6MT clutch engagement inconsistency

[G35POPPEDMYCHERRY]

Originally Posted by M3hf80

Update,

I had just came back from a nice long local drive to run some errands. I find that the car did not rev match when in sport or efficient mode after sitting in a drive thru (Maybe too much 1st gear?) and then I had switched the car into efficient mode which did not rev match either. Is this some type of soft ware issue? Or is this common after a long local drive? I'm actually starting to like the car without the rev match lol but I don't think this is normal.

The car wont rev-match first typically over 15mph...ie drive thru. you gotta understand the situations the car will rev-match and when it won't....this is most likely why you are getting clunky shifts; because you are expecting rev-matching and its not coming in at all

edit: theres two threads on this the fuckkk

[///M///]

It frickin' won't rev match if you are already in the correct rpm range. DOH!

If you are in 2nd gear at 20 mph (for I don't know why), then it won't rev match when you shift to 1.

Hope that makes sense.

[gatorfast]

Originally Posted by ///M///

It frickin' won't rev match if you are already in the correct rpm range. DOH!

If you are in 2nd gear at 20 mph (for I don't know why), then it won't rev match when you shift to 1.

Hope that makes sense.

That doesnt make sense...

[///M///]

Originally Posted by gatorfast

That doesnt make sense...

The whole point of rev match is to avoid rpm surge when you downshift to a lower gear at a higher speed.

But if you are doing really low speed in a higher gear (very low rpm), downshifting a gear really won't make a noticeable difference in rpm to initiate the rev match because the revs would hardly increase. The rev match is more pronounced when downshifting to a lower gear would cause the rpm to surge in the higher range.

Am having a hard time explaining this but the ones who understand this will get it.

Cheers.

[gatorfast]

Originally Posted by ///M///

The whole point of rev match is to avoid rpm surge when you downshift to a lower gear at a higher speed.

But if you are doing really low speed in a higher gear (very low rpm), downshifting a gear really won't make a noticeable difference in rpm to initiate the rev match because the revs would hardly increase. The rev match is more pronounced when downshifting to a lower gear would cause the rpm to surge in the higher range.

Am having a hard time explaining this but the ones who understand this will get it.

Cheers.

lol I understand what rev matching is and how gearing in manual transmissions work. I was just saying that your example of going 20mph in 2nd gear and then downshifting to 1st and insinuating that there will be no change in rpms is not accurate. The lower gears actually have a much larger spread than the higher gears, thus the difference in rpm between 1st and 2nd at any given speed will generally be greater than the difference in rpm between say 5th and 6th gear at a given speed.

Also, the car will rev match on downshifts no matter how insignificant the rpm difference is. It will always match the appropriate revs to the gear and speed.

[///M///]

Originally Posted by gatorfast

lol I understand what rev matching is and how gearing in manual transmissions work. I was just saying that your example of going 20mph in 2nd gear and then downshifting to 1st and insinuating that there will be no change in rpms is not accurate. The lower gears actually have a much larger spread than the higher gears, thus the difference in rpm between 1st and 2nd at any given speed will generally be greater than the difference in rpm between say 5th and 6th gear at a given speed.

Also, the car will rev match on downshifts no matter how insignificant the rpm difference is. It will always match the appropriate revs to the gear and speed.

You know exactly what I am trying to say but yet want to dissect it. I never said there is NO change. I said depending on the speed there is a minimal change but I was using that example loosely to point out to the OP that he may not be hearing it for such small changes.

I understand gears as well and didn't need the 5-6 overdrive comparison to the 1-2 gear gear change. I know and understand the gear ratios but I was hoping the OP gets the point though i suspect you have confused him further.

Nothing more to add here. Blabber along if you must...........

[CachacoF80]

Originally Posted by G4BR13L

And you experiencing this in all driving modes? Could be normal, if there is someone in your area that has the F8x with the 6MT you could meet up for a '2nd opinion'. Or have a friend drive it and ask their opinion. The clutch is heavy and you might not be used to it.

If the car has about 13k miles I doubt that there is something wrong with the clutch but then again it depends on how it was driven. Do you notice this only with the lower gears or with all 6 gears? Try to find a pattern or try to repriduce it like shifting from 6th to 5th @ 3000 RPM then at @ 2000 RPM, shift from 5th to 6th, ...

To be honest it could just be you as the driver, dunno how you drive but try for example to accelerate only after fully releasing the clutch instead of trying to dose between the clutch pedal and acceleration pedal. It also depends at what RPM you shift, maybe without realising it you shift differently when the engine is cold and once on temp you maybe still shift at too low RPM (?)

The clunkiness you feel could also be related to the driveshaft (lash).

Clutch is heavy? Please try my Mini S, I will develop stronger muscles!

OP I also vote for rev hang/rev match. Try in in Sport Plus.

[M3hf80]

Originally Posted by PureModelsOnly

OP I think you just have strange shifting habits so it's screwing up with the rev match system. Is it rev matching on down shifts consistently?

It's not rev matching on down shifts anymore, it comes back randomly. For example if I were to exit the freeway, it would match from 6 to 4 and then from 4 to 3 all of a sudden there wouldn't be any rev match.

