Random tidbit of curiosity

"PetarVN, GLI Guy, now with stupid power" (petarvn)
11/12/2014 at 16:06 • Filed to: None

How does the BMW SMG transmission work? I get it's a dual clutch auto, but does it require ATF, or some special DSG-like fluid? also, I'm assuming it's a dual-clutch, right? also, does it automatically up/downshift in some cases?

DISCUSSION (60)

Sweet Trav > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 16:06

They work badly.

Brian Silvestro > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 16:07

Not a dual clutch. They are bad. Whatever Rusto says, don't listen to him.

Textured Soy Protein > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 16:08

The BMW DCT is a dual clutch transmission. I have one in my 135is and I love it.

The SMG is a single clutch automated manual transmission. They're...not as good.

Party-vi > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 16:09

SMG is not a dual-clutch auto, but a fully manual transmission that used an automated clutch.

Jonathan Harper > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 16:09

SMG is not dual clutch. It's basically a manual transmission with an automatically controlled clutch. They are not ideal, but once you get the hang of it there's no real issue so long as you blip at the right times and employ a featherlight foot for small inputs.

Source: I've driven many SMG BMWs.

PetarVN, GLI Guy, now with stupid power > Party-vi
11/12/2014 at 16:10

ok, that makes sense! :)

FromCanadaWithLove > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 16:10

How does the BMW SMG transmission work?

Trick question. It doesn't.

(Hyperbole, but think of it as a regular manual without the clutch pedal or cool factor.)

RallyWrench > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 16:13

Others are right, it's an automated clutch and gear selection. It's mechanically the same gearbox as the manual car, with the actuator package bolted on. DCT is completely different, and is a dedicated dual -clutch box.

Cé hé sin > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 16:13

It's like a Smart with (in the M5) more gears.

RazoE > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 16:14

I think I read on Oppo you can convert an SMG to use a clutch pedal and shifter, so it's an automatic CLUTCH on a manual with paddles instead of a gated shifter.

RPM esq. > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 16:15

Others have answered your first question (single-clutch manual with an automated, hydraulic-actuated clutch), but to answer your second: it has two settings, one where you shift yourself and one where it shifts for you, which it will do like a not-very-good automatic. (It also has settings for how aggressive the shift points are, which is nice). I know I'm in the relative minority in saying that I enjoy driving the SMG II, but only when I shift it myself—although the auto feature can be convenient in parking garages and the like. However, it is relatively idiot-proof: when you are manually shifting, it will automatically downshift for you when you come to a stoplight if you forget.

ly2v8-Brian > Brian Silvestro
11/12/2014 at 16:16

I haven't driven one so... How bad is it other Brian?

Brian Silvestro > ly2v8-Brian
11/12/2014 at 16:18

I've heard it's pretty bad, other Brian. I've never driven it either.

PetarVN, GLI Guy, now with stupid power > RPM esq.
11/12/2014 at 16:19

ok, good to know! :D

and thanks for the "owner's perspective"!

ly2v8-Brian > Brian Silvestro
11/12/2014 at 16:20

hm, track one down at a dealer and test drive it maybe.

Brian Silvestro > ly2v8-Brian
11/12/2014 at 16:21

how about lazy

KusabiSensei - Captain of the Toronto Maple Leafs > Jonathan Harper
11/12/2014 at 16:21

At least it's not the Saab Sensonic gearbox.

http://jalopnik.com/for-10-000-com…

Manuél Ferrari > Brian Silvestro
11/12/2014 at 16:31

SMG rules!

ly2v8-Brian > Brian Silvestro
11/12/2014 at 16:46

the struggle is real

Too many M's > Manuél Ferrari
11/12/2014 at 17:07

They rule low resale value ;)

Too many M's > RazoE
11/12/2014 at 17:11

Ehhh, no. You can convert to a regular three pedal clutch system. Since all BMW did was put the hydraulic actuator on a regular manual box and delete the pedal. When the hydraulic actuator fails, you can remove all this and add the third pedal. There is no automation after this conversion.

