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      08-01-2013, 05:09 PM   #1
nugent
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DCT power shifting: bad?

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when upshifting I don't take my foot off the gas. with WOT this results in a very abrupt clunk when the gear slams into place, which scares passengers, which i like. does anyone know if this is detrimental to the clutch?
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      08-01-2013, 05:22 PM   #2
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I don't think it is although it feels like its harsh for the transmission
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      08-01-2013, 05:29 PM   #3
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Its not bad.... just think of the lag you would have with you let off the gas every time.
The clunk is how the DCT works. IMO I love it.
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      08-01-2013, 05:47 PM   #4
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BMW Performance Center instructors said keep the foot down while shifting. Put me in the "love the clunk" camp.
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      08-01-2013, 05:53 PM   #5
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Quote:
Originally Posted by nugent View Post
when upshifting I don't take my foot off the gas. with WOT this results in a very abrupt clunk when the gear slams into place, which scares passengers, which i like. does anyone know if this is detrimental to the clutch?
If you are drag racing how else would you do it? I do this when I get on entrance ramps for the freeway that are decently long. I can get to 100 real quickly on a couple of them and I do just what you describe.

In my experience, the passengers are more scared by the acceleration of the car than the clunk. If you don't have DTC on, the back end can get squirrelly in second and third gears. I was just doing this last night getting on to I -35 from a 50mph running start. I was in 3rd at the end of the entrance ramp and floored it from about 55-60. As I was shifting to fourth as described, the back end broke loose a bit. I cut across two lanes to the far left lane and I was at 100 when I got in. I was by myself though.
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      08-01-2013, 07:16 PM   #6
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I love the pops when shifting. Definitely leave the foot on the pedal.
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      08-01-2013, 07:36 PM   #7
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WOT gear changes - that what makes the M DCT great
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      08-02-2013, 12:39 AM   #8
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The ENTIRE point of dct is to provide uninterrupted power through changes which means you need your foot down. it is not harsh at all on the tranny as it is meant for that. In the m3 on S5/6 it is absolutely violent and just insanely makes the car slam into gear. It is absolutely awesome!
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      08-02-2013, 12:59 AM   #9
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S6 mode on the E60 M5 was far more violent. Felt like the diff was gonna fall off But don't lift, otherwise you lose the boost you just built up!
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      08-02-2013, 04:19 AM   #10
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What settings do you have on ?. I feel S2 is the sweet spot, if you dont like the thump on the gearchange. Sometimes i feel S3 unsettles the car a little, compared to S2.
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      08-02-2013, 10:04 AM   #11
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Ive never lifted my foot off when shifting, I always assumed with DCT that was the point. The DCT is nothing compared to the violence of SMGII in my e46, totally miss that.
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      08-02-2013, 11:07 AM   #12
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Dual clutch for a reason... Hammer on it!
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      08-02-2013, 12:06 PM   #13
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Why on earth would you lift between shifts? That would be defeating the whole concept of the DCT. Hammer down!
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      08-02-2013, 12:45 PM   #14
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dudes, I don't lift off. I wasn't asking who lifts off or not, just if anyone had any technical info on clutch/tranny wear. thanks to those who answered my question. m power.
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      08-02-2013, 01:18 PM   #15
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dont let off. it's an automated transmission. the faster the shift the longer the clutch will laster ironically.
slower shifts = more friction time which as a result causes heat which as a result burns clutches...
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      08-02-2013, 02:08 PM   #16
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Do you guys think that downshifting a lot is bad for the clutch/DCT?

I usually like to drive in S2 or S3 a lot and I like to downshift the DCT whenever I'm decelerating to a stop or a red traffic light because I like to hear the exhaust crack on each downshift with the Straightpipes. Does anyone think this is bad? My DCT seems fine and shifts smoother than ever.
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      08-02-2013, 02:27 PM   #17
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Quote:
Originally Posted by RPiM5 View Post
Do you guys think that downshifting a lot is bad for the clutch/DCT?

I usually like to drive in S2 or S3 a lot and I like to downshift the DCT whenever I'm decelerating to a stop or a red traffic light because I like to hear the exhaust crack on each downshift with the Straightpipes. Does anyone think this is bad? My DCT seems fine and shifts smoother than ever.
I always downshift however usually no lower than 3rd unless I will be #1 at the stop and feel the light will go green.
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      08-02-2013, 02:47 PM   #18
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Quote:
Originally Posted by AlphaAlpineM6
dont let off. it's an automated transmission. the faster the shift the longer the clutch will laster ironically.
slower shifts = more friction time which as a result causes heat which as a result burns clutches...
thank you. this is exactly the answer I was looking for.
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      08-02-2013, 03:04 PM   #19
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Quote:
Originally Posted by RPiM5
Do you guys think that downshifting a lot is bad for the clutch/DCT?

I usually like to drive in S2 or S3 a lot and I like to downshift the DCT whenever I'm decelerating to a stop or a red traffic light because I like to hear the exhaust crack on each downshift with the Straightpipes. Does anyone think this is bad? My DCT seems fine and shifts smoother than ever.
I love downshifting. I often do it into 1st as well just to hear the exhaust blip with the e-race.
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      08-02-2013, 03:19 PM   #20
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Quote:
Originally Posted by nugent View Post
thank you. this is exactly the answer I was looking for.
Absolutely correct about wear based on shift speed. I got to thinking about this. Isn't shift speed dependent on the drivelogic setting, not torque being passed through the transmission? I.e., 1 being the smoothest shift (the longest engagement) vs. 3 being the quickest (shortest engagement). So less wear on the clutches when using 3, but more work for the DCT pump. Vice-versa for 1.

When you lift, it doesn't change the shift speed, right? It just changes the torque on the input shaft. While there may be a minute difference in engagement speed (due to the potential increase clutch slippage) I'd think it'd be too short to be relevant, and, the torque would be passed to the inner input shaft immediately.

Either way...better to not lift. Another benefit is near constant power to the wheels which is what also a big plus for the DCT!
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      08-02-2013, 04:56 PM   #21
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Quote:
Originally Posted by M54ccibo
Quote:
Originally Posted by nugent View Post
thank you. this is exactly the answer I was looking for.
Absolutely correct about wear based on shift speed. I got to thinking about this. Isn't shift speed dependent on the drivelogic setting, not torque being passed through the transmission? I.e., 1 being the smoothest shift (the longest engagement) vs. 3 being the quickest (shortest engagement). So less wear on the clutches when using 3, but more work for the DCT pump. Vice-versa for 1.

When you lift, it doesn't change the shift speed, right? It just changes the torque on the input shaft. While there may be a minute difference in engagement speed (due to the potential increase clutch slippage) I'd think it'd be too short to be relevant, and, the torque would be passed to the inner input shaft immediately.

Either way...better to not lift. Another benefit is near constant power to the wheels which is what also a big plus for the DCT!
this. Thanks.
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      08-02-2013, 06:53 PM   #22
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Are you guys still holding the brake pedal down when stopped?
I remember in the e60 if you didnt press the brake pedal down when stopped the clutch disk would wear out.
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