M5 Power Delivery - help from BMW requested

[SteveC]

Hi M6-Coupe, that was very kind of you to go to the trouble to make that video. Most appreciated What your video illustrates are unrestrained down shifts in response to small divisions on the gas pedal.

I'm taking my car out this morning for a long drive on quiet roads. I'll try to reproduce exactly what your video illustrates

[SteveC]

Originally Posted by M6-Coupe

Steve,
Your "MANUAL DCT" in D mode needs your right foot instead of right hand (your left hand) to shift the gear.
Underneath your right foot you have room and you need to use that room to instruct this manual gearbox downshift for you even in D1.
Driving at 50 mph, D1, Efficient, 1200 RPM, if you divide that room by 4 then,
Push the gas pedal to 1/4 and DCT downshifts to 6th gear.
Or push the gas pedal harder to 1/2 and DCT downshifts to 5th gear.
Or push the gas pedal much harder to 3/4 and DCT downshifts to 4th gear.
Or Push the gas pedal to floor (pass the kickdown) and DCT downshifts to 3th gear.
I took the video for you to show how

Well I tried to reproduce what you illustrated in your video, a nice, linear progressive set of down shifts. My results:

At 1/4 throttle DCT ignores my input and stays in 7th
At 1/2 throttle it still isn't paying attention, so 7th
At 3/4 I get 6th and very quickly thereafter 5th
On the floor I get 4th at ca. 3000 rpm

If I avoid 7th and try the same exercise beginning in 6th I get exactly what you illustrate....a progressive set of downshifts, down to third at full taps

Its exactly as I've said from the beginning....the car is great until it gets to 7th then it kinda checks out and forgets its an M5. Before it shifts to 7th, there's always a delay where it makes sure I'm at a steady speed before selecting overdrive. But once its in overdrive it doesn't like to let go. In my opinion, it only selects 7th when its sure overdrive is appropriate....it should apply the same logic and get out of overdrive when it sees the driver would like to accelerate, instead of doggedly hanging on to it at 1200 rpm.

I started the test after some very sporty driving so should have started from a sport map, depending on how the adaptive mapping works

[Dionysus]

Originally Posted by RPiM5

Running a straightpipe exhaust requires me to keep the RPM's down for sound level decibel reasons. I'm not sure how it is in the UK.

D - from my experience, even the MPE/Akra in D3/Sport+ draws at lot of unwanted attention in UK. I've no idea how the likes of mstmng has lasted this long. I must be doing something wrong!

Originally Posted by M6-Coupe

Steve,
Driving at 50 mph, D1, Efficient, 1200 RPM

Great video M6-Coupe

Originally Posted by SteveC

If I avoid 7th and try the same exercise beginning in 6th I get exactly what you illustrate....a progressive set of downshifts, down to third at full taps

I started the test after some very sporty driving so should have started from a sport map, depending on how the adaptive mapping works

Question - assuming a controlled testing regime (same prior driving style, same stretch of road, same environmental conditions, etc.), how did you get your car to start the first test in 7th and the second test in 6th... ?

Originally Posted by SteveC

Is it possible that the adaptive gearbox learns this more relaxed driving style and hangs onto it for a while?

My car does seem to remember previous driving style as long as I drive it on a weekly basis. Not long after I start driving faster, but still in D1/Efficient, the responses quicken. If I then momentarily slow from say 70mph to 50mph, acceleration is entirely progressive/linear when returning to 70mph. Only after I've driven for an extended period at 1200revs in 7th does my car become lazy. From this point it then remains in 7th with a switch to D3/Sport+ and has a three step response to WOT; within a couple of seconds - (1) pause, (2) reasonable acceleration, (3) excessive acceleration, i.e. nothing progressive/linear.

Driven in what I consider it's natural environment (high speed German autobahn cruising), I do not believe this lazy behaviour would occur.

The only time my car didn't do this is immediately after the MPE was fitted and the ECU was still adjusting. Even with gentle driving it was intermittently holding on low gears in D1/Efficient for a short period of time.

[bluekn8286]

My e92 M3 does the exact same thing when the shift timing is set to 3; if you increase it to 5, it kicks down gears super duper quickly and the car wakes up.

[SteveC]

Originally Posted by Dionysus

Question - assuming a controlled testing regime (same prior driving style, same stretch of road, same environmental conditions, etc.), how did you get your car to start the first test in 7th and the second test in 6th... ?

That's easy.......accelerate to 60 mph through the gears and the car stays in 6th for a while until it sees you're at steady speed, at which point it drops into 7th (overdrive).

