When downshifting with 6MT...

[pigwet]

In the economy and sport modes that employ rev matching, I notice that sometimes when I downshift the clutch does not fully engage until the last inch of travel or so. Vastly different from normal clutch engagement. This doesn't happen with every downshift that activates the rev matching - only sometimes. And yes, downshifting at the same speed will sometimes cause it and sometimes not. Can't pinpoint it yet. Notice it in 2nd and 3rd gears so far.

I don't regularly use these two drive modes, but when I do, I'll periodically get very rough downshifts because the behavior of the clutch completely changes.

Anyone else?

[solstice]

I've noticed it. First I thought it was the LSD not keeping up i certain scenarios ( very seldom ) and causing a jolt but now I'm not sure. I guess to never to linger on the clutch is a good thing ayway

[JoeFromPA]

Nope.

[mlc]

I notice if you stay on the clutch too long when down shifting you get that rough engagement but if your on and off of the clutch quickly it's smooth. I don't know if holding in too long lets the revs drop too far and engagement somehow suffers or what.

[Wei718]

Yeah, when you downshift you need to drop in into gear and release the clutch all the way and quick before the revs drops down

[Black Gold]

^^^^^

What they said

[solstice]

Thinking about it, it's just another trick in the bag we MT drivers use. When not rev matching we sometime gradually start the engine braking with gradual clutch engagement. With auto rev match it's trying to mix two things at once and the result is not what you expect. I.e the clutch should come out rather quickly when using auto rev match.

[Ging]

twin disc clutches and a soild driveline like the m4/m3 will make some random sounds

[jqmunro]

I noticed strange sounds when slowly engaging the even gears, especially 4th and 6th.

[pigwet]

Originally Posted by mlc

I notice if you stay on the clutch too long when down shifting you get that rough engagement but if your on and off of the clutch quickly it's smooth. I don't know if holding in too long lets the revs drop too far and engagement somehow suffers or what.

Great response. I think this is correct reason why. I can repeat this behavior.

I've owned 3 cars with rev matching and it didn't behave this way but for whatever reason the M3 does. I don't like rev matching, especially when you're just floating around town. I'm a little surprised there's a non-sport mode that doesn't rev match. Why rev match in economy? Just have a button that turns on and off rev matching. I keep in in sport plus all the time with my M buttons because of this.

[pigwet]

Originally Posted by solstice

Thinking about it, it's just another trick in the bag we MT drivers use. When not rev matching we sometime gradually start the engine braking with gradual clutch engagement. With auto rev match it's trying to mix two things at once and the result is not what you expect. I.e the clutch should come out rather quickly when using auto rev match.

Another great response.

[pigwet]

Originally Posted by jqmunro

I noticed strange sounds when slowly engaging the even gears, especially 4th and 6th.

I do as well. A slight rrrrrr.

[Black Gold]

Originally Posted by pigwet

Great response. I think this is correct reason why. I can repeat this behavior.

I've owned 3 cars with rev matching and it didn't behave this way but for whatever reason the M3 does. I don't like rev matching, especially when you're just floating around town. I'm a little surprised there's a non-sport mode that doesn't rev match. Why rev match in economy? Just have a button that turns on and off rev matching. I keep in in sport plus all the time with my M buttons because of this.

There should be an on off switch

But in confused why you wouldn't want to rev match in economy mode, or any mode? You should always rev match, whether done by yourself or by the computer in Eco/sport mode. That's how you are supposed to downshift.

[mtecnic]

So you can't turn it off?

I like to rev match myself