It is quite advantageous to be trail braking during initial steer into a corner, this provides more weight over the front wheels which aids grip, If driving my TVR, a very light car with limited slip diff this is quite essential other wise the car will not want to turn in. In the Auto BMW in auto mode, during the braking phase the ECU will auto change down - as I said if this was bad why would BMW allow this.

I've had this argument on here before Everyone seems to like turning in with an unloaded front end.

[waremark]

RobM77 said:

BeastMaster said:

BertBert said:

You don't have to change gear during the brake phase. Do it after braking before adding steering lock.
Bert

Hiya

It is quite advantageous to be trail braking during initial steer into a corner, this provides more weight over the front wheels which aids grip, If driving my TVR, a very light car with limited slip diff this is quite essential other wise the car will not want to turn in. In the Auto BMW in auto mode, during the braking phase the ECU will auto change down - as I said if this was bad why would BMW allow this.

I've had this argument on here before Everyone seems to like turning in with an unloaded front end.

Yes indeed! We think that on the road you should be far enough away from the limit of grip that any car will turn in fine with the weight evenly balanced front to back. Completing the braking before turn-in has the advantage on unsighted bends (like the majority in England) that the speed is lowest where the vision is shortest - which is before you start to turn.

The question of whether to brake into the bend is quite separate from whether to overlap brakes and gear change. The system of driving recommended by the main advanced driving organisations requires completion of the braking phase before the gear change phase. Advantages of this are that in a manual car the right foot is available for rev matching without needing to heel and toe, that braking earlier adds additional safety, and that the driver only has to do one thing at a time. The disadvantages are that it is slower (you have to brake earlier than would otherwise be required if a gearchange is anticipated), that by braking earlier you are braking with less information about the bend, and that slowing earlier may not meet the expectations of following traffic. I must admit that I now generally overlap using heel and toe if driving at all progressively.

[RobM77]

waremark said:

RobM77 said:

BeastMaster said:

BertBert said:

You don't have to change gear during the brake phase. Do it after braking before adding steering lock.
Bert

Hiya

It is quite advantageous to be trail braking during initial steer into a corner, this provides more weight over the front wheels which aids grip, If driving my TVR, a very light car with limited slip diff this is quite essential other wise the car will not want to turn in. In the Auto BMW in auto mode, during the braking phase the ECU will auto change down - as I said if this was bad why would BMW allow this.

I've had this argument on here before Everyone seems to like turning in with an unloaded front end.

Yes indeed! We think that on the road you should be far enough away from the limit of grip that any car will turn in fine with the weight evenly balanced front to back. Completing the braking before turn-in has the advantage on unsighted bends (like the majority in England) that the speed is lowest where the vision is shortest - which is before you start to turn.

The question of whether to brake into the bend is quite separate from whether to overlap brakes and gear change. The system of driving recommended by the main advanced driving organisations requires completion of the braking phase before the gear change phase. Advantages of this are that in a manual car the right foot is available for rev matching without needing to heel and toe, that braking earlier adds additional safety, and that the driver only has to do one thing at a time. The disadvantages are that it is slower (you have to brake earlier than would otherwise be required if a gearchange is anticipated), that by braking earlier you are braking with less information about the bend, and that slowing earlier may not meet the expectations of following traffic. I must admit that I now generally overlap using heel and toe if driving at all progressively.

As ever, thanks for your input Mark. As you know I respect your driving greatly. Yes, it's linked in with H&T. I guess I (and others) are a bit of a different case, because we've used heel and toe for so long that it's second nature (I grew up in a family that owned a few 1930s cars, so I learnt the week after I passed my test); 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!). If taking a new driver and putting them through a syllabus, there are many more things of greater importance to teach them.

The point you make regarding how far one is from the limit is a good one, but I would extend it and say "if it doesn't matter, then why steer smoothly?" or "if it doesn't matter, then why rev match?". I see transitioning closer towards the limit of adhesion, even momentarily, to be unnecessary, so I try not to do it. I actually use pretty much all the same car control techniques that I use on track on the road for this reason, but obviously at a much lower speed to give a safety margin. Probably the most important one is sensory: knowing where the limit is and how it changes according to the road surface, temperature, tyres etc. Even though I give a safety margin, I still drive a little slower if there's less grip available on a particular corner.

[BeastMaster]

dvenman said:

The auto will decide for itself, no ? On a manual, I may heel and toe to compress the system and maintain a little more speed - changing gear on a manual during braking I don't like except in very specific circumstances as I can't get it smooth and it'll upsect the balance of the car.

Yes of course the auto decides for itself - that's what I said did I not.

