Getting greasy with BMW's M Dual Clutch transmission
click above for more high-res images of the BMW M3 Convertible
Honestly, we couldn't care less about BMW's recent introduction of the M3 convertible. What did get our attention is the long-awaited addition of a seven-speed dual-clutch gearbox on every vehicle donning an M3 badge.
The M DKG setup uses two clutches with 1st, 3rd, 5th and 7th (plus reverse) on one shaft and 2nd, 4th and 6th on the other. Both clutches are oil-cooled and, like the systems offered by other manufacturers, the dual-clutch setup offers both quicker shifts and better fuel economy.
In typical BMW fashion, you'll have the option to select several different drive settings both in automatic and manual mode. Five shift programs can be selected when running around in the standard work-a-day auto setting, while six shifting selections can be made in manual, including the always entertaining launch control setting.
There's no doubt that all of this will be an improvement over BMW's SMG transmission, but we'll have to wait until next month to see how the DKG setup handles the rigors of track duty, the daily grind and performance tests.
BMW's full press release is posted after the jump.
Gallery: 2009 BMW M3 Convertible
PRESS RELEASE
New seven-speed transmission adds performance, even more refinement to BMW M3
Incomparably smooth, silky gearshifts in the blink of an eye, improved fuel economy and reduced emissions are just some of the benefits of the ground-breaking seven-speed M double-clutch transmission with Drivelogic that has been developed by BMW M GmbH for the new BMW M3 Coupé, Sedan and Convertible.
On top of these benefits, the new M double-clutch transmission with Drivelogic is able to produce lightning-fast gearshifts that result in accelerative abilities exceeding those of the six-speed manual transmission version of the new BMW M3.
The BMW M3 Coupé with M double-clutch transmission with Drivelogic is able to accelerate from zero to 100km/h in just 4.6 seconds, or 0.2 of a second faster than the manual six-speed version, while returning an average fuel consumption of 11.9 litres/100 km.
As the world's first seven-speed double-clutch gearbox developed for a high-torque, high-speed powerplant, the new BMW M double-clutch transmission with Drivelogic simultaneously lifts refinement and efficiency to new levels while providing the driver with a wide range of options that adapt the system to the needs of the moment.
The new transmission offers as many as eleven driver-selectable electronically controlled driving program choices.
These include five shift programs in the fully automatic mode and six in manual mode, and are supplemented by a selectable Launch Control program that provides blistering off-the-line acceleration where the power from the 309 kW, 4.0-litre V8 M3 engine is transferred with maximum effect to the road.
The heart of the new BMW transmission is the double clutch system that acts to smooth out gearshifts to the point that they are often only discernible by watching the rise and fall of engine rpm on the M3's tachometer.
Each oil-cooled wet clutch activates its own set of ratios - one is used for first, third, fifth and seventh gears, as well as reverse, while the other looks after second, fourth and sixth gears.
Gearshifts are effected by the disengagement of one clutch and the engagement of the other, moving seamlessly from the ratio in use to the next, preselected ratio.
The fact that the next ratio is preselected and engaged merely by activation of the clutch is the secret behind the amazingly smooth and efficient transition from gear to gear.
Combined with the BMW Drivelogic system that, as well as offering the driver a choice of seven specific operational modes, is also able to determine the appropriate mode according to the current driving style, the new transmission's multi-faceted nature allows it to offer anything from rapid-fire F1-style shifting to smooth, luxurious behaviour suited to relaxed boulevard cruising.
The new M double-clutch transmission with Drivelogic also incorporates a Low Speed Assistant mode that operates when manoeuvring at speeds less than 5 km/h to significantly increase the smoothness and degree of accelerator control available to the driver.
Gradient detection also means that the new M double-clutch transmission with Drivelogic is able to determine the appropriate ratios when travelling up or down hills.
This avoids the "hunting" between gears so often experienced in regular automatics when travelling on undulating roads, while the appropriate selection of lower gears on downhill gradients helps maintain road speed by using the braking power of the engine.
The new M double-clutch transmission with Drivelogic also offers the driver the choice of sequential operation via a sports selector lever in the centre console, or solid aluminium F1-style paddles on the steering wheel - right side for upshifts, left side for downshifts.
