peetah

On the BMW 545i 6-speed, it has this thing described as:

"This enables short, rapid gear changes through all six gears via the steering wheel paddles or selector lever, without the use of a clutch. (Requires Sport Package.)"

How does this work? Does the driver still need to back off the accelerator when changing gears? It sounds like the paddles replace both the shifter and clutch.

Buff-Daddy

It's a lot like what they use in the Formula 1 cars.

tycoon

But that still can't beat manual transmission...

gilboman

for launch no..for downshifts...definitely yes..by a long shot. for upshifts yes its faster than a manual.

Lung Fu Mo Shi

One of my wishes. I love SMGs.

Watch the WRC. Clutch is used only for launches (or limp-mode) and the rest of the run is flipping the paddles back and forth.

biker

The BMW SMG on the 5 series has many modes including a mode where it acts like an automatic (when you have to lend it to your wife). It has special modes to improve launches too. The shift time is measured in milliseconds! This SMG is different/newer than the one in the M3. Like most other things BMW you will only notice its advantages at the extremes, otherwise it's just a WOW/$1K option.

gilboman

umm...you would notice it everytime you have to shift unless you leave it in auto mode, being able to downshift two gears in a row with perfect rev match and all faster than a manual driver can ever dream of.

biker

I said you will might notice its "advantages" at extremes not daily difference. If you look at the 0-60 times for a manual and SMG there's very little difference. Like a regular manual after a week shifting gears will become fairly routine and most owners won't give it a second thought. Actually after the WOW wears off I'd venture to guess that most folks will just leave the thing in auto mode and shift it themselves only once in a while. And after enough problems surface with the system the number of people excited about the feature will trickle to a halt. SMG on the new 5 series not even available until the spring.

DEVO

depends which version of SMG... the SMG version on the Z4 bites the big one... it takes several seconds for first to engage... same goes with reverse... and it doesn't beat the manual.

a complete joke.

biker

DEVO, have you heard about the software upgrade that supposedly fixes this problem? Like I mentioned in another thread, so many things will be software controlled that some coding geek will control the drivability of future cars and soon we'll be talking about car software versions instead of model versions.

DEVO

I haven't heard of the "fix" but the nice thing about the Z4 version is that there are about 3 modes... which is good... I think the M3 version has something like 11 modes. You might as well provide an interface so that you can program the mode via a laptop.

gilboman

notice how others have said the SMG is not good as a manual for launch, and if the people were not enthuasists, they would've just stuck with the regular 6spd auto and not the SMG. if you get the SMG, you would most likely be an enthuasist.

Buff-Daddy

It might be a WOW option to some and "exactly what some people were looking for" to others. Just like with Step-Tronic Auto's, it is there if you want to play, but you don't have to use it. SMG is just a more advanced form or Steptronic and gives you a few more options to play with "if you want to". Otherwise, in bumper to bumper traffic, you can just slip it into auto and relax...
The point is that they are not forcing it on anyone. It isn't like they are taking away the standard manual and only leaving people with this option. And that is what people either love or hate about BMW's, OPTIONS!

DEVO

I wouldn't call SMG a more advanced Steptronic... your relationship with Steptronic implies sequential gearbox when one doesn't exit... if anything Steptronic is a more advanced automatic transmission.

A sequential transmission is an entirely different beast... just like you wouldn't call a CVT transmission an automatic tranny.

Dan Martin

The SMG tranny feels like it is more directly connected to the transmission than an AT because it doesn't use an automatic torque lockup converter. Functionally it's very similar to a MT.

If any one is interested, Getrag makes the SMG for BMW. We were going to make some parts for it so I've seen many of the prints. Here's a link: http://www.en.getrag.de/183/183

Buff-Daddy

I didn't know we were speaking in technical terms. By more advanced, I meant that it gives you a few more options/modes. The key point is that you don't have to buy it, it is an option so there is nothing to worry about...

peetah

So there is a clutch? Or is the clutch used only on race cars? There's not much info on this on BMW's website.

schalliol

Perhaps check out this thread

manual tranny... a dying art????

Buff-Daddy

No clutch.

schalliol

Well, there is, but it's not human actuated.

biker

Hydraulically actuated and computer controlled solenoids take place of the clutch pedal and linkage. The rest of the tranny (including a regular clutch) is a basic manual tranny. The solenoid takes place of your foot and the computer takes place of some of your brain/foot function in accomplishing the shifting. You provide input via shift padles on the steering wheel and the computer takes over from there. Of course in the auto mode the computer does everything for you.

Buff-Daddy

Like I was saying, no clutch... 2 pedals, gas and brake...