Clutch slur/slurry?

[Jaw_F430]

Can someone describe how this feels and when it happens.

I have had my car for a about 5 days now and just want to make sure everything is how if should be :-D

The only thing I have noticed with the upshifts is when I take it to the redline and change it seems to have a slight slip but I don't know if thats what all the SMGs are like.

When I drive it "normal" the gearchanges are smooth.

[Mark CSL]

Put it in s6 and drive it at 60mph in 4 gear then nail it and chang up to 5 gear it should chang up with a bang and not sound like it is hesatating

The gear change remembers how you drive there is a part in the manuel
how to reset it

If i rember right drive at 50mph then pull the 2 flappy paddles back for a couple of seconds and thats it done i think

But look at the books that came with the car :thumbs: that always helps :hahaha:

[Jaw_F430]

Cheers Mark


I will try point one and also have a quick flick through the manual lol. :beer:

[NZ_M3]

The slurr is basically a hesitation either on an upshift or downshift (usually downshift) ... where the rev stays up momentarily before dropping.
It can also happen when you first step on the accelerator from a stand still, and the clutch don't engage straight away (like mine was ... it'd hesitate, rev up .. then engage - basically not a smooth engagement)

As if one's held onto the clutch without releasing for a tad too long (or riding the clutch).

The reset Mark mentions works most of the time (provided that you give it some beans afterwards and don't settle back on lifting off the throttle on down or upshifts). The key is to keep your foot planted when you shift gears.

Occassionally the slurring can also be resolved by the dealership by reinitialising the clutch take up point in the SMG (which is usually the cause - due to the self adjusting pressure plate that these cars carry - they suck period).

Or if you are like me ... it could also be caused by a faulty release bearing - mine was and on occasions the release bearing would stick and cause the clutch to slurr - it is apparent when you drop the gearbox and look at the release bearing - it'll be unevenly worn causing it to stick on the shaft and release fork. Lucky for me I caught it early and had the dealer drop the box ... it cause zero wear to my clutch or pressure plate - but if you leave it long enough it'll chew up your clutch plate for sure.

[Mark CSL]

NZ_M3
I have never had it on the downshift .

I have had 3 clutches and flywheels 1 in each of my 3 CSLs, and never
have they been worn out, the CSL i have now had done 52000 miles when it got replaced and it was like new, but there was burn marks on the flywheel (never a good sign )
The slave cylnder does not take up the small amount off wear on the clutch .

[NZ_M3]

NZ_M3
I have never had it on the downshift .

I have had 3 clutches and flywheels 1 in each of my 3 CSLs, and never
have they been worn out, the CSL i have now had done 52000 miles when it got replaced and it was like new, but there was burn marks on the flywheel (never a good sign )
The slave cylnder does not take up the small amount off wear on the clutch .

Mark

when mine started doing it it was probably mostly due to the faulty release bearing (rather than a software issue) - hence the difference in when it did it (up or downshift, mostly downshifts, and on take off). When my clutch and pressure plate came out it was like new, zero wear (testiment to SMG I think) .. (car had 18,XXX km on the clock) ... no wear on the flywheel either (like new as well). Thank goodness for BMW warranty that covered the work (didn't look that hard to do though to be honest).

The clutch kit is made by LuK and features self adjusting pressure plate - i.e. it tries to keep a constant clutch travel (or in this case pressure plate take up point) as the clutch worn down. This combined with the dual mass flywheel means that there's a lot of interplay between the pressure plate adjusting, the flywheel adjusting the load ect ... causing the occasional sluring.

I do suspect that some of the slurring is caused by the release bearing issue though - when mine came out it was very inconsistently worn.

[cslbecks]

Ive had a fairly good look through all my manuals and i cant find how to "reset" the clutch anywhere??? I will try marks advice above today - but if that doesnt do it does anyone know exactly how to reset it yourself??

[RichW]

Its definitely in the manual - in the SMG section as i was looking how to use the launch control :whistle: when i found it.

From memory, as Mark says, its something pull back on both paddles for a couple of seconds :)

[XPorker]

During my marathon trip around France my car went through a phase of slurring on up changes. It got to a point where I thought the clutch would give up the ghost altogether. (It's under warranty so would have been an inconvenience but not a great expenditure !)
I had however been driving it VERY aggressively in S5 (up the very tight, but fast and winding road leading up to Mount Ventoux)

The following day the problem seemed to have eased and two days after everything was back to normal (and hasn't been an issue since)

I'm shocked at just how adaptive" the car is to driving technique as mentioned earlier in this thread.

In my experince if you drive the car in S5 for any length of time without driving it hard it really seems to "adapt" badly and leads to really poor gearshift quality ?
Anyone else found this to be the case ?

[englebert]

Mine can get worse over a period of time, as i never use full throttle upshifts on the road, as when pottering i don't want a jerky shift (i'm normally in S3 maximum...).

