Best term for the M-DCT transmission in the M3

[mkoesel]

Originally Posted by goldminer

I have seen someone on this board (possibly you) expain this before and I still have no idea what you think the H gate would do.

Wasn't me.

The computer has to have control over the selection of the next gear in this type of transmission. The computer will have already pre-selected that next gear long before you even reach for the shift gate.

The computer does not select the gear - I do. The computer anticipates the next gear, and prepares for it. But if you skip gears then it must "abort" and adjust.

You can't have the H-gate actually selecting the gears the way a normal transmission would do. It would defeat the whole purpose and all of the advantages of the transmission type.

No. The H-gate would do _exactly_ the same thing as multiple clicks on the paddle or shift lever would do. Nothing more, nothing less.

If your idea was really better F1 cars would still have stick shifts in them and not steering wheel paddles.

Never said it was better - just it would be nice.

Also, clearly If F1 was the model here then there would be no stick on the console either.

[southlight]

Originally Posted by swamp2

A good intro to sequential boxes is here. They also have many other good articles on other type of trannys as well.

Sure no H gate. Why - isn't that obvious? The M-DCT system pre-selects the next gear. Would you want both the ability and requirement to constantly be choosing your "next" gear. Can you do this as fast as the computer+hydraulics? You would be right back to square one with shift times comparable to a MT. As implemeted either via paddles or the stick M-DCT is in some ways sequential. In all modes except kick down it requires n clicks to move n gears. However inside the box it is skipping the gears. So the interface is sequential (with one exception) but the operation/function internally is not sequential and is better.

With all well-deserved respect for the DCT that one exception is totally unacceptable. There should be no kick down in the S modes!


Best regards, south

[ersin]

Originally Posted by southlight

With all well-deserved respect for the DCT that one exception is totally unacceptable. There should be no kick down in the S modes!


Best regards, south

Is this true? The SMG didn't kick down until you were like 5 mph or less. Real kick down should be reserved for auto modes only. I really have a hard time believing the S modes of DCT kick down when you give it throttle.

[southlight]

Originally Posted by ersin

Is this true? The SMG didn't kick down until you were like 5 mph or less. Real kick down should be reserved for auto modes only. I really have a hard time believing the S modes of DCT kick down when you give it throttle.

To clarify: No kick down when giving throttle, but it engages the lowest possible gear after you've pushed the down paddle once. I think most might like that feature, but it's one step further away from driver's full control.


Best regards, south

[ersin]

Originally Posted by southlight

To clarify: No kick down when giving throttle, but it engages the lowest possible gear after you've pushed the down paddle once. I think most might like that feature, but it's one step further away from driver's full control.


Best regards, south

So, you're in fifth, say, then you want to down shift to fourth and click the left paddle once. But instead of going into fourth, it might go into second? If that is the case I don't like it either. Just FYI, the SMG was not like this.

[goldminer]

Originally Posted by mkoesel

The computer does not select the gear - I do. The computer anticipates the next gear, and prepares for it. But if you skip gears then it must "abort" and adjust.


No. The H-gate would do _exactly_ the same thing as multiple clicks on the paddle or shift lever would do. Nothing more, nothing less.

You don't select the gear in M-DKG. The gear is already pre-selected by the computer. The computer does not "anticipate" the next gear, and "prepare" for it. It engages the next appropriate gear on the other layshaft, long before you ever ask for the shift. When you hit the paddles you are simply switching from one clutch to the other.

If the computer has misjudged the gear you wanted to be in then having an H-pattern shifter is not going to change that. It is just going to slow down your shift.

You have 2 input shafts and 2 layshafts driven by 2 independent clutches in a DSG/DKG type transmission. This is basically 2 independent transmissions in one housing. You cannot select the gears for this 2-tranny setup with a single H-pattern shifter. The computer must coordinate the two. Having a stickshift would just be a different, and very awkward, way of switching between clutches. You would not be able to row your way through an H-pattern skipping gears and you would still need to rely on the computer to recognize that the gear selected was not what the driver wanted and to select another one.

