Clutch / Gearbox

[The Gorilla]

Hi,

I can not help but notice that over the last
few months as many of the CSL's start
to put on the miles, and there appears
quite a few using them repeatedly on the Track as well,
that Clutch and gearbox issues are starting
to become more or less the norm.

Many good points and useful observations
have been made, but it all feels a bit like
putting a 'plaster' over the wider issues and
hoping it will either go away or just sort
of fix itself.

The element of wear on the many components
involved in the SMG 11 process is unhelpful
as the mileage starts to increase, as with all
things of this design.

But the word 'Slur' really meaning slip is now
a common issue with many owners and drivers.

Just wondering if with the information, resources,
and the Technical data available, via this Forum,
that some sort of 'remeadial' or 'to do' type
info sheet could be prepared, or anything else
that that others feel may assist.

Just wondering how others viewed this.

I suppose if I see about 20 CSL cars for sale
shortly then I know what the common consenses
is !!

Regards,

The Gorilla.

[Dan]

I would be a good idea I think, I for one am someone who is suffering from this supposed 'slur' or as you say clutch slip, I tried the car in S6 with the DSC off this morning and it made no difference to how the car changed gear, there is constantly a slip and it's always there now, the only thing that makes it better is me lifting off on upshifts which tends I feel to put less strain on the car in general.

I'm not particularly impressed with this, a 60k car and huge manufacturer it should be spot on IMO, for BMW to have no real solution to this problem is very bad! :banghead:

I'm a fickle (sp) fucker as it is so it wouldn't take a lot for me to sell the CSL on and try something else, seeing as it's not an everyday car for me anymore I hope BMW/Murkett's can cure it when it's in for it's inspection or I'll be CSL'less very soon... I have a very big itch for a Porka or a Ferrari again at the moment! :whistle: :banghead:

[grumps]

Yep with you on that idea! I love my csl but its been nothing but trouble in 6 months of ownership (alternator,rear springs,viscous fan radio,oil leak,battery, v belt tensioner and pulleys and now the clutch) and am also thinking of moving it on! should have got a gt3.
p.S and thats at 48k:bigcry:

[mickaldo]

Yep with you on that idea! I love my csl but its been nothing but trouble in 6 months of ownership (alternator,rear springs,viscous fan radio,oil leak,battery, v belt tensioner and pulleys and now the clutch) and am also thinking of moving it on! should have got a gt3.
p.S and thats at 48k:bigcry:
wish id kept my gt3!

[glendog74]

I feel quite lucky in my 2 years ownership to have just had an alternator & throttle potentiometer go tits up! Owning a CSL has been a very positive experience for me :thumbs:

[shane@mbtech]

Mine has been great for the year I have owned it.

Its like any car, just the luck of the drawer.

Some may have a friday car:whistle:

[Kev.H]

if you dont short shift it doesnt slur thus redline and its fine :bigcry:

[NZ_M3]

Aren't you running a full drenth sequential box on your car Gorilla?? This issue shouldn't trouble you at all :hahaha:


Anyway ... back on topic

My take on this is three fold.

Yes there's a genuine software issue with the system that will clear if you catch it early - but it will eventually come back depending on the type of driving and driving style used.

Secondly, the mechanical side and this relates to the SAC clutch pack. The interface between this and the software isn't that great and over time the system either over or under-compensates for wear thus the experienced slip or slur.

Thirdly and this is when the software isn't updated consistently or reset periodically and the eventual clutch plate wears out or the flywheel becomes worn, or another part of the system (such as the release fork, release bearing, plastic sleeve guide) eventually wear out causing the system to 'catch'.


I have personally NEVER experienced the so called 3rd to 4th gear slur.

I have however experienced the take off slur and this was quickly corrected with a reset.

Now to the reset part: I have a suspicion that the dealerships may sometimes not be doing the correct reset on the software. After doing a bit more reading and playing with my Autoenginuity tool, it turns out there's actually 5 different commands that is involved with the SMG clutch.

First is a soft clutch reset (I suspect this is the same as the drive above 30mile/h, in neutral and pull both paddle back reset) - it reinitialises the system vis-a-vis the wheel speed rotation sensors.