[M3hf80]

Originally Posted by gatorfast

lol I understand what rev matching is and how gearing in manual transmissions work. I was just saying that your example of going 20mph in 2nd gear and then downshifting to 1st and insinuating that there will be no change in rpms is not accurate. The lower gears actually have a much larger spread than the higher gears, thus the difference in rpm between 1st and 2nd at any given speed will generally be greater than the difference in rpm between say 5th and 6th gear at a given speed.

Also, the car will rev match on downshifts no matter how insignificant the rpm difference is. It will always match the appropriate revs to the gear and speed.

That's my point, after paying close attention to how it drove last night, I had figured out the car would be rev matching perfectly then all of sudden there would be no rev match. Up shifts or downshifts, 0 rev matching at all. Then all of sudden it would come back. I have no trouble driving without rev match lol my point is I bought this car and the fact that it's having this malfunction is very concerning.

[M3hf80]

https://f80.bimmerpost.com/forums/sh....php?t=1246479

https://f80.bimmerpost.com/forums/sh....php?t=1192269

These 2 threads pretty much described exactly what I'm experiencing. I don't see a fix lol

[gatorfast]

Originally Posted by ///M///

You know exactly what I am trying to say but yet want to dissect it. I never said there is NO change. I said depending on the speed there is a minimal change but I was using that example loosely to point out to the OP that he may not be hearing it for such small changes.

I understand gears as well and didn't need the 5-6 overdrive comparison to the 1-2 gear gear change. I know and understand the gear ratios but I was hoping the OP gets the point though i suspect you have confused him further.

Nothing more to add here. Blabber along if you must...........

I didn't know what you were trying to say which is why I commented. You actually specifically said there will be no change/rev match if it is within some range.

Glad we are on the same page now.

[paliknight]

Id take it to the dealership to have it documented. They most likely will tell you there isnt anything wrong, but its good to have it documented just in case it worsens in the future.

[DFW_M]

10k miles here, in Dallas. Yesterday was 15F, 3 days ago was 80F, it was 100F in August, never experienced anything remotely unusual with the clutch. One of the best 6MT I have driven in the past 30 years

[BimmerMan33]

This may not pertain to OP issue but in general, I feel there is more rev hang designed on purpose in F8x M3 vs previous naturally aspirated M3s because if revs drop too quickly in a turbo motor, there would be more lag when getting back on throttle after shifting into next higher gear. So I guess having the revs drop more slowly would keep the turbo spinning, thereby reducing turbo lag....
Thoughts.....

[casschan86]

I have a 16 comp and my clutch feels different all the time. Cold and hot weather change the characteristics of how my clutch engages. I have gotten use to it. I have 40k on my M3 and the last time I went in for servicing I asked them to check it out and they said it was fine. Just drive it until you break it.

[clutchdj]

OP, how about starting with an I-Step update from the dealer. Do you have latest software?

[M3hf80]

Originally Posted by clutchdj

OP, how about starting with an I-Step update from the dealer. Do you have latest software?

No What is that? I took it into the dealer last week and I spoke with the master technician because I didn't want to drop my car off as I was afraid they weren't going to replicate the problem.

Took the technician for a spin and he saw it happen once, told me to wait because BMW had some event in Vegas and he's going to contact the head quarters and do some more research in regards to this issue. He said he's seen it before and hates the rev matching feature.

[hirev]

I have had o issues, and have 24,000 on the car. I notice when cold sometimes it feels like the clutch almost slips a bit, but it does not slip anywhere, just feels different, that is sometimes when cold. I live in sf bay area so it gets down to 35 degrees sometimes, but the car lives in a garage, only when it sits outside on a cold day.

I also skip shift....no discussion, i just have always done that on every car, and I have had 27 cars to date, mostly manuals.

[G35POPPEDMYCHERRY]

...u guys are honestly wasting your time with these "head shop people" go to a respected indy if u really want your problems fixed...but imo clutches are extremely temperamental; and I believe it has good and bad days; and thats just how it goes owning a manual nowadays.....all your problems are going to be rememdied as...

started car next day no faults found....checked clutch...ok....relubed door hinges...adjusted parking brake.....greeased axle...check problem...ok....washed and vaccumed....customer returns.....reset idrive...problem gone....

around and around it will go....dont get me wrong some shop foremans know their shit; but its getting sickening talking to mechanics at dealerships and they are baffled by simple problems a real mechanic fixes in two seconds...

[clutchdj]

Originally Posted by M3hf80

No What is that? I took it into the dealer last week and I spoke with the master technician because I didn't want to drop my car off as I was afraid they weren't going to replicate the problem.

Took the technician for a spin and he saw it happen once, told me to wait because BMW had some event in Vegas and he's going to contact the head quarters and do some more research in regards to this issue. He said he's seen it before and hates the rev matching feature.

It’s a factory firmware update that addresses any outdated software in certain and/or all modules. Definitely rule that out even though it sounds like you have a mechanical issue like a bad slave cylinder or glazed clutch. All speculation but I hope u get it sorted.

[M3hf80]

Originally Posted by clutchdj

It’s a factory firmware update that addresses any outdated software in certain and/or all modules. Definitely rule that out even though it sounds like you have a mechanical issue like a bad slave cylinder or glazed clutch. All speculation but I hope u get it sorted.

Idk if it's a mechanical issue, I think it's more of a firmware issue as it's not rev matching all the time and sometime it does it in Sport Plus lol.

[M3hf80]

***Update***

BMW doesn't know the issue, guess I'll keep driving the car until some serious shit pops up haha.