[swamp2]

Originally Posted by southlight

To clarify: No kick down when giving throttle, but it engages the lowest possible gear after you've pushed the down paddle once. I think most might like that feature, but it's one step further away from driver's full control.


Best regards, south

"Kick down" meaning shifting to the gear that will provide maximum acceleration is a user controllable feature. When in S (manual mode) kick down only happens on the application of full throttle and a downshift command via paddle or lever. Seems perfect to me. How else would you go from 7th to 3rd for a near instantaneous change from an even highway cruise speed to max acceleration? Four clicks of the paddle?

South I know you know this one but for others kick down in S modes is entirely unrelated to automatic down shifts in S modes. Here the car will downshift at extremely low rpms during braking to prevent a stall. Again, a perfect feature IMHO.

[swamp2]

Originally Posted by goldminer

You don't select the gear in M-DKG. The gear is already pre-selected by the computer. The computer does not "anticipate" the next gear, and "prepare" for it. It engages the next appropriate gear on the other layshaft, long before you ever ask for the shift. When you hit the paddles you are simply switching from one clutch to the other.

If the computer has misjudged the gear you wanted to be in then having an H-pattern shifter is not going to change that. It is just going to slow down your shift.

You have 2 input shafts and 2 layshafts driven by 2 independent clutches in a DSG/DKG type transmission. This is basically 2 independent transmissions in one housing. You cannot select the gears for this 2-tranny setup with a single H-pattern shifter. The computer must coordinate the two. Having a stickshift would just be a different, and very awkward, way of switching between clutches. You would not be able to row your way through an H-pttern skipping gears and you would still need to rely on the computer to recognize that the gear selected was not what the driver wanted and to select another one.

Agree and disagree. First two paragraphs are correct.

As far as an H gate DCT it would be possible. The H gate would not be a mechanical connection to the gearbox just as the current transmission tunnel lever is not - it is just an electrical switch. Such a configuration could control one or two clutches and could allow gear skips as well. But again back to my earlier post on this point there would be no point to a design of this type. Slower, more confusing and would interfere with the softwares pre-selection of the next gear.

[goldminer]

Originally Posted by swamp2

Agree and disagree. First two paragraphs are correct.

As far as an H gate DCT it would be possible. The H gate would not be a mechanical connection to the gearbox just as the current transmission tunnel lever is not - it is just an electrical switch. Such a configuration could control one or two clutches and could allow gear skips as well. But again back to my earlier post on this point there would be no point to a design of this type. Slower, more confusing and would interfere with the softwares pre-selection of the next gear.

I don't think that we really disagree at all. My point was that a conventional H-shifter with direct mechanical or cable connection to the shift forks would be impossible in a DKG type of tranny. Your description of a faux shifter actuating electrical switches was what I meant when I said

"Having a stickshift would just be a different, and very awkward, way of switching between clutches."

[southlight]

Originally Posted by swamp2

"Kick down" meaning shifting to the gear that will provide maximum acceleration is a user controllable feature. When in S (manual mode) kick down only happens on the application of full throttle and a downshift command via paddle or lever. Seems perfect to me. How else would you go from 7th to 3rd for a near instantaneous change from an even highway cruise speed to max acceleration? Four clicks of the paddle?

South I know you know this one but for others kick down in S modes is entirely unrelated to automatic down shifts in S modes. Here the car will downshift at extremely low rpms during braking to prevent a stall. Again, a perfect feature IMHO.

You're right (as is DCT) in performance orientated situations. But I think there still should be the choice of not having such multiple shifts. Besides that four clicks on a PC racing sim steering wheel is really fun, reckon it's the same for the real deal.


Best regards, south

[footie]

Originally Posted by southlight

To clarify: No kick down when giving throttle, but it engages the lowest possible gear after you've pushed the down paddle once. I think most might like that feature, but it's one step further away from driver's full control.


Best regards, south

That comment reaffirms the basic argument between a conventional stick shift and DCT, regardless of whether it's better in terms of efficiency which we all know it is the fact remains that you have lost a little bit of the control and connection you once had.

Also hearing how good this thing is in full automatic mode I reckon you (the driver) will be hard pressed to improve on the decisions that the gearbox makes for itself, so best to lay back and enjoy the ride.

