Jycke

http://www.worldcarfans.com/11107113...ions-announced

I'm not a tech but as far as i've understood, the DCT is faster than the MCT?

TexasEngineer

The DCT In the B class cannot handle the torque of the M156 engine and is also in no way compatible with the C63 layout.

A better question to ask would be, why the AMGs don't get the dual clutch transmission from the SLS?

hhughes1

^$$$$$$$$$$$$$$$$$$$$$$$$$$$$^ Price justification for the SLS

mthis

The trans in the SLS is mounted in the rear and in the C's is up front so to change all that would be mouchhhhhhh pesos so they use the same trans and change it up a bit and call it MCT.

Jycke

Alright, thanks for the answers My mind is at ease

TexasEngineer

It is true that changing to the MCT transmission was an easy transition mechanically. Not only that, but the MCT is already in use in Many AMGs. The MCT is certainly a cheaper option than DCT.

As for the SLS transmission being remounted, it does not take that much engineering effort to front mount it. A different bell housing and output would be the vast majority of what is needed. For example, the rear mounted Corvette transmissions, both the auto and manual, are the same transmissions as found in the CTS-V and Camaro.

TexasEngineer

After taking a closer look at the SLS transmission, it is much more integrated into the differential than I had previously thought. It would need a lot of redesign work for front mount applications.

2010_C63_OMG

The better question is how much does a DCT cost to make vs the 7+2 speed tranny (old or MCT). I can't image it costs that much more, since even the 328i can have this option.
I test drove the M3 with DCT, and while the shifts are quick and smooth, it reminded me of my lexus GS. almost too serene. i think the C63 jerk/jolt with gear changes feels more visceral.

Jycke

7+2?

SMP

The MCT is just an automatic transmission using a wet start up clutch instead of a torque converter. Not costly at all to produce.

The DCT is far more complex than the MCT and therefor is more expensive to produce. It uses two subdrives connected to the engine with two clutches. One subdrive for the even gears, one for the odd gears. This is the reason why it shifts seamless. It also doesn't loose any forward momentum between shifts, which makes cars like the GT-R or the 997TT (besides the AWD from a dig) put the power down so efficiently.

I don't know what you're talking about, but I don't feel much of a jolt in my CLK with the 7G transmission. Compared to the SMG in my M6, it feels like a rubber band. In the most aggressive setting shifting at 8200 rpm, it feels like the rear end is coming apart. That's not just in the first 2 gears, but all the way up to 4th gear. Part of the reason most people didn't like that transmission.

bmoney12

Did you have the M3 in the most aggressive setting? I had an 08 M3 with M-DCT for a couple of years and in most aggressive setting (S6 I think it was) it would give you a pretty good jolt. Definitely more of a jolt than my C63.

Mort

7 forward gears and 2 reverse gears. 2nd reverse gear has a higher transmission ratio to make pulling away on ice and snow easier and safer.

Jycke

Oh, thanks I had a couple of guys riding with me in may and they were jealous that my (our) car reversed quicker than theirs accelerated :P

2010_C63_OMG

2 reverse gears: I think the C mode vs S mode switches between the two gears?

M-DCT: my bad. when I test drove it, it was probably on the least aggressive settings. I'll have to try it with the S6 setting next time.

there's no question that DCT is better than the 7G. But the BMW DCT is only $2900, and AMG already did the R&D on the SLS DCT. so why can't they give (nonSLS) AMG owners that DCT option? i can't imagine that this DCT would cost much more than the 7G, and most AMG buyers would probably pay the extra $.

SMP

I agree. Should be offered at least as an option....... Next time you take an M3 out, turn off TC first, otherwise you can't select S6.

rage2

The SLS DCT is a getrag unit. Mercedes doesn't have their own dual clutch transmission yet, so you'll only see that transmission is low volume cars like the SLS until they have one. The speedshift mct is a stop gap solution until they're ready with their own in house dual clutch gearbox.

hakaida442

It would be nice if the AMG cars would get DCT. If porsche can have it available for every car in their lineup I don't see why Mercedes can't do the same for it's sportiest cars. Even the mitsubishi evo has dct.

rage2

Like I said in my previous post, it'll happen when MB develops an in-house DCT. The other manufacturers are able to get DCT's across their lineup faster than Mercedes by outsourcing transmissions. Porsche's PDK comes from ZF, Mitsubishi and BMW's come from Getrag, while Nissan and VW comes from Borg Warner.

jvanbrecht

I don't see why MB would do it inhouse when everyone else outsources. Look at the AMG exhaust system, that is outsourced without any issues.

Why reinvent the wheel, when there are perfect solutions already out there. I suspect MB based their choice on cost.

2010_C63_OMG

AMG outsources a lot of things, like Bilstein shocks, EDO dials, Momo steering wheel, Bordet rims. why not a tranny custom build for the 63's? (same engine!).

But yeah, I think AMG owners would gladly pay $3000 for an outsourced DCT. maybe part of the next performance package with LSD. I think the AMG seating package was $2900?