DCT question (gear whine)

[snakeslayer]

I drove my first E92 M3 yesterday, and intend to purchase one in the next couple of months. I have always been a manual transmission guy, but am leaning towards trying the DCT. My previous M3 was an E46 with the manual (I drove the SMG and absolutely disliked it). Yesterday was the first time I had driven one with the DCT.

The one thing I noted on that car was that at low RPMs (under 2K) I could hear just a hint of gear whine in it. It was soft enough that even the fan blowing would have probably drowned it out, but my ears are very tuned in for that sort of noise. Is this a normal characteristic for the DCT?

[Ctm309]

Normal, mine has a bit more in 5th.

[Vrrooom3]

Could be because of the way the gears are cut. Straight cut gears wine more but are stronger so since the transmission shifts itself BMW (or Getrag) may have gone with straighter gears. (just a theory)

[snakeslayer]

Originally Posted by Ctm309

Normal, mine has a bit more in 5th.

4th and 5th were the two selections I noted it in.

[Chako]

I think this is normal.
My 6MT has the same whine at partial throttle in the higher gears (low RPM ranges). Goes away at WOT. Was told it's normal.

If I were to choose the car again, I would take either 6MT or DCT equally nowadays. The 6MT is more involving but to be honest, it's not the best 6MT and although it doesnt ruin the experience as a whole, it's the weakest part of the car IMO. (I might get SSK to try and remedy). The DCT is quite good when I testdrove; much quicker than I can shift, and almost* as much fun.

[snakeslayer]

Originally Posted by Chako

I think this is normal.
My 6MT has the same whine at partial throttle in the higher gears (low RPM ranges). Goes away at WOT. Was told it's normal.

If I were to choose the car again, I would take either 6MT or DCT equally nowadays. The 6MT is more involving but to be honest, it's not the best 6MT and although it doesnt ruin the experience as a whole, it's the weakest part of the car IMO. (I might get SSK to try and remedy). The DCT is quite good when I testdrove; much quicker than I can shift, and almost* as much fun.

Yes, I am wondering if I will miss having a traditional manual. Automatics bore me as a rule, and I only buy them in trucks. But the DCT seems worth a shot and I know I certainly can not shift as fast as it can.

[mkoesel]

Originally Posted by Vrrooom3

Could be because of the way the gears are cut. Straight cut gears wine more but are stronger so since the transmission shifts itself BMW (or Getrag) may have gone with straighter gears. (just a theory)

Gears are helical just like a typical manual or other transmission intended for street use.

[Chako]

Originally Posted by snakeslayer

Yes, I am wondering if I will miss having a traditional manual. Automatics bore me as a rule, and I only buy them in trucks. But the DCT seems worth a shot and I know I certainly can not shift as fast as it can.

If it's my DD I would lean towards the DCT, if it's not I would lean towards the 6MT. I would miss the 3rd pedal a little but not too much.

Your thread motivated me to start a thread about my 2 biggest 'annoyances' regarding the 6MT: http://www.m3post.com/forums/showthread.php?t=482642

[SenorFunkyPants]

Nice pic...the clutch packs look funky.

[erichui323]

I have the same problem, are you sure is normal. My 6MT has the same whine at partial throttle in the higher gears (low RPM ranges).

[erichui323]

My 6MT has the same whine at partial throttle in the higher gears (low RPM ranges). is it normal?

Originally Posted by Chako

I think this is normal.
My 6MT has the same whine at partial throttle in the higher gears (low RPM ranges). Goes away at WOT. Was told it's normal.

If I were to choose the car again, I would take either 6MT or DCT equally nowadays. The 6MT is more involving but to be honest, it's not the best 6MT and although it doesnt ruin the experience as a whole, it's the weakest part of the car IMO. (I might get SSK to try and remedy). The DCT is quite good when I testdrove; much quicker than I can shift, and almost* as much fun.

[crabman]

Originally Posted by snakeslayer

I drove my first E92 M3 yesterday, and intend to purchase one in the next couple of months. I have always been a manual transmission guy, but am leaning towards trying the DCT. My previous M3 was an E46 with the manual (I drove the SMG and absolutely disliked it). Yesterday was the first time I had driven one with the DCT.

The one thing I noted on that car was that at low RPMs (under 2K) I could hear just a hint of gear whine in it. It was soft enough that even the fan blowing would have probably drowned it out, but my ears are very tuned in for that sort of noise. Is this a normal characteristic for the DCT?

Depends on how warmed up the car is too, quite a bit more whine when it is cold.

I got the DCT after a lifetime of sticks, even my trucks have been sticks. Like you I wanted to give one of these fancy sequentials a try to see what it was all about. After a month of ownership I'm not sure that it was the right choice or not. As a lifelong manual guy I don't find manuals involving in normal driving. Sounds weird but I when I drive a stick outside of the initial getting to know period I don't think about, I don't try. I go up the gears, down the gears, stop, start, hands and feet just do their thing. Its when I'm pushing it that I get most of my satisfaction from driving a stick. Oddly with the DCT I have found myself "learning" to shift it, I'm paying attention. Shifts can be much smoother or rougher, etc depending on how you use the throttle. The novelty aspect is sure to wear off and for me already is but the concept that you just slap paddles is not correct, you have to learn to shift the DCT in order to get the most out of it.

I haven't used drive mode much but have come to learn that I can control the shift points and firmness somewhat with subtle changes in throttle position in a way that cant be done with a standard slushbox or at least one I have encountered. Not much else to say about drive mode other than the obvious to most people but a revelation to me. I think it was about a week before I was stuck in stop and go traffic out on the freeway and thought "hmmmm, lets try drive mode". It really is pretty nice slapping it over and cranking the stereo in such situations.

Overall I don't think most stick people are going to hate the DCT, it is much better in terms of involvement than a slushbox. I would think the stick guys who are most likely to be happy with choosing it are the ones that have to commute in heavy traffic. The ones least likely to be happy those who own this as a fun car and do the no fun driving in another. For me now a month in I suspect I'll likely go back to a stick. I don't have anything bad to say about the DCT but its at its best when you regularly have good reason to take advantage of its auto mode and I don't.