BMW SMG transmission

[Kabob]

Question, is the BMW smg transmission an actual sequential manual transmission or is it like a Porsche tiptronic transmission? Didn't really see anything doing a quick search.

 

[Arkaign]

It's a sequential manual, essentially a manual where the shift action is computer-controlled, as opposed to conventional automatics with the torque converter, etc.

 

[DivideBYZero]

The e46 SMGII uses exactly the same getrag transmission as the six speed manual, except changes are automated and hydraulically actuated.

 

[Kabob]

Clutchless??

 

[thomsbrain]

Originally posted by: kabob983
Clutchless??

It has a clutch, but it is automated, so there is no clutch pedal for the driver to press.

 

[Kabob]

So it's not a "true" sequential manual?

 

[Arkaign]

Originally posted by: kabob983
So it's not a "true" sequential manual?

Not in the strictest sense, but there is no real delay issues with BMW's version. Shifts in the M5 for example happen far faster than a human could achieve. I prefer a good old manual regardless.

Details :

http://en.wikipedia.org/wiki/Sequential_manual_gearbox

 

[Zenmervolt]

Originally posted by: kabob983
So it's not a "true" sequential manual?

The SMG is a manual gearbox (standard) with gear changes and clutch actuated by electro-hydraulic controllers. It is a true "manual" gearbox in the sense that it is not a torque-converter type. But you are right that it's not a "true" sequential in the way that, say, a motorcycle's gearbox is. That is, you don't run through a pattern of 1-N-2-3-4-5-6. However, the way the control software is calibrated, the driver can only access gears sequentially.

ZV

 

[Kabob]

Hrm, wonder how it compares to a traditional manual in, say, track driving.

Also, what's the difference between the SMG and their new semi-auto that's in the E92?

 

[fstime]

Originally posted by: kabob983
Hrm, wonder how it compares to a traditional manual in, say, track driving.

Also, what's the difference between the SMG and their new semi-auto that's in the E92?

Its might be preferred in a track setting, but on the street a std. 6 speed may be better as they are known not to be user friendly in the sense of jerky shifts in the fastest settings.

The new gearbox is a DSG transmission which uses 2 clutches(still no clutch pedal), it allows for much smoother shifts without the added effect. Supposedly it turned out pretty good in a review I read, they only said it would probably need a few more software updates for the automated mode but it was good mechanically.