But everyone is saying how bad it is to change down, in your words (changing gear on a manual during braking I don't like) so why does BMW allow their auto box to downshift during the braking phase if it is so bad.

Or perhaps the reality is that it takes practice to gain the skill of heel and toe to downshift during the braking phase, a skill which is obviously not mastered by most - in your words (as I can't get it smooth and it'll upset the balance )

And please do not say an auto box is smoother which is why it is allowed to change down, because that is not true and any good driver would be equal or maybe better at rev matching than a normal auto box - in sport mode it is quite harsh.

SO SOMEONE PLEASE TELL ME IF IT IS SO BAD WHY DOES MY AUTO BOX DOWNSHIFT DURING BRAKING, - if you can give me a real reason I will sue BMW for manufacturing a car which will kill me !!!!!!

[RobM77]

BeastMaster said:

dvenman said:

The auto will decide for itself, no ? On a manual, I may heel and toe to compress the system and maintain a little more speed - changing gear on a manual during braking I don't like except in very specific circumstances as I can't get it smooth and it'll upsect the balance of the car.

Yes of course the auto decides for itself - that's what I said did I not.

But everyone is saying how bad it is to change down, in your words (changing gear on a manual during braking I don't like) so why does BMW allow their auto box to downshift during the braking phase if it is so bad.

Or perhaps the reality is that it takes practice to gain the skill of heel and toe to downshift during the braking phase, a skill which is obviously not mastered by most - in your words (as I can't get it smooth and it'll upset the balance )

And please do not say an auto box is smoother which is why it is allowed to change down, because that is not true and any good driver would be equal or maybe better at rev matching than a normal auto box - in sport mode it is quite harsh.

SO SOMEONE PLEASE TELL ME IF IT IS SO BAD WHY DOES MY AUTO BOX DOWNSHIFT DURING BRAKING, - if you can give me a real reason I will sue BMW for manufacturing a car which will kill me !!!!!!

I'm talking theoretically here, because whilst I have driven a few autos on track, it's not been many and not for very long. Obviously, as you say, a downchange means an increase in revs, and that is put through the drivetrain to the wheels as a change in engine braking. So if you've set your braking to a particular level, this level will be changed by the braking. One difference with an automatic is that the torque converter will smooth out this change a lot, so it won't be spiky, as it would be if you downshifted in a manual car without rev matching. Spikiness matters because of the shape of the slip/grip curve, which means that a short sharp input will much more easily result in a slide than a smooth input of the same magnitude. This means you are less likely to lock up the driven wheels if braking on threshold without a rev match with a torque converter than you would be with a manual, but I still would have thought you're still more likely to come unstuck than a skilled driver heel and toeing. Let's also not forget that the car will have ABS and DSC, so you won't actually lock up, you may just have you maximum retardation rate decreased a little. On that note, it would be a good idea for the car to detect an emergency stop and deal with downchanges differently actually - perhaps they do that? Perhaps performance autos rev match? I've certainly heard some do it, but perhaps they were DSC, not TC autos?

[BertBert]

BeastMaster said:

Hiya

It is quite advantageous to be trail braking during initial steer into a corner, this provides more weight over the front wheels which aids grip, If driving my TVR, a very light car with limited slip diff this is quite essential other wise the car will not want to turn in. In the Auto BMW in auto mode, during the braking phase the ECU will auto change down - as I said if this was bad why would BMW allow this.

You don't have to be driving to the limit on the road. In fact if you need the front end loaded to get your TVR to turn a corner you are driving too quickly. You are absolutely a hostage to fortune.
Bert

[BeastMaster]

BertBert said:

You don't have to be driving to the limit on the road. In fact if you need the front end loaded to get your TVR to turn a corner you are driving too quickly. You are absolutely a hostage to fortune.
Bert

Bert – you are totally wrong in two ways
.
First off, knowing nothing about me, you have assumed as many that I am some kind of hooligan who should be locked up because I drive a loud, powerful in your face car. In fact I have 47 years behind the wheel experience, never had an accident, and have no points on my licence.

Secondly, my TVR is old school, having no driver aids to corrupt, it rewards good driving like nothing else as well as it punishes if you do not drive well.

My driving satisfaction comes from not exploring the max limits that can be achieved, but from driving the very best I can, using a system which has kept me in good stance over my years on the road. That system has become second nature and use it whenever behind the wheel, parking in Tesco’s or making progress on a fast B road the system works for me.

