agressive DCT change

[polly]

howzit guys

can someone out there in this beautifull world of ours explain. when you drive in manual mode in the DCT on the last setting the gearbox made a "thud" when changing on high revs, yet when the box is set in setting 1 or 2 the changes are smooth and can barley be felt. what causes this and is good to drive on the "fierce" setting all the time if i wish to keep the car for a long time?

thanks

[///M Rakete]

Originally Posted by polly

howzit guys

can someone out there in this beautifull world of ours explain. when you drive in manual mode in the DCT on the last setting the gearbox made a "thud" when changing on high revs, yet when the box is set in setting 1 or 2 the changes are smooth and can barley be felt. what causes this and is good to drive on the "fierce" setting all the time if i wish to keep the car for a long time?

thanks

The various Drivelogic settings determine the behavior of the transmission. Things like shift speed, clutch engagement speed, amount of allowed slippage, and in D mode shift and downshift RPM (gear holding) for curves and hills are dependent on the Drivelogic setting. The low ones, like 1 and 2 are smooth, like for your grandmother. The high ones like 5 and 6 bring out the full sporting capability of the transmission. The "thud" was your transmission doing a maximum or near-maximum performance shift. It is possible in "5" to chirp the tires. In "6" with DSC off you can really break the tires loose. I tend to drive in "D4" or with the M Drive button "S5". "S6" is good fun but requires a couple of additional steps (DSC off and Drivelogic to "6"). That's just the price of admission to allow the transmission to allow you to really drive the car to its fullest potential.

[polly]

is it possible to programme the car so that each time you start its in D4. at the moment its defaults to D2 each time you start.

[OC3]

Originally Posted by polly

howzit guys

can someone out there in this beautifull world of ours explain. when you drive in manual mode in the DCT on the last setting the gearbox made a "thud" when changing on high revs, yet when the box is set in setting 1 or 2 the changes are smooth and can barley be felt. what causes this and is good to drive on the "fierce" setting all the time if i wish to keep the car for a long time?

thanks

Yeah, was very surprised the first time I heard that "thud." I remember thinking, isn't that how SMG is supposed to sound/feel?

[SenorFunkyPants]

I stick with S2...I don't like the extra strain that the S4, S5 & S6 powershifts puts on the drivetrain plus it also unsettles the rear of the car which can make full throttle shifts during cornering somewhat "exciting"!

[JIO]

Originally Posted by polly

is it possible to programme the car so that each time you start its in D4. at the moment its defaults to D2 each time you start.

Nope it's fixed at D2 for the whole world except in the US where we get S3 as the default. You get D2 for the little extra gas mileage standard, and we get S3 for the little bit better emissions when the engine is cold. Go figure.

[kaykay]

Originally Posted by SenorFunkyPants

I stick with S2...I don't like the extra strain that the S4, S5 & S6 powershifts puts on the drivetrain plus it also unsettles the rear of the car which can make full throttle shifts during cornering somewhat "exciting"!

Ever try to downshift rev-match in S2? Pretty much impossible.

For driving in a manual style with barely and spirited driving and no downshift / reb-matching S2/S3 work well.

Nothing like a downshift rev-match in S5/S6

[mkoesel]

Originally Posted by JIO

Nope it's fixed at D2 for the whole world except in the US where we get S3 as the default. You get D2 for the little extra gas mileage standard, and we get S3 for the little bit better emissions when the engine is cold. Go figure.

I'm pretty sure all of North America gets the S3 default. Someone from Canada will hopefully correct me if I am wrong.

It is interesting what you say about fuel efficiency vs. emissions. Where did you get that info from?

[SenorFunkyPants]

Originally Posted by kaykay

Ever try to downshift rev-match in S2? Pretty much impossible.

Downshift, press accelerator pedal = rev matched downshift (if timed well).

[Stainless 45]

Pardon my ignorance (my car is yet to be ordered) but if the "D" settings are the shift aggressiveness, then what are the "S" settings? (Assuming no Idrive)

[e46e92love]

Originally Posted by Stainless 45

Pardon my ignorance (my car is yet to be ordered) but if the "D" settings are the shift aggressiveness, then what are the "S" settings? (Assuming no Idrive)

"D" Settings are the settings in "Drive" or "Auto" mode where the trans shifts for you. "S" mode is manual mode, where you shift the trans via the stick or the paddles behind the steering wheel.