Second is a Clutch Slip reset (this is by far the most noticeable and effective reset when you are experiencing s slight slur when taking off) - I do this reset on my car regularly and have not experienced another take off slur ever since.

Third is a clutch curve re-adaptation - this is an interesting one - I tried this on my car the other day and to my surprised it changed the whole dynamic of the way the car shifted and released the clutch. I have to honestly say that this is the MOST NOTICEABLE Reset of them all - whiplash is an understatement with this reset. I was almost a bit concerened that I'd broken my car. But after taking the car for a good moderate drive in different shift speed settings with part and full open throttle shifts I could immediately feel the system "adapting" to the driving style, eventually it became crisp and sharp with no hint of hesitation or clutch slur. I believe this is the full initialisation that the dealership uses when a new clutch pack is installed or a SMG pump is changed.

The fourth is called the clutch take up point reset - I usually do this in conjunction with the clutch slip reset and it works well and take all of 2 seconds to do. With this reset the clutch pack is simply opened and closed once.

The fifth and is one that I have not tried is the longitudinal acceleration sensor reset. This is part of the SMG system and on the system it is a Mandatory Reset whenever the SMG pump has been replaced. I have not tried this, so am not sure what it does exactly yet.


My take on this whole saga.

Yes there's an issue, but being a widely reported item I do think that owners actively 'look' for it, and we hear it on the net as a result.

I do believe that the only way around this is:

1. Buy a tool or buddy up with your indy shop with one and reset your system on a regular basis before anything mechanical is worn;

2. (and somebody really needs to try this out) - use a Non SAC clutch kit with the exact same clamping pressure as the OEM system and if possible run a single mass flywheel rather than a dual mass one (but not a solid centre clutch, a sprung one if you like your drivetrain components).



I thought it might be helpful also if we all record our driving styles and see if there's a common denominator, I've deviced the following template:

When Engine Cold (shift speed): s3
When Engine at operating temp (shift speed): s4
Shift speed used at track : s5 or sometimes s4
Lift on upshift: No
Lift on downshift: sometimes
Full throttle redline upshifts periodically: yes
Part throttle redline upshifts : never
Launch Control use: never
Software reset period: usually every two to three weeks

[Kev.H]

how do you do this one out of interest please ?

Second is a Clutch Slip reset (this is by far the most noticeable and effective reset when you are experiencing s slight slur when taking off) - I do this reset on my car regularly and have not experienced another take off slur ever since.

[outnumbered]

Yes there's an issue, but being a widely reported item I do think that owners actively 'look' for it, and we hear it on the net as a result.


That's a good point. There was a lot of discussion about this 2-3 years ago over on mtorque/bm3w and I think it resulted in pretty much every CSL in the country spending a day at Murketts !

[shimmy]

That's a good point. There was a lot of discussion about this 2-3 years ago over on mtorque/bm3w and I think it resulted in pretty much every CSL in the country spending a day at Murketts !

very true of must internet issues but clutch slur is not one of them..........its real:thumbs:

[weedavey]

Heres me in mine.


When Engine Cold (shift speed): s3
When Engine at operating temp (shift speed): s6
Shift speed used at track : NOT YET
Lift on upshift: No
Lift on downshift: sometimes
Full throttle redline upshifts periodically: yes
Part throttle redline upshifts : never
Launch Control use: never
Software reset period: Not yet.

[Dan]

I have personally NEVER experienced the so called 3rd to 4th gear slur.

First is a soft clutch reset (I suspect this is the same as the drive above 30mile/h, in neutral and pull both paddle back reset) - it reinitialises the system vis-a-vis the wheel speed rotation sensors.

When Engine Cold (shift speed): s3
When Engine at operating temp (shift speed): s4
Shift speed used at track : s5 or sometimes s4
Lift on upshift: No
Lift on downshift: sometimes
Full throttle redline upshifts periodically: yes
Part throttle redline upshifts : never
Launch Control use: never
Software reset period: usually every two to three weeks

Some great info as usual there mate :smokin::thumbs:

Mine seems to 'slip' into 5th & 6th gear, rather than 3rd to 4th Gear, it usually happens at full throttle, I can make it better by slightly lifting when upshifting but seeing as that car should already be doing this for me I would like to keep the throttle nailed!

