[BIGTIME]

Hopefully I'll be picking up the above by the end of the month. Please can someone tell me how this gearbox works. I am not interest in the mechanics more just how you pull away, change gear, do you have to do anything to stop it stalling or rolling forward etc.

[doughboy]

So you've ordered one without test driving or reading about it???

Blimey,

Basically it only has 2 pedals and you drive it just like a normal auto (you have driven an auto at some point?)

[BIGTIME]

I have driven automatics before and was looking for a 6 speed auto 335i, but this 7speeder turned up and I have read rave reviews about it, but just wondered if it differed much from the 6 spead gearbox. I have put a deposit down that has held the car.

[G82Dude]

Well it's a robotised manual gearbox ala M3 SMG/M DCT/Audi (VW) DSG. Two clutches, a gearbox, some hydraulics and a computer! You can pop it in auto and it changes gears for you or use it in manual and change gears yourself. Note: it's not like a "classic" auto gearbox though and not a smooth as there is no torque convertor; it's a manual gearbox with the changes and clutch operation controlled by a computer.

PS it's rather good!

[creepy coupe]

Bigtime, you'll enjoy the DCT.As said already the basic pricaple is the same as an auto, you select drive and the car creeps forward, when you accelerate the gearbox changes up seamlessly.

You have a sport button just below the gear level, which sharpens throttle response and speeds up/down shifts slightly.

Knock the level over to the left and you have sport auto mode, which holds a given gear longer in the RPM range and changes with more ferocity, the gearbox will kick down when you gun the throttle

If you then move the level forward, you have full manual mode, which will only change via the steering wheel paddles and or by pushing the level forwards or backwards, in this mode the box will not kick down or change up in any gear, you can also select this mode with by pressing the paddles when in auto mode.

If you select manual mode via the paddles and don't change gears for a while, it will automatically go back to auto mode.

[RagingKileak]

I trust this is/will be available for the 135i too?

I have been seriously considering it in the near future... Will all the nice TV/much nicer looking screen options be in the 1 too?

Hmmm... Wrong place to ask I guess, and OT...

Matt

[BIGTIME]

Thanks for the replies. With the paddles is it pull lever to up a gear andpush to go down?

[creepy coupe]

Originally Posted by BIGTIME

Thanks for the replies. With the paddles is it pull lever to up a gear andpush to go down?

Are you taking the piss


http://www.e90post.com/forums/showth...=363642&page=2

[BIGTIME]

Are you suggesting I should have used the search facility?

[TMP]

Originally Posted by creepy coupe

If you then move the level forward, you have full manual mode, which will only change via the steering wheel paddles and or by pushing the level forwards or backwards, in this mode the box will not kick down or change up in any gear, you can also select this mode with by pressing the paddles when in auto mode.

So will the box not change up even if you hit the rev limiter? Assuming it must change down to prevent a stall....

[creepy coupe]

Originally Posted by TMP

So will the box not change up even if you hit the rev limiter? Assuming it must change down to prevent a stall....

I've not taken it to the rev limiter, so can't answer that, It does change down right at the last minute to prevent stall, but if you were say in 4th at 30 mph and floored it, it wouldn't change down and would take longer to build up speed, just like pulling away hard in the wrong gear with a manual car.

[Dougie335]

1/ Just watch when the car is cold. When you put it into gear it waits a second or two before automatically blipping the throttle. Then it starts to creep forward or back. The trouble is that within the second or two you think its not going to move so you apply the throttle only to find it then adds to the blip and you jerk away from stand still. Wait till its done the blip.

2/ Also watch when you apply a lot of throttle at low speed but in a high gear. Its like kickdown but the gearbox take a second or two to select a lower gear mean while the revs jump straight up to approx 5500revs. Most annoying when you just want to overtake say one car.

Dougie.

[sheps]

How are you getting on with the M3 Dougie?

[creepy coupe]

Originally Posted by Dougie335

1/ Just watch when the car is cold. When you put it into gear it waits a second or two before automatically blipping the throttle. Then it starts to creep forward or back. The trouble is that within the second or two you think its not going to move so you apply the throttle only to find it then adds to the blip and you jerk away from stand still. Wait till its done the blip.

.

