BMW exec foresees the demise of the DCT from the M3

[mrad01]

Originally Posted by SenorFunkyPants

Thats because you are doing it wrong.
You don't go barreling up to a hairpin in 5th, jump on the brakes then triple down-shift to 2nd......you down-shift *as* you brake.

Good to have the option! On an steep uphill hairpin you can ponce around doing your nice tap dance through the gears - but it is a pretty bloody short braking zone!! It does depend on the track.

On a flat hairpin - you are completely right.

[SenorFunkyPants]

You can do a triple down-shift if you like...as long as you have timed it correctly it will still work fine (and quickly) but its not something you do if you are properly on it.
High revs in 5th is fast, you would have plenty of time to down shift through every gear even downhill on full brakes.
The DCT is by no means perfect but it appears that your short drive has given you a poor understanding of how to use the system. Stick to what you know.

[Technic]

Originally Posted by captainaudio

I think that the article is predicting the demise of the DCT rather than manual transmissions. The torque converters on high performance ATs are out of the picture once the car gets moving and some of the newer designs replace the torque converter with a multi-plate clutch. The shift times of both a "converntional' AT and the DCT are so fast that further improvements are moot. Both types of transmissions are capable of shifting much faster than human reaction time and in fact both are faster than "The Blink of an Eye" whch is about 300-400MS.

I have driven the DCT in both the 335is and the M3 and found it to be an excellent transmission but did not find it to be significantly better than a good AT. IMO a lot the appeal of the DCT is that it does not carry the stigma of being a "Slushbox"



CA

x2

It is a much better automatic when you want it, it is as good or slightly better than a manual when you want it.

[OC3]

Originally Posted by SenorFunkyPants

You can do a triple down-shift if you like...as long as you have timed it correctly it will still work fine (and quickly) but its not something you do if you are properly on it.
High revs in 5th is fast, you would have plenty of time to down shift through every gear even downhill on full brakes.
The DCT is by no means perfect but it appears that your short drive has given you a poor understanding of how to use the system. Stick to what you know.

Indeed. Triple downshift in S mode is very fast. mrad01 must've been in D mode.

[_Jono_]

AMGs trannys suck

[RandyB]

It sounds like you guys will get a true automatic in the next M3 since the thing won't have to rev past 7,000 rpms anyways.

That's great to hear that they are still committed to offering a 6MT. Now they just need something woth while to put in front of it!

[Seven7]

Originally Posted by GhostRideTheWhip

....If anything it's the other way around. The 6MT would be the one that'll be going bye bye.....That article makes no sense to me.

+1

[Kyoshi71]

Originally Posted by GhostRideTheWhip

....If anything it's the other way around. The 6MT would be the one that'll be going bye bye.....That article makes no sense to me.

Yeah, I kind of got the same feeling.

[mkoesel]

Originally Posted by JusCruzin

Can anyone explain what Kretschmer means when he says that the disadvantage of DCT is that you can't have more than 7 gears without adding additional components? Is he essentially saying that if you wanted an 8 speed dual-clutch you would have to add a third wet clutch? I just don't know enough about dual clutch transmissions to understand what he is saying there.

Quite simply, he is talking out of his ass. This guy clearly has an agenda, and like the idiot running BMW in Canada, he is making shit up in some ego driven attempt to steer the direction of the company.

"In the future, it may be hard for double-clutch transmissions, because they will always be limited to seven gears," he says.

He's a complete moron. That's some powerful crystal ball you have there, dickweed.

But the dumbest part of it is this: a manual transmission is no more easy to add more ratios to than a DCT. So, if the lack of ratios will be the death of DCT, then what does that spell for the manual? An even more certain death, you dunce.

Now do I believe it will play out like that? Not necessarily, but this guy is simply not making sense with his arguments.

Also, anyone have more info on BMW's newest 8-speed automatic? Is this a torque converter automatic?

Yes, and a damn good one from what I have read. But that does not mean the DCT is going away. On the contrary, from what we know, BMW will employ a DCT for the new M5, and rumors talk of 8 speeds. Of course, that's not confirmed yet, so we'll see.

Originally Posted by piloto

To add an 8th gear to a DCT, you'd need to add the physical gears, plus extend the various shaft involved to accomodate them. You're also going to increase the physical size of the transmission.

Not necessarily, given that the transmission already supports 4 speeds via one of the two auxilliary output shafts. A fourth gear could be added to the other one as well, and with clever packaging, theoretically the transmission could be kept virtually the same size and weight. Yes, there is reverse in there too, but AFAIK that is handled by a seperate shaft.

With a planetary gear traditional slushbox, you can create the additional ratios without adding further (physical) gears.

That's true to some degree. AFAIK they are still using three planet gerars with each sun gear. You might be able to add more, but it comes at the expense of reliabilty. So, you can still only get so many ratios from a given planetary set. That said, Mercedes and others have 9 speed autos in the works.

[ns2000x]

Originally Posted by captainaudio

To put exactly how fast 200 Milliseconds actually is this reaction time test may put things into perspective.

http://www.humanbenchmark.com/tests/...time/index.php

CA

THat was fun.
I did 5 tries and averaged 232ms, and my fastest was 197ms.
I'm sure I could improve, but it just goes to show.

[RevFreak14]

Can't see how this would be possible. If anything it would be the other way around. Ferrari is putting auto gearboxes in all their cars now. I think if anything this is the future and manuals may become a thing of the past as time goes on.

