German Car Zone

Just_me · 03-26-2008, 10:36 AM

BimmerPost - BMW Forums - View Single Post - First driving reviews of M3 M-DCT / M-DKG transmission!

First post community-manager:
We wanted to allow you getting an idea of the experience the new M-DCT with Drivelogic provides as early as possible, hence the mods of the MPW in advance had the opportunity of a co-drive on the test track.

Let me add a comment to the mentioned "torque oversteer":
Simplified this means: When performing an upshift, the engine's still revving too high for the next ratio.
In case of a quite fast clutch-in (M-DCT is able to do so), the engine gets decelerated and thus stored energy is set free, this means an additional moment to the drive train, the car makes a feelable and positive jerk forwards. This also means a measurable advance in acceleration (aswell as stirring ones blood up).
On the other hand you can still choose a lower drivelogic setting to enjoy the full comfort, in that case the gearchanges appear accordingly smooth.

Enjoy the reviews.

Regards, CM

Second post, first driving member:

My first encounter with M-DCT:
I've read some information on the M-DCT both here in the MPW and in some car mags, but no meaningful driving test/impression yet.
As a die hard SMG fan - who's currently driving an MT - I was interested in the technical description. The mentioned possibilites/options [of the DKG] were quite impressive to me. But I still couldn't imagine driving an M equipped with a double clutch transmission, a technology known from VW group. That was a mismatch in my opinion. So I was anxious to (co)ride in an E90 M3 with M-DCT, which has been offered to me yesterday.
Just like SMG there are 11 different drive modes: 5 auto and 6 manual modes.
We started the drive in S4 (manual mode). In that mode there are short, noticeable shift interruptions, but no traction interruption during acceleration, just like SMG. Visually spoken it's like the SMG with the only difference that the head only nods rearwards due to the missing traction interruption. Down-shifts caused a big grin on my face due to the (already known from SMG) throttle blip, the V8's trumpeting. In S5 and S6 gear changes are unbelievably fast, though quite noticeable, but it doesn't produce jerks in such a brutal manner the SMG did. Gear changes up to 3rd gear in the said modes produce a short slip of the rear tires. There's also a launch control which works like the SMG's. The BC display shows a checkered flag, the launch is very brute (meant in a good way) with short gear change jerks. We didn't test the auto mode that much. D1 and D2 are like the Audi ad claim, shifting almost imperceptible and fast 'till 7th gear under hard acceleration. Compared to SMG there's also a 'creep' mode, which means that the car moves slowly like a conventional auto, that's surely helpful for parking and traffic situations.
My short vedict is that my apprehension the DKG would be an mushy version of SMG didn't turn out to be true, it's rather a true evolutional step. Very well done!
I'm sure driving M-DCT myself for the first time will be great fun. Only then I'll be able to form an final opinion and tell if the impressions I got from the co-drive are true.

Third post, second driving member:
Yesterday I aswell had the pleasure of having a co-drive in a new M3 with M-DCT. Sure, it would have been better to drive the car myself, but we had to accept the fact that customers aren't allowed to drive test cars. On the other hand the test drivers did every test we wanted them to do, so these reviews are authentic nonetheless and give an impression of the DCT's functionality.

Initially I had problems understanding what a gear change "without torque interruption" means. While riding in the test car I thought "What? That's just like SMG." On inquiry this has been explained to me again. Thus guys, no need to fear that the rev counter moves up to 8k rpm and the tach from odd to 270 kph without noticing any gear changes. And that's a good thing, elsewise some joy of driving would be missing. A shift must be felt, so you know when the next gear's engaged. Gearchanges are fast and precise with DCT. In S6 the DCT enables so called "torque oversteer" during a gear change. Not everybody might like that and it should be taken with a pinch of salt:
Especially during cornering on wet and bumpy roads this can lead to the rear wheels losing grip. In combination with the fact that S6 is only available with DSC disengaged this might result in an unintentional trip to the botany.

I don't know if that will be the same for the series version since the test cars' software version might not be the same. Anyway I'd like to mention that S6 only can be recommended to people who know what they're doing. All the other drivelogic modes work perfectly and provide an absolutely harmonious driving experience in combination with DSC.Compared to SMG there's no head nod forwards, only the jerk of the car and thus a head nod backwards.

Furthermore there are some additional functions that have been improved over SMG. To mention are:

1. Auto parking lock
DKG now allows to turn off the car no matter in which mode it is. An automatic parking lock is activated as soon as the key is ejected. Thinking of "engaging first gear when turning off" or "starts only when in Neutral" is a thing of the past.

2. "Creep mode"
While parking and when in heavy traffic the new DKG supports you more than ever. When the car has come to a complete stop you just have to carefully touch the gas pedal and the car starts moving slowly. This works both forwards and backwards and is thus also good for parking.

