What is SMG on the Z4?

RichLove · Post by **RichLove** » Thu 28 Aug, 2008 07:57

Hello guys

I'm new here and thinking about buying a 3.0 Z4 - probably about a 2004.

I am a little confused about the automatic gearbox options on this car and whether they are essentially all SMG?

I have done a search on the forums and google but can't find the exact information that i am looking for.

I test drove an M3 some months ago and since then my thoughts were that the SMG relates to the gearbox which has sequential shifting via the gear stick OR steering wheel paddles.

I notice that you can get a Z4 with automatic gearboxes that also allows sequential shifting forwards and backwards via the gear lever but with no steering wheel paddles - is this still SMG? I notice also that some Z4s do have the steering wheel paddles - is this still the same gearbox but with an added (cost?) option of shifting with the steering wheel paddles - or is this a completely different gearbox system?

If somebody with the knowledge could please clarify the automatic / SMG gearbox options available on the Z4 (perhaps with any significant changes throughout the model life time) or point me in the right direction, I would be very appreciative.

Many thanks
Rich

tetchmeister · Post by **tetchmeister** » Thu 28 Aug, 2008 08:47

SMG on the Z4 is a 6 speed manual gear box with an automated clutch. Gear changes can be made in auto mode where the car decides or in manual mode where you use paddles or the gear stick. SMG cars come with steering wheel paddles as standard, there are not many SMG's around.

Automatic is a fully automatic gearbox with torque converters etc, you can use it in fully automatic mode, or you can use the paddles or stick to force a gear change. Auto cars had an option for steering wheel paddles. There are loads of Autos around.

The SMG was discontinued after the Z4 face lift when the new engines arrived.

RichLove · Post by **RichLove** » Thu 28 Aug, 2008 10:13

Hi tetchmeister - thank you for the information - much appreciated.

I am still a little unclear however.

There is an automatic gearbox and an SMG - which are two different things. Each has a fully automatic mode, each can be used to change gear by shifting forward and backwards with the lever and both can potentially use paddle levers (and each has a sport mode?). So, given all of these similarities - I am a little unclear what the differences are, which, if either, is better, the difference in feel to drive each?

Where does Steptronic fit in to the mix?

spokey · Post by **spokey** » Thu 28 Aug, 2008 10:16

tetchmeister wrote:SMG on the Z4 is a 6 speed manual gear box with an automated clutch.

Hello, stranger! Where have you been? Too good for us now that you have a Lotus?

RichLove · Post by **RichLove** » Thu 28 Aug, 2008 10:43

Hi tetchmeister - thank you for the information - much appreciated.

I am still a little unclear however.

There is an automatic gearbox and an SMG - which are two different things. Each has a fully automatic mode, each can be used to change gear by shifting forward and backwards with the lever and both can potentially use paddle levers (and each has a sport mode?). So, given all of these similarities - I am a little unclear what the differences are, which, if either, is better, the difference in feel to drive each?

Where does Steptronic fit in to the mix?

///M_aniac · Post by **///M_aniac** » Thu 28 Aug, 2008 10:47

See here -

http://www.bmw.com/com/en/insights/tech ... ronic.html

Lots of information in the BMW technology guide.

C

pop_sausage · Post by **pop_sausage** » Thu 28 Aug, 2008 10:58

RichLove wrote:Hi tetchmeister - thank you for the information - much appreciated.

I am still a little unclear however.

There is an automatic gearbox and an SMG - which are two different things. Each has a fully automatic mode, each can be used to change gear by shifting forward and backwards with the lever and both can potentially use paddle levers (and each has a sport mode?). So, given all of these similarities - I am a little unclear what the differences are, which, if either, is better, the difference in feel to drive each?

Where does Steptronic fit in to the mix?

The SMG is a manual box with automatic actuations. It is designed for those who want F1 Style changes - which means they can be jerky and cumbersome to use in everyday driving - the computer trys and emulate an autobox. People have reported though how good it is when you're on it and how bad it can be in stop start town environment. I've also heard many problems with SMG2 box and BMW have now scrapped this system for the duel clutch type box. I certainly wouldn't buy one without a warranty.

The Auto Box is and Auto box with manual control - there's a torque converter and a planetary gear system like all other autos - this is a silky smooth gear change, but not nearly as 'sporty'. You will get lag from the torque converter - something I don't mind in, say, a 5er, but in a sports car seams a little wrong IMO (

) - but, you do hit your 0-60 time, every single time which is hard to do in a manual.

What do you want? Track toy/Sunday morning blaster or a daily commuter?