Can you give any more details on the 'Soft Clutch Rest', is it simple as it sounds, go above 30mph, knock the car into neutral and pull both paddles back?

Finally to give some further info this is my take on use:

When Engine Cold (shift speed): S5
When Engine at operating temp (shift speed): S5
Shift speed used at track : Not been on track yet
Lift on upshift: Sometimes
Lift on downshift: Yes, usually
Full throttle redline upshifts periodically: No
Part throttle redline upshifts : No
Launch Control use: Never
Software reset period: None whilst in my ownership (3-4 months now)

[thegingerninja]

Mine has never had any issues, just follow these steps:

always change gear with your foot to the floor - this may sound nuts, but it is very easy. If I want a nice steady drive, I change gear at 1500prm with the throttle at 100%. This makes the computer software register a 100% open throttle gear change and thus the clutch release duration is kept to a minimum (i.e. no slurring) You have to imagine what the computer "thinks" as you ask it to change gear. Just go through your mind how you would drive a manual car. If you want a nice smooth gear change, you release the clutch pedal gently. The CSL software will self learn the way you drive the car - so lifting between gear changes will cause slurring.

This is the reason why most people find their cars are brilliant after a thrashing on a trackday, but it tails off in coming months after that.

If you only allow the computer software to register 100% open throttle gear changes, it will release the clutch quicker all the time.

I have doing this now for nearly 4 years - gear changes are so good I only ever use S4. S6 almost snaps my head off! Most other people who have tried this also report that after a short period the clutch slur goes, provided it wasn't completely buggered before.

In most cases of slurring - clutches have been found be well within tollerances. It's the transfer onto the flywheel that does it.

[wazadaza]

Great advice as ever! Does anyone know how much BMW charge for these resets and software upgrades on the box?

[weedavey]

Mine has never had any issues, just follow these steps:

always change gear with your foot to the floor - this may sound nuts, but it is very easy. If I want a nice steady drive, I change gear at 1500prm with the throttle at 100%. This makes the computer software register a 100% open throttle gear change and thus the clutch release duration is kept to a minimum (i.e. no slurring) You have to imagine what the computer "thinks" as you ask it to change gear. Just go through your mind how you would drive a manual car. If you want a nice smooth gear change, you release the clutch pedal gently. The CSL software will self learn the way you drive the car - so lifting between gear changes will cause slurring.

This is the reason why most people find their cars are brilliant after a thrashing on a trackday, but it tails off in coming months after that.

If you only allow the computer software to register 100% open throttle gear changes, it will release the clutch quicker all the time.

I have doing this now for nearly 4 years - gear changes are so good I only ever use S4. S6 almost snaps my head off! Most other people who have tried this also report that after a short period the clutch slur goes, provided it wasn't completely buggered before.

In most cases of slurring - clutches have been found be well within tollerances. It's the transfer onto the flywheel that does it.

Another method for me to try, thanks.

[Dan]

Mine has never had any issues, just follow these steps:

always change gear with your foot to the floor - this may sound nuts, but it is very easy. If I want a nice steady drive, I change gear at 1500prm with the throttle at 100%. This makes the computer software register a 100% open throttle gear change and thus the clutch release duration is kept to a minimum (i.e. no slurring) You have to imagine what the computer "thinks" as you ask it to change gear. Just go through your mind how you would drive a manual car. If you want a nice smooth gear change, you release the clutch pedal gently. The CSL software will self learn the way you drive the car - so lifting between gear changes will cause slurring.

This is the reason why most people find their cars are brilliant after a thrashing on a trackday, but it tails off in coming months after that.

If you only allow the computer software to register 100% open throttle gear changes, it will release the clutch quicker all the time.

I have doing this now for nearly 4 years - gear changes are so good I only ever use S4. S6 almost snaps my head off! Most other people who have tried this also report that after a short period the clutch slur goes, provided it wasn't completely buggered before.

In most cases of slurring - clutches have been found be well within tollerances. It's the transfer onto the flywheel that does it.