For testing in 6th, just accelerate gently to 60, hold briefly, then from 6th gear, give 1/4 throttle and so on. For 7th, accelerate to 60, hold at steady speed until 7th is selected, hold a while longer in 7th, then give 1/4 throttle.

Originally Posted by Dionysus

Driven in what I consider it's natural environment (high speed German autobahn cruising), I do not believe this lazy behaviour would occur.

My car isn't a problem at higher speeds (say 80 mph) because even in 7th there's plenty of torque and acceleration, whereas at 50 (ca. 1200rpm) there's no torque and the turbos are idling, so no acceleration.

Originally Posted by Dionysus

Only after I've driven for an extended period at 1200revs in 7th does my car become lazy. From this point it then remains in 7th with a switch to D3/Sport+ and has a three step response to WOT; within a couple of seconds - (1) pause, (2) reasonable acceleration, (3) excessive acceleration, i.e. nothing progressive/linear.

Afraid I didn't understand this. Are you saying your car gets very lazy and holds 7th only after extended slow 1200rpm driving.....because that's when I think I have the problem. Follow a slowish car for several miles, then get a short straight, give it some beans and ............more beans and ............loads of beans..oops....run out of road

[SteveC]

When the Germans talk about shift timing....are they talking about how quickly the car actually takes to shift....i.e 200ms, 100ms, 80 ms or are they talking about how 'quickly' it shifts for a given amount of throttle i.e 1/4 throttle, 1/2 throttle, 3/4 throttle

If you say, "my car shifts very quickly" it could mean that the shift itself is very fast or that the car shifts very quickly when given some throttle.

Does selecting 3 give you much faster shifts or is it that the car shifts more readily i.e becomes more sensitive to the gas pedal?

Given that my BMW Dealer's resident Genius told me it adjusted the amount of turbo boost, I wonder if I have hold of the wrong end of the stick. I've always understood that it adjust the speed of the shift, but it could be that it adjusts the 'point' of the shift.

[Bönz]

Technically speaking, both 6th and 7th gear are overdrive.

In D mode, the MDCT setting affects both the shift point (when the transmission shifts) and shift speed (the time it takes to swap gears, measured in milliseconds). The MDCT setting is just one input of many that determines shift point. Obviously in setting D1, it will shift sooner and hold onto higher gears, even to the aggravation of some owners.

In S mode, since the driver is responsive for the shift point, the setting only affects shift speed. It has no affect on turbo boost.

[DrewM5]

Guys, this is futile. He is going to think what he wants to think and has shown quite clearly that he either has no desire or no capacity to understand what he is being told.

[Wills2]

Originally Posted by DrewM5

Guys, this is futile. He is going to think what he wants to think and has shown quite clearly that he either has no desire or no capacity to understand what he is being told.

Amen to that.

[SteveC]

Originally Posted by DrewM5

Guys, this is futile. He is going to think what he wants to think and has shown quite clearly that he either has no desire or no capacity to understand what he is being told.

Desire.

And yes, it is futile. I still can't quite swallow that with all the performance and everything the M5 has to offer, that in certain circumstances, the M135i was more fun to drive and felt the more capable car. Especially when the shortcoming is down to transmission programming and I need workarounds to make the M5 perform.....in certain circumstances.

[M6-Coupe]

F87 M2

[mstmng]

Originally Posted by Dionysus

D - from my experience, even the MPE/Akra in D3/Sport+ draws at lot of unwanted attention in UK. I've no idea how the likes of mstmng has lasted this long. I must be doing something wrong!

i have no problem

i got used to it, i was tired of cold start and that did piss some people off, however i have finally gotten rid of it
my car is little mouse compared to straight-piped aventadors around london, plus its good when people can hear you coming, they are more likely to check their mirrors before doing any stupid manoeuvre

[Dionysus]

Originally Posted by M6-Coupe

F87 M2

Agreed, although if losing the rear doors, I'd rather go further and opt for more analogue experience such as 981 Cayman, etc...

Originally Posted by mstmng

my car is little mouse compared to straight-piped aventadors around london

I'm going to have to make an effort to visit during the 'season' to hear some of these; the sound must be wonderfully insane!

[SteveC]

Originally Posted by Dionysus

Agreed, although if losing the rear doors, I'd rather go further and opt for more analogue experience such as 981 Cayman, etc...

GT4......MMmmmm

Originally Posted by Dionysus

I'm going to have to make an effort to visit during the 'season' to hear some of these; the sound must be wonderfully insane!

