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      07-29-2019, 04:03 AM   #136
kyrix1st
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Drives: G87 M2; E92M3 MT&DCT; M3 euro
Join Date: Sep 2014
Location: nyc

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2004 BMW Z4  [0.00]
Quote:
Originally Posted by pbar View Post
Talking about "Shift speed", rather than responsiveness is part of the problem. People who have never driven a DCT in 'manual' mode aren't even aware how annoying it is to have lag between a paddle input and a gear change.

An M-DCT box is marketed as an "automated manual" - i consider it a fly-by-wire version of a manual transmission where I don't need to use levers and pushrods to make something happen, and the mechanical parts move a lot faster. I don't need to take my hand off the steering wheel and waggle one foot around in the air to feel driver engagement.

BUT... driver engagement depends crucially on the fact that my input timings matter. When I want to downshift, it has to happen now.

So, can we please try to get away from the 6MT "purists" saying "if I don't use a stick then all auto transmissions are the same" and "the ZF changes gear really fast and smooth". That's basically irrelevant to me.

I am prepared to hope that M-division includes some test drivers who feel the same way I do. Perhaps they will tweak the ZFat to be more responsive to inputs than all existing incarnations. If not, I'll be looking elsewhere.
Porsche uses DCT not because it's auto, but because it's the best performer with immediate response to user inputs for BOTH upshifts and downshifts.

ZFat can barely rev over 7,000 rpm due to oil cavitation at high rpm and refuses to downshift near redline which translates to shitty paddle response. BMW doesn't use it because it's the fastest transmission, they use it because it's the cheapest all rounder. They could have used AWD R&D revenue instead on refining low speed driveability of DCT(close to that of PDK), but they didn't. There is nothing mechanically distinguishing from Audi.

AMG nowadays adopts DCT into their purest cars, fast to respond to user inputs and they are about ten steps above in terms of luxury so I rate them unequivocally higher quality than BMW M.

Just go to ZF's homepage and read their descriptions on DCT and 8 speed steptronic. Their DCT is labeled "sporty transmission" while ZFat is "comfortable and efficient".
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Last edited by kyrix1st; 08-01-2019 at 05:27 AM..
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