That must be hard to comprehend, so accelerator FLAT to the floor regardless of whether or not your changing gear at 1500rpm or 8000rpm!? :bigcry:

I've just been out in mine and given it a pasting for around 35 miles, basically changed quick as I could in all gears, varied throttle positions and not a bloody thing, no slur at all and even on occasions flooring it in second to the redline through the gears it really went well, banging into gear and got my pulse racing! :smokin: :supz:

Great advice as ever! Does anyone know how much BMW charge for these resets and software upgrades on the box?

I spoke to Andy at Murkett's yesterday and he advised it was £45 for a software update :thumbs:

[weedavey]

Mine has never had any issues, just follow these steps:

always change gear with your foot to the floor - this may sound nuts, but it is very easy. If I want a nice steady drive, I change gear at 1500prm with the throttle at 100%. This makes the computer software register a 100% open throttle gear change and thus the clutch release duration is kept to a minimum (i.e. no slurring) You have to imagine what the computer "thinks" as you ask it to change gear. Just go through your mind how you would drive a manual car. If you want a nice smooth gear change, you release the clutch pedal gently. The CSL software will self learn the way you drive the car - so lifting between gear changes will cause slurring.

This is the reason why most people find their cars are brilliant after a thrashing on a trackday, but it tails off in coming months after that.

If you only allow the computer software to register 100% open throttle gear changes, it will release the clutch quicker all the time.

I have doing this now for nearly 4 years - gear changes are so good I only ever use S4. S6 almost snaps my head off! Most other people who have tried this also report that after a short period the clutch slur goes, provided it wasn't completely buggered before.

In most cases of slurring - clutches have been found be well within tollerances. It's the transfer onto the flywheel that does it.

I have just tried this. This morning i went out and from the get go was using 100% foot to the floor shifting on upshifts (bit harsh in the lower gears) . Regardless of revs foot was to the floor.
Problem solved............................................ ...................................
for the majority of my outing.

After the car had warmed up i selected S6 and remained changing at foot to floor. after a while i noticed a slight hesitation at around 5500rpm this was followed by more and more sluggish changes so eased back and changed to i think it was s4, Problem gone again!?!?

My question is does the software learn different driving styles in different modes?

I didn't select th s6 mode again as i was nearing home and steadily cooloing calming down for parking up and switching off. Will be experimenting again next time i'm out but for the first part of this drive the car felt sharp, crisp and precise.

TRY IT.

[SpineOnABap]

Not sure about only changing with 100% throttle openage, even if it is low RPM you've still gotta mash it :hahaha: - would get interesting in the village particularly in traffic in 1st or 2nd :hahaha:

Someone posted that they drive like that AGES ago on Mtorque/BM3W - Ninja it's not you is it? (Simon?)

[Dan]

Not sure about only changing with 100% throttle openage, even if it is low RPM you've still gotta mash it :hahaha: - would get interesting in the village particularly in traffic in 1st or 2nd :hahaha:


That's what I can't seem to get a grasp off, don't think I'll try it tbh :hahaha:

[thegingerninja]

Not sure about only changing with 100% throttle openage, even if it is low RPM you've still gotta mash it :hahaha: - would get interesting in the village particularly in traffic in 1st or 2nd :hahaha:

Someone posted that they drive like that AGES ago on Mtorque/BM3W - Ninja it's not you is it? (Simon?)

Yep - it's me, Elliot.

I've only ever driven my car this way ever since I owned it. I probably gave a fairly short description of how to drive it like this.

Obviously you can't change gear at 100% open throttle from 1st to 2nd in traffic. I drive mine in S2 or S3 until it has warmed up. I only use my CSL as a toy now, so I rarely drive in any traffic to be honest.

I tend to change gear very early in the rev range (1500 rpm) or very late (above 6000 rpm) to stay out of the maximum torque band, as it appears to be the torque that causes the slurring.

