My #ThursdayRant: The truth about the "dreaded" SMG M3...(and why it's definitely NOT an automatic!)

02 Jul 2015

I get a lot of negative comments and questions about the SMG gearbox in my E46 M3, but mostly from people who know nothing about them. So I decided to settle a few rumours by explaining a little more about it and why I opted to buy it.

The most common question I get is: “How many times has it broken?” usually followed by: “…and isn’t it about £3500 ($4700) to repair it when it does break?” Truth be told, yes I did once get a fault but it was a sensor switch on the side of the gearbox. The car ran in limp mode and it cost me me £18.75 to fix. Other than that, my SMG gearbox has currently survived for over 13 years and 140,000 miles, and has outlived an engine. I have a few friends who also drive SMG M3s, and guess what, theirs aren’t broken either!

The other big question I get from fellow petrolheads is: “So why didn’t you just buy a manual?” Now I don’t actually mind this question, because it enables me to talk about the gearbox’s benefits…
A few years ago I used to run a track day company, which offered advanced driver tuition to people who would bring their own cars to racetracks around the UK. The E46 M3 is a very common car of choice for track day drivers, and I was finding myself behind the wheel of at least two almost every week. I loved the manual, but the SMG felt so captivating with the paddles and fast shifting when on track. To me, it just felt more special than the manual, and that’s what prompted me to buy one.

Here are the Q&As that might help dispel a few scary stories.

Q: So what is SMG? It’s an auto, right?
A: First thing’s first, no, it absolutely, definitely is not automatic. The car does not automatically start moving forward when you take your foot off the brake pedal and the car does not shift up the gears for you if you forget to pull the up-shift paddle either. It really will just bounce off the rev limiter. SMG stands for Sequential Manual Gearbox. It’s actually the same manual gearbox that is found in the cars with a clutch pedal, but instead of having the clutch foot operated, it has the clutch electro-hydaulically operated via a pump and wired to computers. I want to say it’s similar to Lamborghini’s original E-Gear system, but I don’t know enough about Lamborghini’s system to say for sure (please chime in if you know). With the exception of a few software updates (and an extra gear), it’s also pretty much the same Sequential Manual Gearbox offered in the E60 M5 and E63 M6, but yet they don’t seem to get the same hate.

Q: Does it put down the same power?
A: Yes.

Q: Is it as fast?
A: Independent testing actually suggests that in the most aggressive S6 setting, it shifts faster than even the fastest manual driver. However, real world comparisons tends to have SMG and manual cars neck and neck. So yeah, pretty much.

Q: Isn’t it much heavier?
A: No, not really. SMG cars weigh about 8kg/18lbs more.

Q: So why is it so hated?
A: Because when the system does have issues it’s headache inducing and wallet draining. However, problems are always easier to understand when investigated and broken down (as opposed to pointing in the general direction of an SMG and simply saying “all that is one big mess”).
The transmission itself usually holds up fine; it’s the hydraulic pump, the solenoids, and the relays that fail (and if you really want to get technical, the pumps tend to hold up fine, it’s the motors within that fail). These items can get expensive.

Q: But it’s not as involving and engaging as having a clutch pedal, right?
A: That’s all opinion. Would you think the 458 Italia and 991 GT3 are also cars that aren’t involving? I drive both a manual car and an SMG car and I find the SMG car to be fun in very different way.

So there you have it. Hopefully i’ve dispelled a few myths about the contraversial SMG M3. Any further questions? Feel free to fire away!

Q+A’s taken and adapted from here.

Comments

Let’s call it a semi-automatic. That’ll make everyone happy.

The SMG is a boring manual and an uncomfortable automatic. There is no point. just becuase its not a planetary gearbox does not mean its a manual. When you shift gears in an SMG you are just pressing a button that goes into a computer and robots do the shifting. A manual transmission requires the driver tk physically depress the clutch and pull the gear into place.

So pretty much it’s automatic.

Fellow SMG M3 owner here. Great post. Another plus is that the clutches tend to last a lot longer in SMG cars than manual cars (anecdotal). I’ve owned many manual cars and find the SMG to be just as engaging, on a track in S6 it’s a truly special thing. It’s not even that bad around town, it’s a transmission you need to learn. A lot of the criticism of it comes from people who jump into one once and hate it because they find it clunky. If you jumped into a manual car for the first time in your life, you’d probably hate that too lol. Once you learn how to drive it the way it likes, it’s as smooth (or aggressive) as you want it to be. Besides…. paddles are cool.

This is a good post on SMG, there are definitly pros & cons in owning one. I have just had mine in with a BMW technician for the last month when the SMG light came on and things started to go downhill (basically the car would jump out of gear and in to N and leave you stranded until it decided to find 1st again). Thought the worst but after doing some of research it turned out to be sensor realted. Had to replace the gear position sensor which i’m told has it sorted now.
There is a software update that can be flashed to the SMG ECU which i would strongly recommend being done.

My question is, why didn’t they just use a Dual-Clutch???
At least then it would have been better, in pretty much every possible way.

They’re much heavier and the technology wasn’t quite there back in the day.

I loved this article. Really ‘educative’… I hadn’t read anything about the SMG before, and I think that this is a good choice instead of buying an automatic. Driving with that gearbox seems like a lot of fun. However I’m a driver from the old school, so I would still prefer a H-pattern gearbox instead of this one…