Try Singapore if you want exotic sounds. Sunday 2am in a downtown hotel....the traffic light GPs were amazing....sometimes three exotics gunning it to the next red light. Worth getting out of bed...if only for the exhaust flames

[Dionysus]

Originally Posted by SteveC

GT4......MMmmmm

Yes please - I'll even take one without LWBs, GTS may be the only option through...

[DrewM5]

Originally Posted by SteveC

Desire.

And yes, it is futile. I still can't quite swallow that with all the performance and everything the M5 has to offer, that in certain circumstances, the M135i was more fun to drive and felt the more capable car. Especially when the shortcoming is down to transmission programming and I need workarounds to make the M5 perform.....in certain circumstances.

There will always be cars that are more fun to drive in a particular set of circumstances. But you will never be able to get the "limo mode" ride out of that same M135. No one car is perfect in all scenarios.

You need to consider what the different settings do. Among other things, the different D settings will adjust the throttle sensitivity much the same way a SprintBooster will. A one inch depression of the go pedal will create more of a throttle reaction in D3 than D2 and more in D2 than D1.

In D1, you want the car to be smooth and power addition to be smooth without too easily downshifting. Take a scenario where you are cruising at 75 on the highway and come upon a car in the left lane doing 65. You slow to 65 and they move over. Now you want to gently roll back up to 75, so you depress the go pedal by about an inch and get exactly what you want.

Now, take that same scenario and the bozo in the left stays put, so you want to zip by him on the right in the middle lane. You seem to want to be able to press down the same inch and get a different response in that situation. How do you expect the car to know which situation it is facing? There is no electronic feature that currently can connect the transmission to your intention. And you wouldn't (or shouldn't) want one even if it existed. It certainly would add cost, weight and/or complexity to the car and you already have the perfect mechanism to connect your intentions with the transmission - your right foot!

Simply push an inch when you want a gentle roll on of speed, 2 inches when you want to speed up quickly and 3+ when you want to accelerate with max power.

[SteveC]

Originally Posted by DrewM5

There will always be cars that are more fun to drive in a particular set of circumstances. But you will never be able to get the "limo mode" ride out of that same M135. No one car is perfect in all scenarios.

You need to consider what the different settings do. Among other things, the different D settings will adjust the throttle sensitivity much the same way a SprintBooster will. A one inch depression of the go pedal will create more of a throttle reaction in D3 than D2 and more in D2 than D1.

In D1, you want the car to be smooth and power addition to be smooth without too easily downshifting. Take a scenario where you are cruising at 75 on the highway and come upon a car in the left lane doing 65. You slow to 65 and they move over. Now you want to gently roll back up to 75, so you depress the go pedal by about an inch and get exactly what you want.

Now, take that same scenario and the bozo in the left stays put, so you want to zip by him on the right in the middle lane. You seem to want to be able to press down the same inch and get a different response in that situation. How do you expect the car to know which situation it is facing? There is no electronic feature that currently can connect the transmission to your intention. And you wouldn't (or shouldn't) want one even if it existed. It certainly would add cost, weight and/or complexity to the car and you already have the perfect mechanism to connect your intentions with the transmission - your right foot!

Simply push an inch when you want a gentle roll on of speed, 2 inches when you want to speed up quickly and 3+ when you want to accelerate with max power.

You hit the crux of my problem but you've got it the wrong way around. When I'm moving through the gears and depress the gas pedal an inch I get perfectly adequate acceleration or a kick down, depending on the speed. But once the car has been cruising for a while and I move the gas pedal that same inch I get nothing....2 inches....nothing. I'm in D1, without changing anything and the throttle response changes according to whether the transmission is moving through the gears or has been sitting at the same speed for a while.
So you've exactly defined the problem, except its the car that changes its response....not me wanting it to. What I want is the same response it has when moving through the gears , not perfectly accelerative the one minute then practically brain dead and unresponsive the next.

Let me give you an example: Scenario1. I'm in D1 and gently pull away from a junction and at 30 mph in say 5th. I move the gas an inch and the transmission kicks down and we accelerate. I floor the gas and the transmission kicks down another 1 or 2 gears and we accelerate fiercely. Scenario 2. I'm driving along for 2 miles at 30 mph in say 5th. I move the gas pedal an inch and nothing happens, another inch...still nothing. I floor it and it kicks down a gear to 4th and accelerates moderately until it builds enough speed to accelerate harder. Same speed, same gear, same throttle response setting, utterly different response.