I have said before that it sounds like complete madness to drive like this, but it is surprisingly easy ( not in traffic). Even if I'm just gently cruising down the road at 50 mph following a line of traffic and I want to change from 5th to 6th, I floor the throttle flick the paddle for 6th, as soon as the gear is fully engaged, lift off back to a balanced throttle - you only gain a couple of mph, give it a go. It just sounds odd when you read it here on a forum, but if you get in your car and try it, it's not a problem. You just have to programme yourself to get through the gears quickly - 40 mph in 6th gear isn't a problem. If anyone has really bad slurring, drop into S2 or S3, and perform 100% throttle changes at 1500 rpm, or even 1200 rpm if you can. The lower the revs, the better. Then build it back up to S4, and S5.

The whole issue of the clutch slur is not a mechanical one in my opinion, the actual cause is down to the software releasing the clutch too slowly. The computer only has 3 variables to take into account when orchestrating a gear change, road speed, throttle position (engine load), and revs. If you only have 10% throttle loading, then the clutch operation is going to be fairly gentle to give a smooth drive - I think this becomes absorbed into the self learning part of the software and manifests into slurring at full throttle, either as slow clutch release or re-loading the engine too soon. My car certainly feels as if there is a definate gap between engaging the gear and reinstating full load. Either way, my car has been mint ever since I drove it like this. If I had any computer skills I would video the way I drive and load it onto youtube....but I haven't the faintest idea - any takers?

[TANKSLAPPER]

Yep - it's me, Elliot.

I've only ever driven my car this way ever since I owned it. I probably gave a fairly short description of how to drive it like this.

Obviously you can't change gear at 100% open throttle from 1st to 2nd in traffic. I drive mine in S2 or S3 until it has warmed up. I only use my CSL as a toy now, so I rarely drive in any traffic to be honest.

I tend to change gear very early in the rev range (1500 rpm) or very late (above 6000 rpm) to stay out of the maximum torque band, as it appears to be the torque that causes the slurring.

I have said before that it sounds like complete madness to drive like this, but it is surprisingly easy ( not in traffic). Even if I'm just gently cruising down the road at 50 mph following a line of traffic and I want to change from 5th to 6th, I floor the throttle flick the paddle for 6th, as soon as the gear is fully engaged, lift off back to a balanced throttle - you only gain a couple of mph, give it a go. It just sounds odd when you read it here on a forum, but if you get in your car and try it, it's not a problem. You just have to programme yourself to get through the gears quickly - 40 mph in 6th gear isn't a problem. If anyone has really bad slurring, drop into S2 or S3, and perform 100% throttle changes at 1500 rpm, or even 1200 rpm if you can. The lower the revs, the better. Then build it back up to S4, and S5.

The whole issue of the clutch slur is not a mechanical one in my opinion, the actual cause is down to the software releasing the clutch too slowly. The computer only has 3 variables to take into account when orchestrating a gear change, road speed, throttle position (engine load), and revs. If you only have 10% throttle loading, then the clutch operation is going to be fairly gentle to give a smooth drive - I think this becomes absorbed into the self learning part of the software and manifests into slurring at full throttle, either as slow clutch release or re-loading the engine too soon. My car certainly feels as if there is a definate gap between engaging the gear and reinstating full load. Either way, my car has been mint ever since I drove it like this. If I had any computer skills I would video the way I drive and load it onto youtube....but I haven't the faintest idea - any takers?



Love you Ginger

Normally, you just talk Bollocks :thumbs:

lol

[Bounce]

Love you Ginger

Normally, you just talk Bollocks :thumbs:

lol:hahaha::hahaha::hahaha:

[The Gorilla]

Hi,

Not wanting to shoot off on another tangent,
but while researching the 'SAC' Clutch I came
across this article.

Given the design of the DCT clutch system,
odds on one clutch, evens on the other, then
as explained in the article, there is a downside
to it in a performance car.

http://www.autoevolution.com/news/how-dual-clutch-transmissions-work-5458.html

Anyway back on topic, its interesting that companys like
Valeo offer 'SAC' replacement clutches which drops
the Dual Mass Flywheel for a single mass and then
drops the 'SAC' pressure plate for a more normal
sprung type finger one.

Many 328/528 owners report much better gear changes
and clutch feel once the original SAC is replaced with
these type conversion kits.

I am starting to think along the lines of a Steel
single mass flywheel, but not to light so that stall
and inertia become issues,retain the E36 M3 Evo pressure
plate and the E46 M3 standard disc or maybe a cerametallic
one.