[!Xoible]

i like it how people wanna stick-shift-ify DCT... it's not, get over it.

real cars have a 3rd pedal, real men drive 6MT... that's it.



JKJK... im kidding i promise

[ebschor]

+1

I told my wife "Don't worry, you can drive it." That's all she wanted to hear. I couldn't buy a Viper unless I got a divorce... wait, isn't that what they're for?

[oneginee]

Originally Posted by ///Mantis

i like it how people wanna stick-shift-ify DCT... it's not, get over it.

real cars have a 3rd pedal, real men drive 6MT... that's it.



JKJK... im kidding i promise

+100


Who gives a damn how DCT is called or should be called, the OP should have called his thread "who can be more pedantic than me pondering over a more suitable name for DCT ?". The real question is what's best in your opinion 6MT or DCT and why.

[swamp2]

Originally Posted by ///Mantis

i like it how people wanna stick-shift-ify DCT... it's not, get over it.

A big +1. Good insight from a 6MT guy.

Originally Posted by ///Mantis

i like it how people wanna stick-shift-ify DCT... it's real cars have a 3rd pedal, real men drive 6MT... that's it.

A big -1

Originally Posted by ///Mantis

JKJK... im kidding i promise

[swamp2]

Originally Posted by oneginee

Who gives a damn how DCT is called or should be called, the OP should have called his thread "who can be more pedantic than me pondering over a more suitable name for DCT ?". The real question is what's best in your opinion 6MT or DCT and why.

The votes and views justify the question.

The ensuing discussion has been good IMO.

Just in case you missed it your question has been absolutely BEATEN to death here on the forum. Nonetheless some very good discussion.

Don't like the thread/poll/topic feel free to . No need to toss around inflamatory labels and sarcastic insults. Well depending on your age and maturity, perhaps...

[mkoesel]

Originally Posted by goldminer

You don't select the gear in M-DKG. The gear is already pre-selected by the computer. The computer does not "anticipate" the next gear, and "prepare" for it. It engages the next appropriate gear on the other layshaft, long before you ever ask for the shift. When you hit the paddles you are simply switching from one clutch to the other.

You're saying the same thing in a different way. No need to keep rehashing this. We both understand how the transmission works.

If the computer has misjudged the gear you wanted to be in then having an H-pattern shifter is not going to change that. It is just going to slow down your shift.

Maybe it will slow down the shift. But so will taking your hand from the wheel to grab the shifter on the center console, and yet that is still provided also.

[mkoesel]

Originally Posted by swamp2

As far as an H gate DCT it would be possible. The H gate would not be a mechanical connection to the gearbox just as the current transmission tunnel lever is not - it is just an electrical switch. Such a configuration could control one or two clutches and could allow gear skips as well. But again back to my earlier post on this point there would be no point to a design of this type. Slower, more confusing and would interfere with the softwares pre-selection of the next gear.

I disagree that it would have to interfere with the software swamp. Like we've both said, its just an interface - pure electronics. Pushing the lever to the various positions in the gate would be exactly identical to pushing the lever in the current car repeatedly. I do agree that it could be a more error prone process. The sole advantage would be to provide an interface that traditional manual users might feel more at home with. It would even be possible to engineer a shifter that could function both in an H gate pattern and the up/down shift pattern that the lever in the production car uses.

[sayemthree]

I would call it a
sequential, automated, double clutch, fast-ass shifting automatic.

hmmmm - or how about Double Clutch Transmission (DCT) - how novel.

[sayemthree]

BTW I think F1 uses SMG type technology.

[!Xoible]

Originally Posted by ebschor

+1

I told my wife "Don't worry, you can drive it." That's all she wanted to hear. I couldn't buy a Viper unless I got a divorce... wait, isn't that what they're for?

YOU FOUND IT!!! congratulations!

DCT is best described as "the car my wife can drive"

[sayemthree]

Originally Posted by ///Mantis

YOU FOUND IT!!! congratulations!

DCT is best described as "the car my wife can drive"

LOL - thats funny

- except my wife drives a MT!!!!