Let me replay your scenario with some minor mods. I pull onto a main road and accelerate and pretty soon I catch a car doing 50mph. He pulls over, I give an inch of throttle, accelerate efficiently to 60 and set cruise control. Perfect and as you'd expect in D1. Or....
I pull onto the main road and accelerate and pretty soon I catch a car doing 50mph and he doesn't pull over. Its illegal in England to pass on the inside so I follow him for 2 miles at which point he finally pulls over. I give the same inch of throttle....nothing happens...more, still nothing. WTF? Finally I give a lot of throttle and we finally get a kick down.

Call me picky, but I expect an M car in default mode to do better and the point is, it can. If it drove like it did in scenario 1, always providing the same level of throttle response and willingness to kick down I'd be perfectly happy.

[Bönz]

Originally Posted by DrewM5

Among other things, the different D settings will adjust the throttle sensitivity much the same way a SprintBooster will. A one inch depression of the go pedal will create more of a throttle reaction in D3 than D2 and more in D2 than D1

This is incorrect. The transmission settings in D or S do not affect the throttle map. There is a separate switch for this, much like the SprintBooster.

[P13tr0]

if the car didn't have adjustable settings, you would effectively be in sport plus for everything all the time. To me, this is the true default of the car. You have the option to use a tuned down mode, which actually makes a lot of sense while waiting for the car to warm up, stuck in traffic, cruising on the motorway or pootling around town.

If you don't like using grandad mode, then just use the car to its maximum potential. If you don't like using the car to its maximum potential, then why did you buy an M5?

I am not sure why I am bothering with this this reply, as you don't want to accept that you may be wrong, which brings me to my final point, either shut up and get on with it, or sell the car and get something else!

[Wills2]

Originally Posted by Bönz

This is incorrect. The transmission settings in D or S do not affect the throttle map. There is a separate switch for this, much like the SprintBooster.

Agreed the throttle settings also changes something to the wastegate control

Some one from BMW said:


By selecting the Sport or Sport plus accelerator mode, we can really feel the additional boost to the response. How does that work?

In Sport or Sport plus mode, a suitable VALVETRONIC controller and the waste gates keep the turbocharger in the higher speed range. Normally, the waste gate used to regulate the charging pressure opens so that the exhaust gas flows out with the minimum possible loss. Pressure is built up again only when I hit the accelerator. For an improved response, I leave the waste gate closed until I need it for regulating. The exhaust gas then always passes over the turbine, which then runs at a considerably higher speed. When even more power is demanded, it is immediately available. However, I have a gradually rising counterpressure that causes a slight rise in consumption.

[Bönz]

I have no idea who said this, where it comes from or what it means. It sounds like an ECU talking in first person. In any case, it is poor diction and hard to follow. The driver of the vehicle doesn't have direct control over the waste gates.

But I know this: The S63Tu will produce full boost (full power) on any throttle setting when your foot is to the floor. The accelerator mode control changes only the MAPPING. Sure you will get more boost SOONER in the pedal stroke in Sport and Sport+, but you will not get more peak boost. The accelerator setting only affects the ratio between pedal movement and the Valvetronic throttle system.

There isn't one single control that directly alters the engine's output. Indirectly, the stability and traction control systems (if on) will reduce engine torque (and selectively apply the brakes) to prevent spins and slides. But as we know the "nanny" intervention can be reduced by switching on MDM or switching them off altogether.

[Wills2]

Originally Posted by Bönz

I have no idea who said this, where it comes from or what it means. It sounds like an ECU talking in first person. In any case, it is poor diction and hard to follow. The driver of the vehicle doesn't have direct control over the waste gates.

But I know this: The S63Tu will produce full boost (full power) on any throttle setting when your foot is to the floor. The accelerator mode control changes only the MAPPING. Sure you will get more boost SOONER in the pedal stroke in Sport and Sport+, but you will not get more peak boost. The accelerator setting only affects the ratio between pedal movement and the Valvetronic throttle system.

There isn't one single control that directly alters the engine's output. Indirectly, the stability and traction control systems (if on) will reduce engine torque (and selectively apply the brakes) to prevent spins and slides. But as we know the "nanny" intervention can be reduced by switching on MDM or switching them off altogether.

The Head of BMW engine development in an interview with this website, I agree on the diction but perhaps it's just a translation issue?

http://f10.m5post.com/forums/showthread.php?t=588858

Scroll down, if you care to, it's half way down.