3. "Hill start modus"
When one has to start on a hill DCT (unlike SMG) is also helpful. With SMG you had to engage the emergency brake. With DCT the brake stays engaged for 3 or 4 seconds after you've released it, which leaves enough time to engage the gas pedal. Only then the brakes are releasing and the car starts moving forwards without rolling back. If you need longer than 4 seconds the car rolls back.

4. Auto mode
A big improvement. DCT changes gears reliable and guesses the right gear better than the SMG did in auto mode. Whereas I never would use the auto mode of SMG because it used to change gears randomly the DCT's auto mode is something I could like. This may be helpful for boring drives on a speed limited section of the Autobahn.

5. Drivelogic modes
On the SMG I'd have prefered the modes S2 or S3 whereas with DCT I'd rather tend to chose S4 or S5. The gear change jerks occuring on the rear axle the SMG used to have are also a thing of the past with DCT. Gear changes are forceful and don't give you the feeling that the rear axle is ripped out of its mountings.

6. Clutch wear
The fact that M-DCT uses two oil-cooled wet clutches could have an good impact on clutch wear. Sure, in case of an change you have to replace two clutches, but this should also mean they're double as durable. Even sport starts with the launch control aren't that bad for the clutch like they would be to a conventional dry clutch. Anyway it should be mentioned that a launch control does not only affect the clutch, but also other drive train parts like drive shaft, rear axle aswell as tires. So it still should be taken with care.

Verdict:
In my opinion the M-DKG is nothing entirely new, but a better SMG. Sure, the whole transmission concept is new and a different technology, but to an BMW driver it's a better SMG and continues where SMG's development has stopped. In any case, if I buy an new M it will be equipped with DCT.

Who likes SMG will love DCT!

Best regards, south

Just_me · 03-26-2008, 03:05 PM

South translation, easier to understand, better english

First post community-manager:
We wanted to allow you getting an idea of the experience the new M-DCT with Drivelogic provides as early as possible, hence the mods of the MPW in advance had the opportunity of a co-drive on the test track.

Let me add a comment to the mentioned "torque oversteer":
Simplified this means: When performing an upshift, the engine's still revving too high for the next ratio.
In case of a quite fast clutch-in (M-DCT is able to do so), the engine gets decelerated and thus stored energy is set free, this means an additional moment to the drive train, the car makes a feelable and positive jerk forwards. This also means a measurable advance in acceleration (aswell as stirring ones blood up).
On the other hand you can still choose a lower drivelogic setting to enjoy the full comfort, in that case the gearchanges appear accordingly smooth.

Enjoy the reviews.

Regards, CM

Second post, first driving member:

My first encounter with M-DCT:
I've read some information on the M-DCT both here in the MPW and in some car mags, but no meaningful driving test/impression yet.
As a die hard SMG fan - who's currently driving an MT - I was interested in the technical description. The mentioned possibilites/options [of the DKG] were quite impressive to me. But I still couldn't imagine driving an M equipped with a double clutch transmission, a technology known from VW group. That was a mismatch in my opinion. So I was anxious to (co)ride in an E90 M3 with M-DCT, which has been offered to me yesterday.
Just like SMG there are 11 different drive modes: 5 auto and 6 manual modes.
We started the drive in S4 (manual mode). In that mode there are short, noticeable shift interruptions, but no traction interruption during acceleration, just like SMG. Visually spoken it's like the SMG with the only difference that the head only nods rearwards due to the missing traction interruption. Down-shifts caused a big grin on my face due to the (already known from SMG) throttle blip, the V8's trumpeting. In S5 and S6 gear changes are unbelievably fast, though quite noticeable, but it doesn't produce jerks in such a brutal manner the SMG did. Gear changes up to 3rd gear in the said modes produce a short slip of the rear tires. There's also a launch control which works like the SMG's. The BC display shows a checkered flag, the launch is very brute (meant in a good way) with short gear change jerks. We didn't test the auto mode that much. D1 and D2 are like the Audi ad claim, shifting almost imperceptible and fast 'till 7th gear under hard acceleration. Compared to SMG there's also a 'creep' mode, which means that the car moves slowly like a conventional auto, that's surely helpful for parking and traffic situations.
My short vedict is that my apprehension the DKG would be an mushy version of SMG didn't turn out to be true, it's rather a true evolutional step. Very well done!
I'm sure driving M-DCT myself for the first time will be great fun. Only then I'll be able to form an final opinion and tell if the impressions I got from the co-drive are true.

Third post, second driving member:
Yesterday I aswell had the pleasure of having a co-drive in a new M3 with M-DCT. Sure, it would have been better to drive the car myself, but we had to accept the fact that customers aren't allowed to drive test cars. On the other hand the test drivers did every test we wanted them to do, so these reviews are authentic nonetheless and give an impression of the DCT's functionality.

