SMG 'clunk'

[sjb]

Hi. I forgot to add to my other post that when I test drove the CSL there was a slight clunk from the diff(?) on the upshift. Now I have a manual M3 so don't know the in's and out's of the smg. Silly question coming..... Do you have to lift off when shifting up or keep it planted? The seller said to lift a little for a sit second and this made it smooth. The shift was set to half way between soft and ferocious! Just checking there's not an issue with the diff....
Cheers.

[Bounce]

Hi. I forgot to add to my other post that when I test drove the CSL there was a slight clunk from the diff(?) on the upshift. Now I have a manual M3 so don't know the in's and out's of the smg. Silly question coming..... Do you have to lift off when shifting up or keep it planted? The seller said to lift a little for a sit second and this made it smooth. The shift was set to half way between soft and ferocious! Just checking there's not an issue with the diff....
Cheers.Bit of a clunk is fine,don't start lifting,it as it can cause the clutch to start slurring.

[0836whimper]

Basically when driven hard with no lift off, it feels like the diff is going to wrench itself out if the car. So sounds normal.

It's not smooth, but it's all part of the drama

[sjb]

Thanks for the replies :thumbs:

[Jon8710]

dont lift my friend or the clutch will slur and the gear change will stink,

keep your foot in it and allways drive it in manual with the gear change in one of the top 2 setting. :)

[martin770]

Drive it like ya stole it !!

[sjb]

Will take note of the replies when I have a second viewing in the next few days :thumbs:

[digi]

you may even get some hunting. That is normal too.

Also, it can buck around cold if you pussy foot it. My mrs always complains when she cold starts it.

As mentioned, drive it with vigor and it will reward. Another thing I noticed is that if you change the exhaust (gruppe m or something more free flowing), car is smoother. Maybe becoz during low revs I give it more beans becoz it sounds so much more wicked. :smokin:

[ZKMI]

Sorry to bring up an old thread guys.

I know some lift of the throttle when changing gears but the bmw manual says that you dont need to.

Just was wondering what your thoughts are on this and problems that are caused with the clutch when you do lift of the throttle..

Thank you.

[glendog74]

Sorry to bring up an old thread guys.

I know some lift of the throttle when changing gears but the bmw manual says that you dont need to.

Just was wondering what your thoughts are on this and problems that are caused with the clutch when you do lift of the throttle..

Thank you.

Never lift.

I've not had any issues with mine in 50k miles and lots of track days :whistle:

[petery]

I never lift and my clutch is on 76k miles and still working fine

[ZKMI]

Thats good news.

Thanks again.

[shane@mbtech]

Jim lifts all the time, mostly shirts though :gayfight::gayfight:

[ZKMI]

Lol.

Can someone explain in an easy way what the noise is if you dont lift and what is actually happening back there?

[adem.csl]

Simple.the gear change is soo instant that the diff knocks a bit the same as if you go from 2nd to 3rd and just throw ya foot off the clutch!its normal for a bit of knock under hard acceleration
You only need to worry if you got the box on its top setting and you go from 3 to 4 and get a screach this is because the box cant engage the syncromesh as quick as the electronic parts want too!!
Don't lift the smg is designed to change gear with the throttle fully depressed it can shut the throttle soo quick while changing gear you won't notice it
You won't have a problem with the clutch if you lift while changing it don't bother the engine cos it changes at its own rate anyway

[ZKMI]

Superb.

So either way is fine.. but its best to NOT lift.

Thanks again.