Too many M's > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 17:17

To come to the aid slightly of the SMG, for a DD where the purpose is to use it as an automatic this is a less than nice tranny to have. In the most aggressive setting on a track, them this can be very beneficial. I know a few Nurburgring 24 hour and VLN teams that prefer this since you can prevent the probability of a bad money shift. Definitely handy when you've been up for 36 hours in the middle of the night.

Me personally? I don't dig it for my use, but for a competitive multi-driver team then it makes sense.

Manuél Ferrari > Too many M's
11/12/2014 at 17:20

true!

RazoE > Too many M's
11/12/2014 at 17:27

no, I know. I meant it's a "regular" manual with the clutch automated.

Too many M's > RazoE
11/12/2014 at 17:29

Gotcha, the comma placement made me think you were still talking about the SMG conversion.

RazoE > Too many M's
11/12/2014 at 17:31

yea, re-read it and i made it sound like you could have 3 pedals with an automated clutch. Which wouldn't make sense..

Manuél Ferrari > Brian Silvestro
11/12/2014 at 18:40

"Everyone on the Internet says it's bad so I'll believe them"

Manuél Ferrari > ly2v8-Brian
11/12/2014 at 18:40

Don't listen to other Brian

Manuél Ferrari > Jonathan Harper
11/12/2014 at 18:42

Manuél Ferrari > RPM esq.
11/12/2014 at 18:44

Yeah I only use auto mode if I'm holding a coffee or something

Manuél Ferrari > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 18:47

So I read all the comments and one thing is missing. The only objective issue with SMG is maintenance/repair costs. Whether or not people enjoy driving it is a subjective taste. I for one really like SMG. But one thing I can't argue is that Manuél is more reliable and cheaper to own. That is why Manuél is our one true lord and savior. He's even better than a DCT.

Brian Silvestro > Manuél Ferrari
11/12/2014 at 18:47

basically exactly. You're outnumbered.

Manuél Ferrari > Brian Silvestro
11/12/2014 at 18:48

LOL

See the comment I just sent to the OP. I think you will approve.

Brian Silvestro > Manuél Ferrari
11/12/2014 at 18:51

PRAISE MANUÉL

Manuél Ferrari > Brian Silvestro
11/12/2014 at 18:53

HE IS OUR TRUE LEADER

I just read the FP post on the AMG GT

I swear to Manuél that if the GT came with Manuél I would trade the bimmers and the 997 for it.

Brian Silvestro > Manuél Ferrari
11/12/2014 at 19:05

I just lol'd hard

I would sell body parts for it. It's so damn sexy, and LIGHT

PetarVN, GLI Guy, now with stupid power > Manuél Ferrari
11/12/2014 at 19:10

hmm... is the SMG really that expensive to maintain? Give me an example on price for maintenance, I wanna compare it the the DSG, as it's the automated gearbox I know most about.

ly2v8-Brian > Manuél Ferrari
11/12/2014 at 19:17

I'm going to keep an open mind

Manuél Ferrari > ly2v8-Brian
11/12/2014 at 19:36

You can drive mine and see for yourself

ly2v8-Brian > Manuél Ferrari
11/12/2014 at 19:42

are you in MN then?

Manuél Ferrari > PetarVN, GLI Guy, now with stupid power
11/12/2014 at 20:03

Yeah :/

I haven't had any issues

But I heard the SMG pump can die and cost like $6K to fix

DSG is a DCT, which has a totally different design. The single clutch automated manuals are kind of a hack. DCTs were designed from the get-go to be paddle shift

Manuél Ferrari > ly2v8-Brian
11/12/2014 at 20:05

no. you'll have to take a vacation to So Cal :)

Manuél Ferrari > Brian Silvestro
11/12/2014 at 20:08

It is light for something with dat much luxury!

Imagine the future AMG GT Black

It might be so good that it will be worth buying even without our lord and savior chilling inside

ly2v8-Brian > Manuél Ferrari
11/12/2014 at 20:09

Busy with school.

Brian Silvestro > Manuél Ferrari
11/12/2014 at 20:15

But the wing they're gonna put on it will ruin everything

Manuél Ferrari > ly2v8-Brian
11/12/2014 at 20:16

Makes sense. Gotta finish dat school and get a good job