RichLove · Post by **RichLove** » Thu 28 Aug, 2008 14:28

Probably would like a bit of all of those - but not sure if i would take it on a track

OK - I think that helps to clear it up.

I have read a few threads of SMG vs manual with quite a few people favouring the SMG but I read the threads with the viewpoint that SMG and Auto were the same thing.

Is there a general feeling about the manual vs the auto transmission?

I would be quite tempted by the SMG and manual is fine but not sure how much less sporty etc a 'normal' auto would be - not sure i would like that

I would be interested to know what 'manual' shifting (i.e. pushing the lever forward or backwards) is like with the SMG compared to the 'normal' auto?

Apolyon · Post by **Apolyon** » Thu 28 Aug, 2008 15:13

And there was me hoping it stood for the Sub-Machine Guns which pop down from the side indicators for use against people who cut you up.

Well I am not changing to a Z4 until they add that feature, and thats that.

tetchmeister · Post by **tetchmeister** » Thu 28 Aug, 2008 15:36

spokey wrote:
tetchmeister wrote:SMG on the Z4 is a 6 speed manual gear box with an automated clutch.
Hello, stranger! Where have you been? Too good for us now that you have a Lotus?

Not at all old boy, i come around most days, just don't have much to say usually. You know me, shy, quiet and all that...

tetchmeister · Post by **tetchmeister** » Thu 28 Aug, 2008 15:46

RichLove wrote: I would be interested to know what 'manual' shifting (i.e. pushing the lever forward or backwards) is like with the SMG compared to the 'normal' auto?

For the SMG it feels like a standard manual gear change, only much faster, most people only experience a jerky ride if they don't lift the gas pedal slightly when changing gear, (which you would do naturally in a manual, only to a greater extent) In Sport mode gear changes are exceptionally fast.

On the AutoBox it feels like an auto box changing, ie nothing really happens, just the engine speed is faster or slower after the shift.

I never used auto mode when i had the SMG, i found that i chose the correct gear much better than the computer did, mostly because i knew what was going to happen next.
Driven in manual mode, (ie you selecting the gears all of the time like you do in a manual) the SMG is the best of all worlds, faster than both the Manual and the Auto gearboxes and driven correctly as smooth as an Auto. And changing gears with the paddles is fun and not at all taxing.

The only issue may be with reliability. Mine broke within 3 months, but the replacement was faultless for the next 3 years when i sold it.

Given the choice i would always go for an SMG over any other gearbox. (and did.) In fact it is the only thing i miss about the Z that i owned. (that and the sensible sized fuel tank.)

greg_ch · Post by **greg_ch** » Thu 28 Aug, 2008 15:57

I had a 2004 3.0 SMG for a couple of years before the Z4 ///M. Here is something I posted a while back on my experiences. On reflection I would still have preferred the Z4 ///M with SMG. You could say I'm a convert.

greg_ch wrote:I loved my SMG. It was:

- Fast
- Accurate, you always have the best gear selected
- Engine revs matched automatically, with a lovely throttle blip built in to the change.
- Genuine left foot braking
- Safer, as you never need to take your hands of the wheel
- Smooth in manual mode. Shifting could be done with paddles on the steering wheel or gear stick.

Further more even when compared to faster cars i.e. DavidM's old M Roadster it never failed to keep up with the exception of a strait line drag. Mostly because you are always in the right gear.

On the downside the automatic mode was not very smooth. I only really used it if I was in a traffic jam in town or on the motor-way. It would be great to be in 6th and push the leavers back twice for a 4th gear overtake.

To be honest I held back on the ///M until BMW officially confirmed SMG would not come. I really wanted SMG on the ///M. The reason it's not in btw is that it would have been too expensive and time consuming to engineer in to the ///M. I am sure it will be back on the Z4 replacement in 2011.

Tim the admin here also has SMG and although it's been a couple of years since I have seen him he was very enthusiastic about it when in Switzerland in 2004.

If you have any more questions just let me know.

RichLove wrote: I read the threads with the viewpoint that SMG and Auto were the same thing.

This is NOT correct.

The Z4 SMG uses the same 6 speed manual gearbox and clutch as the manual car. The only difference is that the clutch is hydraulically actuated by an electronic instruction and not your foot! SMG cars have an automatic mode, but it is no where near as refined as an automatic box. Power is cut for very short period of time and naturally peaks when it comes back. This can give a feeling of the change being rather jerky.

There was some confusion after the facelift because BMW added the SMG paddles to the steering wheel of automatic cars, in the same way many Audi's of that generation had Tiptronic paddles.

