Gearbox gremlins to delay Mitsubishi dual clutch transmission

[swamp2]

Ugh.

Hopefully this has ABSOLUTELY no bearing on the progress BWM (and Getrag) and making with the DCT for the M3.

From Autoexpress.com 11/11/2007

Problems with Mitsubishi’s slick-shifting SST transmission will delay the delivery of the Evo X, according to reports from Japan. By Dan Strong 11th November 2007

Production difficulties with hi-tech SST gearbox may delay Evo X's arrival. The six-speed semi-automatic gearbox is one of the most capable on the market. But according to our sources, its complexity has meant mass-producing the unit is proving more difficult than expected. Initially, it was thought that production of cars with the transmission – which is similar to VW’s twin-clutch DSG gearbox – would begin this month in Japan. However, insiders now believe that because of reliability glitches, the first SST models won’t roll out of the factory until early next year, delaying their arrival in the UK until summer. Officially, Mitsubishi claims that there are no problems. The company insists that the Evo X will be available with both the SST gearbox and a more conventional five-speed manual unit from its UK launch in March. A first for the company, SST – which stands for Sport-Shift Transmission – offers the driver three increasingly responsive modes, ranging from Normal to Sport to Super-Sport, with the last of these holding the engine to the red line before changing up. The driver can take over at any time thanks to F1-style steering wheel-mounted paddles. The gearbox will ensure the car steals a march on its arch-rival, Subaru’s Impreza STI, which is only available with a conventional manual transmission. Sales of the Evo X get underway in spring, with prices from £30,000.

[lucid]

What makes you think there might be a connection here? Who is building the Mitsubishi transmission? Any relationship to Getrag? Am I missing something?

[swamp2]

Originally Posted by lucid

What makes you think there might be a connection here? Who is building the Mitsubishi transmission? Any relationship to Getrag? Am I missing something?

Sorry, I was not to clear on this. I did not mean there is any connection on the supplier sides nor OEM sides. I just meant to say that if the darn things are so tough to build and get to market maybe BMW will have problems just like Mitsubishi has. No causal connection at all though.

Fingers crossed....

[lucid]

Do you know if the VW had issues with getting its automanual mass produced.

On a related note, on reliability, which is my main concern with BMW's first generation DCT, I just read C&D's 40000 mile report on their fleet 2006 GTI. I looked out for specific DCT issues. Although they cited many issues with other things, there was no mention of any DCT or engine trouble. So these things can be reliable if they are designed well I guess.

[Epacy]

Originally Posted by lucid

Do you know if the VW had issues with getting its automanual mass produced.

On a related note, on reliability, which is my main concern with BMW's first generation DCT, I just read C&D's 40000 mile report on their fleet 2006 GTI. I looked out for specific DCT issues. Although they cited many issues with other things, there was no mention of any DCT or engine trouble. So these things can be reliable if they are designed well I guess.

While you can draw some conclusions from that, the DCT partner for BMW is believed to be different than the one used for VW.

[lucid]

Originally Posted by Epacy

While you can draw some conclusions from that, the DCT partner for BMW is believed to be different than the one used for VW.

Sure I realize that. I am just trying to evaluate the technology in general. I can't imagine the specific implementations are vastly different although I haven't seen any detailed documentation on any of these systems.

[JEllis]

Not worried...

[Epacy]

Originally Posted by lucid

Sure I realize that. I am just trying to evaluate the technology in general. I can't imagine the specific implementations are vastly different although I haven't seen any detailed documentation on any of these systems.

Well, they are different. How you use vastly is subjective. Obviously, the GTI implementations of DCT are basically for low power/torque situations. Whereas the other examples we are discussing are for much higher values. We have learned that there must be changes to accomodate increased power/torque applications.

[lucid]

Originally Posted by Epacy

Well, they are different. How you use vastly is subjective. Obviously, the GTI implementations of DCT are basically for low power/torque situations. Whereas the other examples we are discussing are for much higher values. We have learned that there must be changes to accomodate increased power/torque applications.

I would assume the differences in torque ratings are associated with scalability and are dealt with by making parametric modifications. I was referring to fundamental configurational similarities that most likely exist among the designs. But again, I don't know if that is true since I haven't seen the details.

[swamp2]

Originally Posted by lucid

I would assume the differences in torque ratings are associated with scalability and are dealt with by making parametric modifications. I was referring to fundamental configurational similarities that most likely exist among the designs. But again, I don't know if that is true since I haven't seen the details.

Parametric modification is a common/modern way to do computer aided design of a family of models and should work for such transmissions. 400 Nm is not really all that much more for a gear, bearing or clutch to handle compared to 275 Nm. Slightly larger/stouter components or slightly improved materials should take care of that. Maybe some increased lubrication and cooling requirements as well. I think I heard somewhere that accomodating the 8400 rpm redline input was/is a big challenge (I could be making that up...very fuzzy recollection actually). That is really cranking fast though compared to 6500 rpm and one has to deal with rotational forces scaling with the square of the ratio of redlines, not just the ratio.