Initially I had problems understanding what a gear change "without torque interruption" means. While riding in the test car I thought "What? That's just like SMG." On inquiry this has been explained to me again. Thus guys, no need to fear that the rev counter moves up to 8k rpm and the tach from odd to 270 kph without noticing any gear changes. And that's a good thing, elsewise some joy of driving would be missing. A shift must be felt, so you know when the next gear's engaged. Gearchanges are fast and precise with DCT. In S6 the DCT enables so called "torque oversteer" during a gear change. Not everybody might like that and it should be taken with a pinch of salt:
Especially during cornering on wet and bumpy roads this can lead to the rear wheels losing grip. In combination with the fact that S6 is only available with DSC disengaged this might result in an unintentional trip to the botany.

I don't know if that will be the same for the series version since the test cars' software version might not be the same. Anyway I'd like to mention that S6 only can be recommended to people who know what they're doing. All the other drivelogic modes work perfectly and provide an absolutely harmonious driving experience in combination with DSC.Compared to SMG there's no head nod forwards, only the jerk of the car and thus a head nod backwards.

Furthermore there are some additional functions that have been improved over SMG. To mention are:

1. Auto parking lock
DKG now allows to turn off the car no matter in which mode it is. An automatic parking lock is activated as soon as the key is ejected. Thinking of "engaging first gear when turning off" or "starts only when in Neutral" is a thing of the past.

2. "Creep mode"
While parking and when in heavy traffic the new DKG supports you more than ever. When the car has come to a complete stop you just have to carefully touch the gas pedal and the car starts moving slowly. This works both forwards and backwards and is thus also good for parking.

3. "Hill start modus"
When one has to start on a hill DCT (unlike SMG) is also helpful. With SMG you had to engage the emergency brake. With DCT the brake stays engaged for 3 or 4 seconds after you've released it, which leaves enough time to engage the gas pedal. Only then the brakes are releasing and the car starts moving forwards without rolling back. If you need longer than 4 seconds the car rolls back.

4. Auto mode
A big improvement. DCT changes gears reliable and guesses the right gear better than the SMG did in auto mode. Whereas I never would use the auto mode of SMG because it used to change gears randomly the DCT's auto mode is something I could like. This may be helpful for boring drives on a speed limited section of the Autobahn.

5. Drivelogic modes
On the SMG I'd have prefered the modes S2 or S3 whereas with DCT I'd rather tend to chose S4 or S5. The gear change jerks occuring on the rear axle the SMG used to have are also a thing of the past with DCT. Gear changes are forceful and don't give you the feeling that the rear axle is ripped out of its mountings.

6. Clutch wear
The fact that M-DCT uses two oil-cooled wet clutches could have an good impact on clutch wear. Sure, in case of an change you have to replace two clutches, but this should also mean they're double as durable. Even sport starts with the launch control aren't that bad for the clutch like they would be to a conventional dry clutch. Anyway it should be mentioned that a launch control does not only affect the clutch, but also other drive train parts like drive shaft, rear axle aswell as tires. So it still should be taken with care.

Verdict:
In my opinion the M-DKG is nothing entirely new, but a better SMG. Sure, the whole transmission concept is new and a different technology, but to an BMW driver it's a better SMG and continues where SMG's development has stopped. In any case, if I buy an new M it will be equipped with DCT.

Who likes SMG will love DCT!

Best regards, south

Just_me · 03-26-2008, 03:16 PM

I like the fact that there are still jerkiness in manual mode in the fastest setting (S6). Still a race inspired gearbox.

Another good thing is that in automatic mode the gearchanges are smoother than SMG. And DCT find the "best gear" better than SMG did.

Tarek · 03-26-2008, 04:04 PM

Btw is there test of the M3 with the new DCT yet?

Just_me · 03-26-2008, 04:24 PM

Quote:

Originally Posted by Tarek

Btw is there test of the M3 with the new DCT yet?

no, this is the first.

dr Dunkel · 03-26-2008, 07:48 PM

This bodes very well for the new M3. Just like with the E46 the gearbox will divide the enthusiasts but this time it will be harder for the stick-guys to stick (haha) with the manual gearbox.

bmer · 03-26-2008, 07:58 PM

Quote:

Originally Posted by dr Dunkel

This bodes very well for the new M3. Just like with the E46 the gearbox will divide the enthusiasts but this time it will be harder for the stick-guys to stick (haha) with the manual gearbox.

True, I'm usually all for a manual but in M3's case I would definitely take the DCT.

S'Pimp · 03-27-2008, 02:05 PM

Beware!
these folks talk only about their impressions on passenger seat.
the car is driven by a BMW-testdriver
btw - new gearbox is a leap forward

NarutoRamen · 03-27-2008, 02:28 PM

I'm waiting for a review from a reputable magazine about the new gearbox. This is nice, but since he wasn't the one who drove it it kind of negates the review.

tobajara · 04-18-2008, 03:30 PM

YouTube - m3e90board.com testdrive of BMW M3 E92 DKG Double Clutch 1/2

YouTube - m3e90board.com testdrive of BMW M3 E92 DKG Double Clutch 2/2

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First impressions: new DCT gearbox