[adem.csl]

I don't
But my gearbox has a problem with 4th along with a couple other members!!!
Only when its proper hot and your really using it!!normal conditions its ok

[73CSL]

if you lift, I gather you can get clutch slur

I drive mine with full throttle changes & box in S5 , pretty much all the time

When I have the wife in the car , or the roads are wet & slippy I drive the car a lot more relaxed but still change gear without lifting , but the throttle might be at anything between 10% - 100% pressed ... I have found after a while , when I next go for a full throttle redline change in say 3rd, it picks up a slight amount of slur ....... 10 minutes of thrashing & it reverts back to 'normal'


Assume this is the software 'learning' & adapting for driving style ? If it is, would love a method of overriding

[glendog74]

Jim lifts all the time, mostly shirts though :gayfight::gayfight:

:hahaha: :hahaha: :hahaha:

[CraigMillwardCroft]

Jim lifts all the time, mostly shirts though :gayfight::gayfight:

:hahaha::hahaha::hahaha:

[digi]

if you lift, I gather you can get clutch slur

I drive mine with full throttle changes & box in S5 , pretty much all the time

When I have the wife in the car , or the roads are wet & slippy I drive the car a lot more relaxed but still change gear without lifting , but the throttle might be at anything between 10% - 100% pressed ... I have found after a while , when I next go for a full throttle redline change in say 3rd, it picks up a slight amount of slur ....... 10 minutes of thrashing & it reverts back to 'normal'


Assume this is the software 'learning' & adapting for driving style ? If it is, would love a method of overriding

sounds about right. I seldom drive my CSL nowadays and I generally have the battery disconnected. I found that I get ZERO slur from this. But if I keep the battery connected and was driving around town pussy footing, I do get a little slur due to I guess the gearbox learning.

I've recently not disconnected the battery as I find connect/reconnect when the weather is very dry, can cause some electrical spike, so its always connected nowadays. I just have to take her for a long cruise every other day. :finga:

[adem.csl]

if you lift, I gather you can get clutch slur

I drive mine with full throttle changes & box in S5 , pretty much all the time

When I have the wife in the car , or the roads are wet & slippy I drive the car a lot more relaxed but still change gear without lifting , but the throttle might be at anything between 10% - 100% pressed ... I have found after a while , when I next go for a full throttle redline change in say 3rd, it picks up a slight amount of slur ....... 10 minutes of thrashing & it reverts back to 'normal'


Assume this is the software 'learning' & adapting for driving style ? If it is, would love a method of overriding

In a lower setting like 1,2,3 you get a slow gear change that feels like a slur but thats its calm gear change.when you hit 4,5,6 setting these settings are ferocious so they throw the gear in a lot quicker 6 being traction off mode changes gear in 0.7th of a second hence the bang cos everything is thrown into motion not smoothly placed


There are some ecu software updates that teaches the gearbox to work out how worn the clutch is and take up bite point where the old software doesn't take this into account.that also will clear up SOME of the low gear judder problem

Engine ecu remap will do a great deal towards drivabilty no massive power gains but smooth delivery which has helped my gearbox!!

[CraigMillwardCroft]

In a lower setting like 1,2,3 you get a slow gear change that feels like a slur but thats its calm gear change.when you hit 4,5,6 setting these settings are ferocious so they throw the gear in a lot quicker 6 being traction off mode changes gear in 0.7th of a second hence the bang cos everything is thrown into motion not smoothly placed


There are some ecu software updates that teaches the gearbox to work out how worn the clutch is and take up bite point where the old software doesn't take this into account.that also will clear up SOME of the low gear judder problem

Engine ecu remap will do a great deal towards drivabilty no massive power gains but smooth delivery which has helped my gearbox!!

Who did your re-map then :-D

[Equinox]

Just make sure BMW dont get a sniff of a remap if you have a warranty as they wont cover the engine anymore !!

[adem.csl]

I used evolve they gave me 15bhp but the drivability is immense
Dma offer a 25bhp tune but its heard to be on the dangerous side(im not sure though)
http://forums.m3cutters.co.uk/showthread.php?t=10307

[thrashermax]

Done 20k miles in mine and always lift slightly. This gives me a smoother ride. Clutch has been fine... touch wood. It makes me feel better to lift… not shirts like Jim, alledgedly... Looking back at that sentence it looks weird.. touching wood and lifting shirts... Maybe I'll stop lifting..