Choy

New member and recently bought the 2012 C300 4matic. I currently drive an 08 M3 E92 with DCT tramsmission. I am seriously thinking of getting the 2012 C63 Coupe with standard MCT trans. I read from another thread regarding response problem when changing shift mode from C to S+ while driving/accelearating. If I'm not mistaken, the MCT is new for 2012 C63 but has been around for other AMG Benz.

The M3 DCT had a lot of early problems but were resolved as years past by. So my question is, is MCT similar to DCT? In my DCT, I can change the shift mode from S1 to S5 in a fly. Also from D1 to D5. Going to S6 is different as the car must be stop and the stability control totally off before you can change to S6. Also, I can change from S (manual) to D (auto) in a fly.

Any first hand experience here with some pros and cons of MCT. I already built my 63 and on the fence as my SA is waiting for my sig. Thanks in advance.

Yuille36

A dual clutch transmission eliminates the torque converter as used in conventional automatic transmissions. Instead, dual clutch transmissions that are currently on the market primarily use two oil-bathed wet multi-plate clutches, similar to the clutches used in most motorcycles, though dry clutch versions are also available. In DCTs where the two clutches are arranged concentrically, the larger outer clutch drives the odd numbered gears, whilst the smaller inner clutch drives the even numbered gears. Shifts can be accomplished without interrupting torque distribution to the driven roadwheels, by applying the engine's torque to one clutch at the same time as it is being disconnected from the other clutch. Since alternate gear ratios can pre-select an odd gear on one gear shaft whilst the vehicle is being driven in an even gear, (and vice versa), DCTs are able to shift more quickly than other cars equipped with single-clutch automated-manual transmissions (AMTs), a.k.a. single-clutch semi-automatics. Also, with a DCT, shifts can be made more smoothly than with a conventional Automatic Transmission, making a DCT more suitable for conventional road cars.
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Mercedes-AMG developed the 7-speed MCT "Multi Clutch Technology" planetary semi-automatic transmission.
The MCT transmission is essentially the 7G-Tronic automatic transmission without a torque converter. Instead of a torque converter, it uses a compact wet startup clutch to launch the car from a stop, and also supports computer-controlled double declutching. The MCT (Multi-Clutch Technology) acronym refers to a planetary (automatic) transmission’s multiple clutches and bands for each gear. The MCT is fitted with four drive modes: “C” (Comfort), “S” (Sport), “S+” (Sport plus) and “M” (Manual) and boasts 100 millisecond shifts in "M" mode. MCT-equipped cars are also fitted with the new AMG DRIVE UNIT with innovative Race Start function. The AMG DRIVE UNIT is the central control unit for the AMG SPEEDSHIFT MCT 7-speed sports transmission and all driving dynamics functions. The driver can change gears either using the selector lever, or by nudging the steering-wheel shift paddles. The new Race start Function is a launch control system which enables the driver to call on maximum acceleration, while ensuring optimum traction of the driven wheels.

I hope that this gifts some valuable knowledge between the two.

93 Octane ABC

A true double clutch transmission will always be better than a Mercedes AMG MCT anyday. No comparison on the track, straights, and everyday driving.

AdrianL

I recently sold my C63 in favour of a 6speed M3. The C63's auto trans is civilized and works well on the track, but it feels (in track environments) like it's a little lost.

SMP

The 2 transmissions are completely different in construction. The MCT is the standard 7 speed automatic, used in 2009-2011 C 63's, but instead of a torque converter has a wet start up clutch. It's a little more responsive and quicker, but will never match a dual clutch transmission. It's also bigger and therefor much heavier.

A DCT is an automated manual transmission. Compared to single clutch transmissions like the old SMG, it has 2 sub drives. One for odd gears, one for even gears coupled to the engine with 2 clutches. Gear changes occur much faster, because the next gear is just a matter of opening/closing one of the clutches. It's much more efficient compared to an auto box, faster shifting, more responsive, lighter and depending on the manufacturer, has a lower center of gravity.

Yuille36

SMP, I agree with your assessment, the DCT is better overall. That is why it was incorporated in the SLS AMG.

Choy

Thanks for all of those informative responses. From what I read, it looks like M3 DCT is better than the 2012 MCT. In addition, my assumption is that the 2012 MCT trans is better than the earlier C63 AMG model (2011 and earlier).

KEMA

DCT might be slightly better than MCT but the C63 Coupe is far superior to the M3.

Your choice

Ken

lebreeze

Not sure if I would say far superior

Vic55

The facts posted about the two trannys are spot on... I have had three DCT style cars and that included an E92 M3 (GTR and 997TT PDK). I currently have the MCT in my E63 and the differences are noticeable:

Transmission shifting up and down in manual and auto modes are faster in the DCT.
Paddle shift responses in shifting up and down are faster in the DCT.

I also believe based on dynos that I have seen here and in other forums that the DCT is a more efficient tranny; ie less DT loss to the ground which clearly shows in the GTR and how a 414 hp M3 can make up most of the ground lost to some higher hp cars.

