clutch slurrrr

[Thorney]

Shimmy is in part right, there is certainly an issue in the interface between the clutch and the software, the problem is that the software is unable to adjust fast enough to allow for mechanical wear that the clutch naturally suffers, this wear also manifests itself in dirt build up etc, basically anything that causes the mechanical interface to differ (wear or lots of time in traffic - essentially the same thing to some extent).

The solution is regular re-calibration, think of it like rebooting your PC, every now and then you do that to clear out memory, IE cache etc etc, the PC doesn't 'need' it per se but it works better after its done. Sadly this re-calibration can only be done with a handful of diagnostic tools, we sue the Autologic (which is by far the most expensive but also the most sophisticated, with upgrades its nearly £15k) or even an older GT1 but these are rapidly getting out of date. BMW continually update the software (I'm not sure if they're trying to fix it or whatever) so you do need things updating.

Only advice I can give is do as we do and make sure every time your CSL goes into a dealer or indy for service is to ensure that the SMG calibration (full not just the bight points) is re-done each time, we include as part of any CSL we see even those in for a quick look over etc, it only takes 20 mins or so, less than that really. The alternative is to rag the crap out of the car regularly, this has the effect of keeping the clutch/flyhweel clean but it wont re-calibrate the software, theres no alternative really.

[Kev.H]

i had mine adjusted made a difference for a while.. seems the harder you drive the better the change i do find if i do a journey switch the car off then back on whilst its still warmed up I get a crisper change ?

[Bounce]

Im off to Murketts next week to get mine sorted,and a couple of other things under warranty.Must be the longest distance for warranty work anybody has travelled.St.ives to St.ives[well huntington] 366 miles.

[s.mac]

I'll be phoning Andy tomorrow, the software updates have really upset the car put your foot down and the dsc kicks in big time ! just no pull and feels like you've knocked the gear stick into neutral

[shane@mbtech]

Originally Posted by shimmy

well you asked for it so here is my view

ive read it before but i believe there is a problem with the SMG clutches with adjusting the bite points whilst it wears and is being used and abused, probably made worse when it is used hard over time

my first clutch lasted 42k miles but was slipping on and off for the last 10k miles. had a few teach sessions on it and went and away and came back still the same after a while

second clutch had hard use mostly on track but not only and has started to slip now in less than 2 years with 25k miles. I think if it would have been not under warranty i would have put up with it, played with it, made it better but eventually it would have needed changing

Somewhere the mechanics or the software on worn clutches deosnt work properly and it will be a big cost item in these cars if they need changing every 25-40k miles

Just have to keep mine slipping under 2 years!

Unless you pay a contribution, which I doubt they will let you, your new clutch will only have warranty until your warranty expires on the clutch they are replacing now. So you wont get 2 years on it I'm afraid shimmy.

[shane@mbtech]

Originally Posted by s.mac

I'll be phoning Andy tomorrow, the software updates have really upset the car put your foot down and the dsc kicks in big time ! just no pull and feels like you've knocked the gear stick into neutral

try turning traction off

[glendog74]

Originally Posted by lawsy

try turning traction off

[shimmy]

Originally Posted by lawsy

Unless you pay a contribution, which I doubt they will let you, your new clutch will only have warranty until your warranty expires on the clutch they are replacing now. So you wont get 2 years on it I'm afraid shimmy.

i can see ill have to try something crafty

[Mark CSL]

Originally Posted by shimmy

i can see ill have to try something crafty

There is the cheeze thing again dont get Daz and Alex started Shimmy

[NZ_M3]

Originally Posted by Thorney

Shimmy is in part right, there is certainly an issue in the interface between the clutch and the software, the problem is that the software is unable to adjust fast enough to allow for mechanical wear that the clutch naturally suffers, this wear also manifests itself in dirt build up etc, basically anything that causes the mechanical interface to differ (wear or lots of time in traffic - essentially the same thing to some extent).

I am more on the camp that it has more to do with the SAC (self adjusting clutch pressure plate) rather than the software not accounting for wear to be honest. The normal 6 speed get this on some occassions also - I certainly had it in my 3 pedal 6 speed M3 that was bad enough to warrant the dealer to swap out the clutch - when it came out, it was like new, but the self adjusting clutch mechanism had somehow locked itself and stopped moving.

Here's a possible experiment for somebody - get a pressure plate the same clamping rate as the OEM LuK unit but without the self adjusting mechanism - I wonder if it'll stop all that slurring that's going on!!.

To be honest though, I've only ever experienced the slurring on take off and never on shifting up or down - but then again I never use my car in traffic

Originally Posted by Thorney

The solution is regular re-calibration, think of it like rebooting your PC, every now and then you do that to clear out memory, IE cache etc etc, the PC doesn't 'need' it per se but it works better after its done. Sadly this re-calibration can only be done with a handful of diagnostic tools, we sue the Autologic (which is by far the most expensive but also the most sophisticated, with upgrades its nearly £15k) or even an older GT1 but these are rapidly getting out of date. BMW continually update the software (I'm not sure if they're trying to fix it or whatever) so you do need things updating.

Couldn't agree more. I am making it a habit of this now with my Autoenginuity tool. It takes no more than 10 minutes or so to reset everything and once it's done, it feels great!!