There is cleary a design flaw to the SAC pressure plate,
so although I am reading posts where owners are undertaking
different proceedures or driving sequences to make the
issues better, I do not believe you can over come flawed
component design, longterm, with these type solutions.

Still its certainly stoking the debate, as Clutch Slip is an
issue on the SMG 11.

Regards,

The Gorilla.

[NZ_M3]

how do you do this one out of interest please ?

Second is a Clutch Slip reset (this is by far the most noticeable and effective reset when you are experiencing s slight slur when taking off) - I do this reset on my car regularly and have not experienced another take off slur ever since.

This is done via a third party tool - mine's made by Autoenginuity from the States. In terms of the SMG component sensors and resets it is dealership level (if not slightly better as it monitors and allows reset of individual components and sensors rather than a generic command that might include a whole host of things).


Can you give any more details on the 'Soft Clutch Rest', is it simple as it sounds, go above 30mph, knock the car into neutral and pull both paddles back?

Okay, after reading the SMG training manual 3times I've come to the conclusion that the soft reset really has more to do with the DSC system than the SMG to be honest - basically it resets the volatile memory part of the DSC system in correlation to the wheel speed sensors (i.e. if you change wheels sizes ect). This reset is described in the owner's manual - but I can see it as a separate function on the Autoenginuity tool.


My question is does the software learn different driving styles in different modes?

To an extent yes - Although within the non Volatile memory part of the SMG control unit and the MSS54 DME are pre-determined codes and change patterns that never change - these outline the parameters so whatever changes within the volatile memory will still be within these parameters.


The whole issue of the clutch slur is not a mechanical one in my opinion, the actual cause is down to the software releasing the clutch too slowly. The computer only has 3 variables to take into account when orchestrating a gear change, road speed, throttle position (engine load), and revs.

That's incorrect I am afraid - it's way more complicated than that (I wish it was that simple, although I imagine if it was it'd drive like complete bonkers). The SMG Control Unit is basically a signal receiver and hydraulic operator - it's the MSS54 DME and the DSC Control unit all together that determines how the gear change is executed via the SMG CAN bus.

If you like the MSS54 DME is the brain and the SMG control unit the hands and feet of the system - the CAN bus is the spinal cord.


SMG II Control Unit
......
Communication with the DME is via a dedicated CAN bus (SMG II CAN Bus). Based on
instructions received from the DME the SMG II control unit manages the clutch solenoid
valve, the selector shaft up and down solenoids, and the selection angle solenoid.
*****
While the SMG II control unit receives many of the inputs and manages the control of the
hydraulic system, the DME is responsible for and controls all gearshifts. Sensor inputs
received by the SMG II control unit are relayed to the DME for processing and monitoring.

And these are the signals monitored via the CAN Bus:

Engine Speed
Engine Coolant Temp
Engine Oil Temp
Intake Air Temp
PWG EDR Feedback Pots
Wheel Speed
Transverse Acceleration
Steering Angle
Cruise Status
Parking Brake
Door Contacts
Brake Light Switch
Key Memory

And I've not even gone into what the input signals are monitored by the SMG control unit and what is communicated with the MSS54 DME ...

So way more than just the road speed, throttle position and revs that you speak of.



I will come back to this a bit later. Having read the actual SMG training manual 3 times, I actually now have a much better understanding of how the system works.

[shimmy]

i dont understand any of this but i love reading it :thumbs:

[Bounce]

i dont understand any of this but i love reading it :thumbs:+1;)

[glendog74]

i dont understand any of this but i love reading it :thumbs:

+2 ;)









Just happy that mine doesn't slur :thumbs:

[TheBigDog]

[quote=glendog74;47303]+2 ;)

lol!! :hahaha:

[TheBigDog]

+2 ;)









Just happy that mine doesn't slur :thumbs:

Yep - the red wheels DO make you gay - you homo..!!! :gayfight:

[thegingerninja]

Love you Ginger

Normally, you just talk Bollocks :thumbs:

lol


Damn you! I thought I was sounding dead clever too.

To put it simply - my car is the best, all the others are fooked, end of.