Choy

I don't know if it is far superior. I like the new interior of the C63 than the M3. I am torn between the two engines. The high reving M3 or the high power/torque C AMG. For everyday car, I think the C AMG has the edge but for track I prefer the M3. That is why I am still on the fench. I love both cars and it is a toss-up.

I am waiting for my dealer's 2012 C Coupe AMG for test drive. Maybe by then, it will swing me to get the C AMG.

SMP

That's what I like about uncle Vic ...... always speaks of first hand experience.

Vic55

I forgot to add that the DCT in the GTR and E92 M3 also seems or feels to paddle shift faster up and down the gears than my PDK 997TT... The MCT is a distant 3rd but still faster than a traditional slush box that I had in my CL65 and W211 E55 in both paddle shifting and transmission shifting.

SMP

Your car has SC, right? If you put it in Sport+, it's pretty quick. However, like all Porsche turbos, you have that slight delay because of lag. What really annoys me is starting from a light and the hesitation between throttle input and actually taking off. I'm pretty sure it's software related.

SonnyakaPig

This is something that just came to mind for me: We typically apply a 18% drivetrain loss to the 7g-tronic (722.9) trans. And to manual transmissions like the Tremec TR-6060, we apply a 15% loss (I'm guessing the M3's manual's drivetrain loss fits that appoximation).

I was reading on another site yesterday that the BMW's DCT is believed to have 2% more drivetrain loss than the M3's manual. So, if that is true, and the manual loses 15%, then to the DCT we would apply 17% drivetrain loss. But, if that's true, then doesn't it seem unlikely that the DCT is only 1% more efficent than the MB 722.9 auto trans, which is believed to lose 18%?

The differentials for the drivetrain losses of the above three transmissions would make more sense if the M3's manual transmission actually contributed less drivetrain loss than 15%. But, if that's true, what makes the M3's manual more efficient -- with respect to drivetrain loss -- than the Tremec TR-6060 6-speed manual used in the Corvette Z06?

Of couse, another possibility is that the 722.9 auto trans loses more than the believed 18%.

I'm just trying to make sense of these numbers.

SMP

Drivetrain loss is obviously higher in a DCT compared to a 6MT. It has to spin one additional gear since it's a 7 speed, but most importantly, it has to spin the second sub drive.

What makes a DCT more efficient than a 6MT? There is no torque interruption between gear changes to the wheels.

gthal

This is a great topic. My current car is an M3 with the DCT transmission and it is truly an amazing transmission... instant everything... and I mean instant.

As I work through the details on a new 2012 C63 coupe, I worry that I will be disappointed with the MCT tranny. I'm sure it will be very good but the DCT in the M3 is near perfect, IMO, for aggressive driving on the street and track. I'm really hoping the MCT is at least somewhat comparable.

Choy

I am hoping that the MCT is somewhat comparable to the M3 DCT. I am just waiting for that test drive to do the actual comparison. Driving the M3 DCT since 08 can give me an insight on how close in performance the MCT is. I don't expect the MCT can out perform the DCT but expecting a lot better tranny than a normal auto trans. Maybe closer in performance to the M3 DCT.

Lizard

This is the same reason that I can't bring my self to get a CLK BS as much as I love the car. Maybe I'll have to wait for the C BS and see.

izzyAMG

Did a bit of research MCT = is short for Multi-Clutch Transmission.

I use to own a GTI and an EVO X MR which has a similar variation of this trans. It would be interesting to know the difference between different car manufacturers dual clutches.

I came across this article, looks like a winner.

http://www.emercedesbenz.com/Nov08/1...New_Award.html

rage2

Good old marketing...

Mercedes MCT is simply the 7G Tronic, with the torque converter replaced with a wet startup clutch. It's "multi clutch" from the various clutches inside an automatic transmission, and the startup clutch.

The DSG in the GTI, and the SST in the Evo X MR are dual clutch transmissions. Completely different beasts.

izzyAMG

So as I learn more about the MCT being inferior to Dual clutch designs in theory. But Why? why would Mercedes put it's design effort on a system that would be referred by enthusiast as less than a Dual clutch design?
Also is the MCT More similar to the IS-F transmission design? I heared that it is a great transmission but still a torque converter.

DuaneC63

I think the MBZ target market is not as track oriented as the BMW target market. I see more people in AMG's that only buy them because it's the top of the line. 99% of them would end up in the weeds on a track day. Also MBZ has only one transmission option as opposed to BMW having two. For the less track oriented track market they had to get feel of a full auto with nearly as much as the performance of a DCT, hence the MCT wet pack clutch set up. Given BMW unpleasent experiences with the SMG tranny, MBZ had to get it right the first time as they have no fall back position (ie a full manual) other than reverting to a torque converter. Hence they made some compromises and pursued are more conservative path which is typical of MBZ.

Garmool

Any chance Mercedes do a manual transmission in the near future? or just not gonna happen?

gthal

I think you are right... it's too bad though that they don't offer the true DCT that is in the SLS as an option. I would definitely fork over the extra cash for it.