Inquiry About SMG Cars

[Cronenberged]

For anyone who owns or has extensive experience with SMG cars, would you be willing to share some insight into them? My only experience with our M3s is a manual. I'm curious about what important questions to ask, whether there are any preventative mileage milestones for the SMG, and what is generally a reasonable price? Any input is greatly appreciated and invaluable in helping me make an informed decision.

[oceansize]

SMG is great but you have to understand cost and manage expectations. It isn't perfect, watch the many CSL videos on SMG. The tech is old.

If you don't DIY then convert to 6MT and be done. The SMG system in good health is reliable but determining good health is tricky. The easiest way to test is pump prime time. Sub eight seconds is good. The second way, and more important to note, is to watch decay in INPA. Watch the pressure decay until the next pressurize cycle while simply idling. The longer it takes the better health your SMG system. An SMG system in great health can take as long as five or six minutes before needing to re-pressurize.

Shops aren't good with SMG, period. They don't want to take the time to diagnose. They want to throw parts at it. Repairs will run into the many thousands very easily.

An SMG car will cost 15% to 25% less than a 6mt.

FYI: To access the pump unit you have to remove the intake. To access the actuator or compression springs shops would drop the transmission.

[Sharocks]

It can be swapped out.

The end.

[maw1124]

SMG is great but you have to understand cost and manage expectations. It isn't perfect, watch the many CSL videos on SMG. The tech is old... The SMG system in good health is reliable but determining good health is tricky.

Following up on this, if you get one that's already healthy, it seems to me that swapping the fluid every 2 years like brake fluid or coolant will keep it that way for longer than most will think. And you can always buy low mile parts from the people swapping them out for 6MT. How long depends upon how and where you want to use it. A fun extra car at an extra vacation home, don't worry so much about it. A daily driver in rush hour traffic in Scottsdale, AZ, be ready to fund that swap at any time. But by now there are enough spare parts and rebuilders around that you're really only swapping if you wanted a manual all along (or because you're sitting in 100* rush hour traffic every day somewhere).

My perspective comes from owning this car for over 12 years and another Pentosin reliant MB AMG for over 14 years. In both cases the manufacturer specified not to change the Pentosin (ever) and in both cases they were spectacularly wrong about that, rendering some very expensive systems near useless and leaving the cars with "black eyes" in the marketplace. Sound familiar? And in both cases, changing the Pentosin every 3/30k miles has eliminated the problem. Not forestalled it. Eliminated it.

YMMV, my cars are not daily use. Surely if you're buying one of these you can afford frequent fluid changes. It's not liquid gold. It's garden variety hydraulic fluid.


maw

[TexaZ3]

SMG is a fantastic gearbox, IF you don't expect it to be a manual transmission. Its quicker, easier on the clutch, and lots of fun when you drive fast.
Owned 5 E46 M3s, 4 of them SMG - last 3 I bought were SMG by choice. Put 225 Euro SMG software on it, and its glorious.

[9kracing]

There's pluses and minuses to both.

I did enjoy the SMG, when it worked. It's a fun transmission. It was definitely finicky though.

There was a couple times the car didn't want to start, and under heavy throttle it shifted fine, but part throttle through the hills was a mess. I missed the control of a third pedal.

Ultimately I swapped mine out for the 6MT and have no regrets, but the older I get, the more I appreciate the SMG for what it was.

[Arith2]

SMG is ok but a CSL conversion is what makes it awesome. It shifts faster than any human could ever dream of but it's also got a raw aggression to it that is lost on automatic transmissions. I'd buy an SMG again because parts are cheap now if they're used. My first M3 was a manual and it was sloppy. I enjoyed driving the car but compared to almost any other sports car, the shifting is garbage. Still, simplicity equals reliability and the SMG is complicated. That being said, it is still super reliable. CHF 11S just has a 5 year shelf life so that needs to be flushed, at the most, every 5 years.

[Cronenberged]

I appreciate everyone's input. I've always wanted a Steel Grey car, and there's one for sale with less than 100k miles at a reasonable price. However, it has an SMG transmission. I've also considered the possibility of swapping it out down the line, but I want to ensure that I understand the quirks, can assess its health, and know how to maintain it properly.

[maw1124]

At these prices... https://bringatrailer.com/listing/20...-m3-coupe-229/

maw

[Chas3n]

Reading these comments it's still, 20 years later, comical to see how misunderstood SMG is. If I could I'd trade my 6mt for another SMG!

If you DO drive SMG like a manual, it's great. Lift off throttle during shifts, rev match down shifts ect. It's when you drive it like an automatic that it becomes a clunky mess.

[oceansize]

Reading these comments it's still, 20 years later, comical to see how misunderstood SMG is. If I could I'd trade my 6mt for another SMG!

If you DO drive SMG like a manual, it's great. Lift off throttle during shifts, rev match down shifts ect. It's when you drive it like an automatic that it becomes a clunky mess.

Almost everyone in the thread said they liked their SMG. What am I missing? Where is the comical part? Personally my car never leaves manual mode.

[maw1124]

It's when you drive it like an automatic that it becomes a clunky mess.

Who does this?!?! And why?!?! Like, why would you ever??

maw

[Vonbimmer]

Afternoon All! Just wanted to weigh in with my experience on this front. We picked up an 03’ M3 convertible smg last May for my wife and to keep my 01’ 6spd coupe company lol. The smg was better at paddle daily driving than I expected and at full rip works great.

That said about a month in the pump was running too much and would not make enough pressure so I swapped it with a reman assembly from mlreng.com and did the bleed and adaptions all was well and the car was doing great. Now fast fwd about a year and we have new smg errors ,sporadically won’t go into gear and then the next day is fine for a while. Of course the first time it stranded the car in the street in front my my house temporarily. The error is 16 solenoid valve gear forward and it sounds like it could be a solenoid on the pump assembly or wiring. So I guess the moral of my story is smg is fine for diy owners that don’t have to have the car cooperate as a daily.

[JayVee]

10+ year owner of a 2004 SMG II car. Currently just south of 140,000 miles. Here is my take:

SMG is amazing. The access to this level of technology in 2004 short of the Ferrari F1 transmission or Lamborghini E-gear was unheard of for this time period. To me, it's special. Manual is fun, engaging and amazing to drive. But my personal take is that you can buy most fun sports cars with a manual, but you can't buy them with an SMG-II single clutch transmission. At high RPMs where the S54 loves to run free, the matchup is second to none. And no, a manual car cannot outshift an SMG, it's too fast.

I do believe a proper CSL tune is necessary. My car started to stumble in first gear at around 130,000 miles. I suspected the clutch was worn and it turns out it was the linear actuator tip that was worn. I ended up having this replaced, a new clutch installed along with upgraded and refreshed parts in the transmission. That was about a $4,000 job. I easily could have swapped the car for that, but chose not to. This is also when the CSL tune was installed which was a huge upgrade due to the increase in shift smoothness and speed. I don't track, beat, or drive my car hard but I do enjoy what the mechanical combination has to offer.

Now.. Single clutch transmissions were the precursor to dual-clutches. A DCT will do everything the SMG can, but more refined, and this is why they were only offered for a short time period. The only thing you don't get is the raw feeling and gear shifting that the single clutch offers, and in my opinion is more fun and more special to drive.

[nyc951]

I have an e39 528i that has sentimental value. I’d love to swap a S54 and SMG into it. I think it’d be a great combination, with automatic mode for those lazy times.