The range of shift programs available to the driver means it is possible for the M3 to behave with the grace and aplomb of a luxury car, or with the knife-edge rapidity and precision of a racecar - or anything in between.
In fully automatic D mode, the driver can select from five Drivelogic programmes that regulate both the gearshift speeds and the change points right through to the D5 mode where the engine is stretched close to its maximum rpm - depending on throttle position - on upshifts. In D1 mode, the M3 with M double-clutch transmission with Drivelogic is able to start off in second gear to help avoid wheelspin in slippery conditions.
In manual mode, six different Drivelogic programmes allow a similar range of characteristics, with the added driver control provided by the ability to choose shift points manually. In S6 mode, the drive can also activate launch control by holding the shift lever in the forward position.
In keeping with the overtly dynamic abilities of the new BMW M3, the M double-clutch transmission with Drivelogic, as well as being designed for engine speeds as high as 9,000 rpm, is also able to maintain correct operating temperatures even in the most extreme conditions - including racetrack operation - through its integration with the engine's cooling system as well as the fact it also incorporates its own oil/air cooler.
The transmission's interconnection with the engine cooling system also means a quicker temperature rise from startup, which contributes to reduced frictional losses and lower fuel consumption during the warm-up phase.
Faster shifting, smoother, and contributing even more to fuel economy and minimalised exhaust emissions, the new M double-clutch transmission with Drivelogic raises the bar for sophisticated, high-performance motoring to new heights.
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Reader Comments (Page 1 of 2)
Jim Brooks 9:23AM (4/27/2008)
I own a '04 M3 with SMG II. Have had it since the fall of '03. It is a supurb car but there is significant learning curve in using the SMG. Once mastered, the SMG is excellent. Better than any manual I've ever driven. I'm disappointed that BMW didn't come up with something equivalent to the new '09 Nissan GT-R that does 0 to 60 in 3.2 seconds.
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Jack 8:44PM (5/20/2008)
Very much looking forward to driving Dual clutch box. I had an '02 M3 with SMG and I loved it. Yes, it banged the gears, but it was so much fun and I never had to worry about missing a gear. Although after 40k miles the axles developed a "noise" and the clutch started slipping, so I hope the DMG will be as fun but have a longer life. I agree with the comments that having a true manual box provides the most feel, but as cars get faster and faster, the more time hands are on the steering wheel the better. I've not heard a single F1 driver complain about having paddle shifting. As for torque converter boxes, they have all improved vastly in the past five years. The 7-speed auto in my SLK 55 AMG shifts very fast (but it does have flaws). The new Jaguar XKR ZF automatic is just fantastic - even throttle blips on downshifts. I guess after racing shifter karts for a while I'm just accustomed to shifting with my hands on the wheel and using my left foot for braking; not for depressing a clutch pedal.
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tankd0g 3:38PM (1/17/2008)
I thought BMWs SMG was already one of the best, what's wrong with it?
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zamafir 3:49PM (1/17/2008)
Nothing, this is a slush box, no clutch pedal.
cc 4:10PM (1/17/2008)
I'm a manual fan but this sounds pretty fun to drive... and by the way, I think "slushbox" as slang for an auto originally came from the fact that most traditional autos use a torque converter, which actually uses fluid to transfer the engine's power to the wheels... this is in no way a "slushbox" by that definition.
Spike 4:02PM (1/17/2008)
The BMW ones were considerably slow compared to the competition.
SPF 4:03PM (1/17/2008)
@zamafir
I don't think SMG has a clutch pedal.
tankd0g 4:06PM (1/17/2008)
So they tweaked the SMG and gave it a new name. BMW is going to run out of acronyms soon.
JD 6:04PM (1/17/2008)
I heard lots of complaints about SMG from several publications, like jerky shifts and lame behavior in auto mode. It's not a slushbox, that's an auto. This is an automated manual. And they also built this from the ground up, it's not a revision of SMG. Given how slick I've heard Audi's (Porsche's?) dual clutch system is, I look forward to seeing how the BMW system compares.