[PKL]

6MT FTW!

[MMMorish]

Originally Posted by mrad01

I think you are right to say that DCT autos are here to stay. My dealer has loaned me a DCT auto M3 while my 6MT gets a new crank and bottom end bearings (!!) - and the experience of driving is interesting...

Accelerate - wow, what a rapid gearchange - very impressed!!!

Change down - what? How slow is that!!!!

Try to go from 5th to 2nd gear in a hairpin quickly. Suck!!! The downshift is shocking...

How about reversing out of a tight garage when the engine is cold? That is an experience. Need to be up around 2500rpm to get the auto computer clutch to engage. Bad.

DCT auto has quite a bit more development to go before it can be considered "overall" better than the 6MT, but the shifting up speed shows the potential...I'll let all the DCT auto buyers of today do all the R&D and I'll buy one when they are ready.

[yes, I know DCT is dual clutch transmission, but no where does it say manual. Looks like an auto, drives like an auto, changes for you like an auto --- so it must be an auto. It even has D,P,N, R]



BTW, all 2008 M3s will need their cranks replaced at some point. It was fixed November 2008. Just go to realoem.com and put in your VIN. Go to the crank assembly and see if the bearings and crank for your model have a new part number and the original numbers STOPPED. Scary.

Can you please explain this further? Will it be covered under warranty?

[SenorFunkyPants]

I drove a 997 c2s gen 2 PDK back to back with my DCT M3 and I thought there wasn't much in it...if anything the DCT had the edge.

[persian54]

Originally Posted by captainaudio

To put exactly how fast 200 Milliseconds actually is this reaction time test may put things into perspective.

http://www.humanbenchmark.com/tests/...time/index.php

CA

cool

I'm in 31st place for the day

[Steveo]

Lambo's new car due soon shifts in 50 MS!

http://www.evo.co.uk/news/evonews/25...t_details.html

[mkoesel]

Originally Posted by Steveo

Lambo's new car due soon shifts in 50 MS!

http://www.evo.co.uk/news/evonews/25...t_details.html

That's cool, but they are hyping this "ISR" as a major advance, when in reality a DCT already does essentially the same thing. Also, Ferrari already has a 50ms shifting in the Scuderia, and it probably does something similar to what Lamborghini is doing. Either way, you still cannot have both gears engaged at the same time since there is only one clutch and output shaft. So it is still slower to execute the overall shift than a DCT.

Someone should build a DCT that uses planetary gear sets. Not sure why that hasn't been attempted yet. It would be no less complicated than a traditionaly automatic, and in theory shift faster.

[M3Fool]

I LOVE my MDCT.... not clunky at all around town. This makes no sense.... is F1 going to go back to manuals as well???

[Edward]

Originally Posted by M3Fool

I LOVE my MDCT.... not clunky at all around town. This makes no sense.... is F1 going to go back to manuals as well???

well, F1s are sequential....a lot more like manuals than DCT to begin with.

The only concerns I have for the future of DCT (huge fan of DCT btw), are longevity/reliability in production cars and capability to handle torque.
But still, the 458 Italia, California and Veyron all use DCT and all of those have good amounts of torque so I'm not sure where that concern stemmed from in the first place.

Also, I have no idea where the notion that DCT is clunky around town came from. It's beyond smooth in all operating modes. The only thing that could be fixed is the software issue of engagement lag when going from any forward gear to reverse. Sometimes the car acts like it's in neutral and just rolls forward when you're already in reverse gear.

[duk]

6 ot 7MT!

[mrad01]

Originally Posted by SenorFunkyPants

You can do a triple down-shift if you like...as long as you have timed it correctly it will still work fine (and quickly) but its not something you do if you are properly on it.
High revs in 5th is fast, you would have plenty of time to down shift through every gear even downhill on full brakes.
The DCT is by no means perfect but it appears that your short drive has given you a poor understanding of how to use the system. Stick to what you know.

Except I've had the DCT for over 4 weeks now.....short drive - sorry, no.

Understand how the system works? Yes.

I suggest you get someone to read the posts to you - I said UPHILL not down. Stick to what you can comprehend.

Changes the game somewhat due to gravity.

[mrad01]

Originally Posted by MMMorish

BTW, all 2008 M3s will need their cranks replaced at some point. It was fixed November 2008. Just go to realoem.com and put in your VIN. Go to the crank assembly and see if the bearings and crank for your model have a new part number and the original numbers STOPPED. Scary.

Can you please explain this further? Will it be covered under warranty?

It is covered under warranty in my case because the car was under the NZ Premium Selection cover. It started to have knocking noise at startup when cold. I recorded 5 of these and sent them to BMW who first replaced the VANOs check valves. When that did not fix it, the took out the crank to find worn bottom end bearings. The crank had some small marks on it too. BMW NZ came and inspected the parts, reported their findings back to germany who said "Replace the lot". You will find that BMW will only replace it if there is a reported and confirmed fault with YOUR car.

Seems I'm not the only one and that the "issue" was fixed on the 10/2008 according to realoem.com. Here is the screenshot from their site - you will see most of the crank parts are ENDED and have a new part number.

My car has done 30,000kms (I don't know/care what that is in that old fashioned "miles" thing)

That's the reason I have had this DCT auto M3 for the last 4 weeks...and counting...