Not sure what you mean by

When you put it into gear it waits a second or two before automatically blipping the throttle

When you say "put it in gear" do you selected another gear, or select a gear while stationary?

[Dougie335]

Creepy,
By putting it into gear I mean D or Reverse from neutral.

Dougie.

[creepy coupe]

Originally Posted by Dougie335

Creepy,
By putting it into gear I mean D or Reverse from neutral.

Dougie.

So why would it blip from Neutral to either 1st or reverse?

I understand the M3 DCT software to be different to the 335 Dougie, mine doesn't blip, it just creeps off like a traditional Auto.

[Dougie335]

Creepy,
I had two 335i's with DCT and both of them blipped the throttle when D or R was selected. Especially noticeable when cold.

Dougie.

[creepy coupe]

Originally Posted by Dougie335

Creepy,
I had two 335i's with DCT and both of them blipped the throttle when D or R was selected. Especially noticeable when cold.

Dougie.

Well mine desent, but I have had a gearbox software change, can't see why it would blip the throttle when going from neutral to either 1st or reverse as it would make the car surge forward/backward

[marcel b]

Originally Posted by TMP

So will the box not change up even if you hit the rev limiter? Assuming it must change down to prevent a stall....

yes, it does shift up automatically when hitting the rev limiter. in contrary to the M3 DCT.

[marcel b]

Originally Posted by uke92dude

Well it's a robotised manual gearbox ala M3 SMG/M DCT/Audi (VW) DSG. Two clutches, a gearbox, some hydraulics and a computer! You can pop it in auto and it changes gears for you or use it in manual and change gears yourself. Note: it's not like a "classic" auto gearbox though and not a smooth as there is no torque convertor; it's a manual gearbox with the changes and clutch operation controlled by a computer.

PS it's rather good!

this is not correct. the DCT cannot be compared to a SMG, completely different technologies. The SMG was indeed a "robotised" manual gearbox, the DTC is not, as it has 2 clutches. One for the even gears, one for the odd gears. The advantage is that when closing one clutch the other is already opening, meaning you can have a seamless gearshift without any loss of power / boost. This gearbox would be impossible to operate like a manual gearbox with 3 pedals.

[a1reader]

Originally Posted by creepy coupe

Well mine desent, but I have had a gearbox software change, can't see why it would blip the throttle when going from neutral to either 1st or reverse as it would make the car surge forward/backward

Mine doesn't blip when going into gear either. It only blips on downshifts

[G82Dude]

Originally Posted by marcel b

this is not correct. the DCT cannot be compared to a SMG, completely different technologies. The SMG was indeed a "robotised" manual gearbox, the DTC is not, as it has 2 clutches. One for the even gears, one for the odd gears. The advantage is that when closing one clutch the other is already opening, meaning you can have a seamless gearshift without any loss of power / boost. This gearbox would be impossible to operate like a manual gearbox with 3 pedals.

Oddly enough, I disagree, otherwise I wouldn't have posted what I did!

I am fully aware of the principal of dual clutch systems. They may be quite a novelty for BMWs (a Getrag 'box), but have been around a while for Porsche (PDK by ZF) and Audi/VAG (DSG/S Tronic by Borg Warner).

Just because it has 2 clutches doesn't change the fact that it is a clutch coupled gearbox with discretely selectable gears under a computer's control with the gear change and clutch management carried out hydraulically for you.

The advent of production car dual clutch gearboxes is simply the evolutionary stage we are currently at as a happy medium for economy, emissions and increased/improved driver involvement against an auto (SMG I was awful), as the single clutch 'boxes (I had 2 E46 SMG II M3s) were OK, but could be less than perfect if you didn't quite get the change right with the accelerator pedal. Having said that, I found it to be better and more involving than Audi/VAG's rather clinical (and boring) DSG/S Tronic or whatever they call it today. As an engineering exercise though, DSG is quite brilliant.

I wouldn't class a dual clutch 'box as an "automatic" gearbox. I find it manual in the sense that it has clutches, which are engaged or disengaged and gears which are selected. All of which is carried out robotically for you.

PS I didn't say you could drive a dual clutch gearbox yourself. Although if you have 3 legs/feet, it might be possible (an extra one for the extra clutch)...!