what's the difference between SMG and DCT?

[jc@]

im currently using SMG I with my 325. it's really satisfying and challenging. quite hard to get used to it at first ( to drive it on low speed smoothly)tried to search for E90 with smg but seems that it's no longer in action since the M3 is also using DCT.so how exactly doest this DCT work?one thing to know is it surely heel-and-toe itself while shifting down right?i think heel-and-toe also applies in my tranny, but it's not as smooth as do it manually using a stick.so anyone using DCT here? care to share your experience?thank youregards,JC

 

[B33mEr]

DCT if i'm not mistaken is a Dual Clutch Transmission system similar to VW DSG. Fyi ... SMG (SSG), SMG1,SMG2 and SMG3 is an AMT system whereby it's a normal gearbox only w/o a clutch pedal. DCT is a new offering from BMW where it was offered 1st on the M3 convertible shortly after it was also available on the E90 M3 sedan ... when one select an odd gear number e.g 1,3,5 the DCT g/box already have the next even numbered gear e.g. 2, 4, 6 engaged ready and waiting for the driver to engage the next shift hence the gearchange is very fast and smooth, it's like having 2 g/box in 1 hence the term dual clutch transmission (DCT), unlike the SMG systems which has only 1 clutch for all the gears.

Having said that DCT system adds the overall weight of the car and it's much more complicated than SMG system

 

[jc@]

wow... thanks for the explaination.

:love: let's get one next year

 

[paultantk]

the DCT is now available on the following cars: E90 m3 sedan, E92 M3 coupe, E93 M3 convertible, E92 335i Coupe and finally E93 335i convertible.

 

[zedcat]

Porsche has now also introduced it's version called PDK, Porsche Doppel Keplung (not sure of spelling). They developed it originally for the 956 race car and claimed it was too difficult/costly to adapt for road cars. If not for BMW, Audi and even VW using them I bet Porsche would stay with Tiptronic. I drove a 997 facelift with PDk and it is very impressive. It does vibrate/shudder a little in stop and go traffic. It has wet clutches which are not as smooth as a torque converter at low speeds. Even though the dual clutch tranny is great I would still rather drive a 6 speed- but that's just me.