Cheers,
e46e92

[Polarstar]

Originally Posted by JIO

Nope it's fixed at D2 for the whole world except in the US where we get S3 as the default. You get D2 for the little extra gas mileage standard, and we get S3 for the little bit better emissions when the engine is cold. Go figure.

After a few weeks of continually setting my car to D5 after starting, now it starts up at D5 every time.

[Chowster]

My Canadian spec car "remembers" my Dx setting - I believe it's key-specific. I leave it in D2 for routine family driving. The default when the car was new was D3.

However, the Sx setting is always S3 when starting the car up, and I switch it up to S4 each time.

[mkoesel]

Originally Posted by Polarstar

After a few weeks of continually setting my car to D5 after starting, now it starts up at D5 every time.

Actually, it has nothing to do with you teaching the car or anything like that.

What you are experiencing is this:

http://www.m3post.com/forums/showthread.php?t=416666

[James T. Kirk]

I love the THUD. My M-Drive is programmed to S5, but the THUD is controllable depending on how aggressively I'm timing my shifts. S3 and down is too smooth.

If I'm needing a soft ride (like when I'm driving my mother-in-law in the car), I just take it to D3 and go into a coma. As soon as she's out, I hit the M-button and I'm back to scaring pedestrians!

[lve2xlr8]

So would acceleration theoretically be faster from say 5-60 in s5 then it would be in s6 due to less wheel spin on the 1-2 shift?

[mkoesel]

Originally Posted by lve2xlr8

So would acceleration theoretically be faster from say 5-60 in s5 then it would be in s6 due to less wheel spin on the 1-2 shift?

If you turn off DSC in S5 then you'll get no better time than S6 (where DSC must necessarily be off). If you leave DSC on, you will almost certainly get DSC intervention and poor acceleration.

So, the question becomes does S5 in MDM give better acceleration than S6? The answer to that would depend greatly on available traction (road surface condition, road temperature, tire age), but it's not impossible that S5 + MDM would yield the better result in some situations.

EDC, if spec'd on the car, could also play a factor.

[Polarstar]

Originally Posted by mkoesel

Actually, it has nothing to do with you teaching the car or anything like that.

What you are experiencing is this:

http://www.m3post.com/forums/showthread.php?t=416666

Does it really matter why it's starting in D5? That's my preferred setting. I use S5 with the M button. Actually I start the car in the garage, it's in P, then I put it in R, with foot on brake, old habit, just seems right, then I back out, then move shift to the right, with foot on brake, and it's in D5, with the power button on, and then I drive away. So if there's a bug in the software, does it matter, since the car is behaving as I like? My car is a 2011, May build. I'll test the whole brake on/off when shifting thing if you want....

[sensi09]

I do wish S2 or S3 would offer rev-matching....I don't quite understand why it doesn't. Sure you can get a blip by hitting the gas, but what if you're on the brakes. Sure you could heel-toe, but that kinda defeats the purpose.

[Mr.Bimmer]

Originally Posted by polly

howzit guys

can someone out there in this beautifull world of ours explain. when you drive in manual mode in the DCT on the last setting the gearbox made a "thud" when changing on high revs, yet when the box is set in setting 1 or 2 the changes are smooth and can barley be felt. what causes this and is good to drive on the "fierce" setting all the time if i wish to keep the car for a long time?

thanks

I believe I know what you are describing. Does this happen primairly right around the redline, just shy of the redline? I have never been able to experience that thud anything short of 8k rpm's in the idential driving settings you are describing

[ss134]

I drive in S5 all of the time - you only get aggressive shifts if you shift near the redline, if you are not driving in a 'spirited' fashion then upshifting earlier will still give you a smooth shift if that is what you want.

[kaykay]

I'm trying to decide between D3 and D4 for automatic city/traffic driving... Leaning towards D3.

Haven't really driven this thing in D1/D2 so I have not idea what goes on in that range (probably super smooth upshifts with wretched slow downshifts).

I also don't see the point of S1, S2 or S3 driving when the downshifts are wretchedly slow in those modes, sure the upshifts are smooth, but maybe you're using these modes for grandma-mode and not downshifting much.