You can drive the SMG on the rev limit in manual mode, the automatic will force you to change up. What the SMG will not let you do is change down from 6th to 2nd at 150mph, something you could technically do in a manual but really wouldn't want to!

The SMG is perfectly smooth providing you don't use the auto mode on anything other than the motorway. All you need for a perfectly smooth shift is a soft lift, during the change.

RichLove wrote: I would be quite tempted by the SMG and manual is fine but not sure how much less sporty etc a 'normal' auto would be - not sure i would like that

The automatic will be less sports in the sense that:

- the torque converter robs the drivetrain of some power at the top end and during accelerations

- the system is relatively slow changing gear

- the system imposes much stricter rev limits i.e. it will automatically shift up when you are too close to the rev limiter

RichLove wrote: I would be interested to know what 'manual' shifting (i.e. pushing the lever forward or backwards) is like with the SMG compared to the 'normal' auto?

In terms of feel the difference is this. With the automatic gearbox you need to move the lever on the transmission tunnel to the left, before you can push it back or pull it forward. I would say the spring tension was about the same. I also had a 2004 BMW with the same automatic gearbox as the Z4 at the same time.

On SMG cars you can simply push or pull the leaver, saving you a step. It is also possible to do this via the paddles on an SMG car. This means it's very easy to go from a relaxed driving style to a more of focused and engaged style.

Regarding maintenance and running costs.

The SMG is the most fuel efficient of all three versions. On the flip side maintenance is potentially more expensive. I generally reach boredom threshold at about 2 - 3 years, so my cars are always in warranty. When the SMG system went on my Z4 2004 it took the engine with it. The warranty bill was close to GBP 20K. I don't buy used cars, but if I were looking for a used Z I would only look at the auto or manual.

When comparing SMG and the manual box think of it like this. The loss of dynamic engagement with SMG is compensated by the speed and efficiency of the change. You have to decide which of those characteristics are is important to the way you drive.

RichLove · Post by **RichLove** » Fri 29 Aug, 2008 07:35

Guys - absolutely top answers, thank you very much for the clarification, information and subjective descriptions of each of the systems.

Given all of the above - I think that manual might be the one for me. I like the idea of SMG but they seem quite rare and given that i would probably be getting an 04 it could be a bit of a risk. The automatic does appeal to me but I am not sure if i would find it too uninvolving.

tetchmeister - interesting that you say "In fact it is the only thing i miss about the Z that i owned. " - were you not overly impressed with the car generally?

Thanks again guys
Rich

tetchmeister · Post by **tetchmeister** » Fri 29 Aug, 2008 10:56

RichLove wrote: tetchmeister - interesting that you say "In fact it is the only thing i miss about the Z that i owned. " - were you not overly impressed with the car generally?

Rich

Not at all, i enjoyed my Z a great deal, i'm just enjoying my Lotus more.

RichLove · Post by **RichLove** » Fri 29 Aug, 2008 14:37

What Lotus are you driving?

I was very tempted in to an Elise recently. I test drove a 111R but it didn't really do too much for me. I'd be interested to hear any comparisons and opinions you have of each.

tetchmeister · Post by **tetchmeister** » Fri 29 Aug, 2008 14:57

RichLove wrote:What Lotus are you driving?

I was very tempted in to an Elise recently. I test drove a 111R but it didn't really do too much for me. I'd be interested to hear any comparisons and opinions you have of each.

I have a Europa S. It is much more basic than the Z, but much more connected to the road.
The handling is not really comparable since the Z mostly handles well due to massive tyres and the Lotus due to great balance and low weight.
If you compare the two cars directly then the Z is more of a sporty tourer and the Lotus a softened track car.

I preferred the Europa to the Elise / Exige due to the turbo engine making driving a lot less frantic and the slightly softer ride making it a bit better as an every day car.

Of course these are only my non expert opinions and are not meant to be detrimental to anything or anyone.

spokey · Post by **spokey** » Fri 29 Aug, 2008 15:59

tetchmeister wrote:Of course these are only my non expert opinions and are not meant to be detrimental to anything or anyone.

RichLove · Post by **RichLove** » Mon 01 Sep, 2008 13:35

Thank you tetchmeister

I have been driving a turbo diesel for three years with quite lot of low down torque and it felt so different (in the Elise) to have to get to 6000+ revs to feel the extra power of the VVTi engine have any real impact and i didn't think that I would enjoy having to be doing that all of the time to really enjoy the car - i quite enjoy that surge of the turbo coming fairly low down the rev range

obviously the 3.0l z4 would be a different experience again but i am yet to drive one