Every time i've taken it on track in S6 mode its felt better afterwards.

[cslbecks]

I "reset" mine today by doing 50mph and pulling in both paddles - after about 2 secs i felt the car slightly hesitate as if it had done something - so i assume this has reset things. I then tried to drive the rest of the way home at full tilt, traction off and S6, banged up and down the gears full throttle etc. That said though, if anything it felt more sluggish than before!!?? Maybe it needs a few more runs flat out?? Im at Brands on 25th so maybe that will sort it out??

[Jaw_F430]

The only thing I can see in the manual about resetting is when you have changed a tire or had snow chains on.

It says drive above 20mph, select N and then hold both paddles for approx 2 seconds.

Or do you do it when it is in drive, S6?

[XPorker]

I've spoken to a BMW teccy mate this afternoon (having looked in the SMG handbook for the information given earlier in this thread)

He's not aware of any such system adaptiom for the SMG box. I'm popping in to see him tomorrow to see if any such information exists.
I'll update you as and when.

He did say that when the system adaption is carried out in the workshop with the computer hooked up to the car that you hear all sorts of clunks and bangs as the system selects gears and measures the clutch take up point.

I'll withold judgement on the "two paddles held in at the same time adaption process" until I know otherwise categorically, but it doesn't sound encouraging . . . .

[SpineOnABap]

The only thing I can see in the manual about resetting is when you have changed a tire or had snow chains on.

That's right. You only only need* to do it when changing tyres because it resyncs with the rolling radius of the new tyres.

If you want to 'reset SMG' then a dealer can do it (SMG teach-in, which is what Xporker is talking about above). The paddle thing will do jack-shit for the old 'slur issue'.

* saying that I only experienced a problem once in over 6 years of SMGII use where the paddle thing resolved it -when I changed tyre rolling radius dramatically. Switching between similar/same sized tyres never bothered it in my experience.

Basically, like many other things I think - once upon a time someone on a forum mentioned that the paddle thing does some kind of super SMG reset / reinitialisation / whatever you want to call it - and it became 'fact' :-D

[XPorker]

The only thing I can see in the manual about resetting is when you have changed a tire or had snow chains on.

That's right. You only only need* to do it when changing tyres because it resyncs with the rolling radius of the new tyres.

If you want to 'reset SMG' then a dealer can do it (SMG teach-in, which is what Xporker is talking about above). The paddle thing will do jack-shit for the old 'slur issue'.

* saying that I only experienced a problem once in over 6 years of SMGII use where the paddle thing resolved it -when I changed tyre rolling radius dramatically. Switching between similar/same sized tyres never bothered it in my experience.

Basically, like many other things I think - once upon a time someone on a forum mentioned that the paddle thing does some kind of super SMG reset / reinitialisation / whatever you want to call it - and it became 'fact' :-D

That's what I was trying to say SOAB, but I was trying to be a bit more diplomatic about it ! Another internet forum myth methinks :thumbs:

[RichW]

To clear this up :

"After changing a tyre or wheel and after fitting or removing snow chains, the slip monitoring feature of the SMG Drivelogic must be allowed to to adjust to the modified status.

Initialise the system again:

1. On a straight road, driving at a speed of more than 30 km.h (20mph), move the selector lever tot the neutral position N
2. Pull both shift paddles for approx. 2 seconds.

If you do not perform the initialising routine, the system will graduallly learn the modified status automatically, as you drive. You will notice this by the clutch being breifly disengaged and engaged"


So it is a reset, although not as we know it :-D

[cslbecks]

Is there any benefit whatsoever in doing this IF you have NOT fitted snowchains or changed a wheel???

[SpineOnABap]

Is there any benefit whatsoever in doing this IF you have NOT fitted snowchains or changed a wheel???

Nope

Although there's plenty who've claimed they can detect a huge improvement, but that's just Jedi mind tricks :bigcry:

[cslbecks]

When i did this i didnt put the car in neutral - it was in S5 and i was doing a steady 50mph, pulled both paddles in for about 5 secs and the car sort of hesitated very slightly. To be honest car felt a little more sluggish on the changes - but im hoping that was my imagination!!

[SpineOnABap]

When i did this i didnt put the car in neutral - it was in S5 and i was doing a steady 50mph, pulled both paddles in for about 5 secs and the car sort of hesitated very slightly. To be honest car felt a little more sluggish on the changes - but im hoping that was my imagination!!

You do have to be in neutral so you won't have done anything .. other than change gear up or down or not at all depending on your timing when pulling both paddles :-D

If you're unsure the procedure is in the M3 handbook in the 'changing tyres' section :thumbs:

[cslbecks]

Well if this doesnt have any benefit other than when changing tyres or chains then dont think i will bother!!!