One thing I've never, ever heard is how long the clutches last in these dual clutch systems, or how much it is to replace them when they do wear out. It seems they would last a long time without a human operator to murder them, but I think it's still a valid concern. Of course, if you nurse the clutch right, it can last a (very) long time. My grandfather has an '85 BMW 325e 5 speed, and he had the original clutch in that car for 18 years.
Mi key 3:48PM (1/17/2008)
That great now, BMW and Bugatti both have 7sp DSG
Is it really faster tha a 6sp manual? That Awesome!
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Dan 3:58PM (1/17/2008)
Lack of a clutch pedal does not a slush box make....lack of a clutch does. The slush comes from an automatic's torque converter. SMG's, DSG's and "Dual Clutch" transmissions all have clutches. But you probably already knew that.
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PAT 3:59PM (1/17/2008)
I haven't driven an M3 with these new advanced transmissions, but it seems like you loose some of the fun and connection you get with a manual. As mentioned before, can a person really notice the decrease in shift time? The increase in fuel economy is a plus, though.
Just seems like it is getting out of control, adaptive driving modes and so forth. A human being can change the driving mode anytime he/she wants, without computer assistance.
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Jason H 5:05PM (1/17/2008)
No, the new DKG DCT is a completely different and improved design, not an AMT like SMG at all, IYKWIM.
And to the comment below about manuals 'feeling' better-- DCT transmissions have very similar inertia to manual transmissions, and provide the nearly same direct feeling as a manual, depending on some control strategies for the clutch engagements. But in an M3 or similar car, you can be sure that it will be biased toward the sporty feel and therefore should be every bit as rewarding on the 'feel' aspect- not slipping feeling, immediate engagements, etc. It is clearly the best solution to filling in the space between the engine and the driven axles of any road car intended for sporting use.
Henry 4:19PM (1/17/2008)
No this is different than the SMG. The SMG was a regular 6 speed manual transmission with a single computer controlled clutch. It was literally a transmission which shifted gears for you. As such it was jerky and not very good. This uses dual clutches much like the VW DSG. By using two clutches the shift time is reduced and the smoothness is greatly increased. Drive a DSG GTI and then go drive an e46 (old) SMG M3 and you'll immediately notice the difference. Neither are automatics with torque converters but have automatic modes which shift gears when RPM/throttle position reaches a preset level.
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Playdrv4me 4:23PM (1/17/2008)
I'm a huge BMW fan but this over wizardization of essential driving functions is one of the real problems with their most recent cars, with the M5 in particular.
After alot of pressure BMW finally agreed to bring over a good ol' grassroots 6 Speed stick version of the M5, but only in limited numbers, and with no promise that it would continue. Now I hope they aren't planning to ax the manual M3 over this complex gearbox, no matter how good it is.
The beauty of a manual transmission has as much to do with the overall feel it provides as how quick it is or isn't.
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M3_in_MTL 4:57PM (1/17/2008)
I own a E46 M3 SMGII and it is not by any means a slush box. Nor is it the smoothest either, this gear box was initially bread for track duty (hence the only gear box available on the CSL).
The shifts are executed so fast and hard when the firmest setting is activated that the front end doesnt drop during each shift under hard acceleration, absolutely amazing... and for the "feel" i dont miss my clutch on bit, at the track or on the street!
As for the new twin clutch gear box, im positive the revision was soly focused to make the gear change less "intense" and more seamless for your mid-life crisis posers (BMW's target group).
zach 5:19PM (1/17/2008)
"M3 in MTL" -
Your comments imply that you think the ability to shift smoothly is a desirable trait only for yuppies, not for enthusiasts. Maybe this is what you meant, maybe not... but you're mistaken if you think that twin-clutch transmissions don't make hard shifts when appropriate.
The real purpose of twin clutch transmissions is to shift more quickly AND more smoothly; resulting in less interruption of power to the wheels. I have no idea how you twist this around and make this a "poser" transmission compared to yours. That just doesn't make sense.
M 11:29PM (1/17/2008)
Well said Zach
James Russell 5:08PM (1/17/2008)
Oh thank god. Regardless of their merits, auto-manuals with a stick go up through the gears by pulling back, and down by pushing forward. Why is the industry increasingly dyslexic on this basic point?
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zamafir 5:33PM (1/17/2008)
I think the same reason BMW's cluster is switched, it makes them different.