I think this is the problem with the masses today, having an attitude of I am not driving on the limit so driving technique does not apply to me, an attitude also to all things car related – ‘ I never drive at the limit so my tyres will only need replacing at the legal requirement ‘

The whole point about good driving, and having pride in ability is to provide the largest margin of safety possible, I do not need to be at the limit to use trail braking to aide turn in, I am rewarded by having a better balance and steering feel, even at quite sedate speeds, and also have a responsive car, should avoiding action be required.

Good technique and attitude should be engaged all the time, not just when making progress, only then does it become second nature, otherwise the whole standard will drop – perhaps this is why no one indicates intention any more – because ‘ I am only crawling around this roundabout in the middle of other users I do not need to indicate my exit ‘ is poor excuse.

[S. Gonzales Esq.]

BeastMaster said:

... I do not need to be at the limit to use trail braking to aide turn in, I am rewarded by having a better balance and steering feel, even at quite sedate speeds ...

Amen to that - once you've learned how to notice the subtleties of a vehicle's balance, thoughtful use of weight transfer can make a massive difference to the smoothness of a drive. The sensation of merely guiding the steering, rather than wrestling it around a corner against its will, is addictive.

One thing though - I've seen people get so reliant on the comfort of trail braking that they'll use it even in bends where the view has already opened, losing a lot of potential progress as a result.

[dvenman]

BeastMaster said:

SO SOMEONE PLEASE TELL ME IF IT IS SO BAD WHY DOES MY AUTO BOX DOWNSHIFT DURING BRAKING, - if you can give me a real reason I will sue BMW for manufacturing a car which will kill me !!!!!!

It's not the downshifting per se, it's the possibility of upsetting the balance and dynamics of the car when it's being asked to do other things than going in a straight line, and if you're close to the limit has the potential to make things quite interesting.

[BertBert]

BeastMaster said:

BertBert said:

You don't have to be driving to the limit on the road. In fact if you need the front end loaded to get your TVR to turn a corner you are driving too quickly. You are absolutely a hostage to fortune.
Bert

Bert – you are totally wrong in two ways
.
First off, knowing nothing about me, you have assumed as many that I am some kind of hooligan who should be locked up because I drive a loud, powerful in your face car. In fact I have 47 years behind the wheel experience, never had an accident, and have no points on my licence.

Secondly, my TVR is old school, having no driver aids to corrupt, it rewards good driving like nothing else as well as it punishes if you do not drive well.

My driving satisfaction comes from not exploring the max limits that can be achieved, but from driving the very best I can, using a system which has kept me in good stance over my years on the road. That system has become second nature and use it whenever behind the wheel, parking in Tesco’s or making progress on a fast B road the system works for me.

I think this is the problem with the masses today, having an attitude of I am not driving on the limit so driving technique does not apply to me, an attitude also to all things car related – ‘ I never drive at the limit so my tyres will only need replacing at the legal requirement ‘

The whole point about good driving, and having pride in ability is to provide the largest margin of safety possible, I do not need to be at the limit to use trail braking to aide turn in, I am rewarded by having a better balance and steering feel, even at quite sedate speeds, and also have a responsive car, should avoiding action be required.

Good technique and attitude should be engaged all the time, not just when making progress, only then does it become second nature, otherwise the whole standard will drop – perhaps this is why no one indicates intention any more – because ‘ I am only crawling around this roundabout in the middle of other users I do not need to indicate my exit ‘ is poor excuse.

Tetchy Sorry to have disturbed your equilibrium, wasn't my intention. So answering in seriousness for the purposes of debate. I think you are incorrect as to whether you are on the limit or not and here's why.

BeastMaster said:

this is quite essential other wise the car will not want to turn in.

So if you are not loading the front and it does what you say, ie it will not want to turn in, then I assume that it is understeering. If so, then it can only be doing it because it does not have enough grip at the front. Ie it is on the limit of grip. So I am not wrong. In those circumstances I would maintain you are driving to the limit. If as you say, your techniques have to be engaged all the time (are you sure?), then in your Trevor you must be understeering everywhere. I'm not sure I read about that in Roadcraft. Perhaps I am being too literal

Obviously it's a matter of degree, but the problem you've got if you are countering turn in understeer with braking effort is... if the level of grip reduces your choices are pretty limited. You can't lift off (for obvious reasons) to quell the understeer, you can't put on more lock, you have to unwind the steering. Perhaps you have anticipated the possible need for more road to control the situation.

Bert

[Haltamer]

Non-limit trail braking could (And perhaps should) be a thread of it's own.

I've generally avoided trail braking intentionally; given the non-systematic nature - However, especially on closed corners I can see the benefit in turn in, braking reactions should a hazard arise, as well as balancing the vehicle and managing the weight transfer, even if you've overdone it a tad and entered too fast to hold on the throttle