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      03-07-2019, 02:11 PM   #66
SleepingBMW
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Quote:
Originally Posted by chris719 View Post
Quote:
Originally Posted by SleepingBMW View Post
I have spent no time with BMWs DCT, only Audi, so i can't speak for it.

In my mind the ZF is nice for traffic. I don't like the feel, especially compared to the Audi. I do like the quality of life improvements. SMG having 6 settings is annoying to change when really I prefer Sport+ and eco. SMG also is annoying because the computer will hang at 2.9k revs for ever if the shift point is 3k for example where the ZF will shift to most economic for you.

I also like you can flappy paddle Down shift for a highway pass without exiting auto mode and it will revert back after 5 seconds or so. SMG will stay Manual forever if you downshift with a paddle. It also has Auto Manual and 'M' mode settings and is annoying to drive. Push M mode for some fun and it goes to whatever you program it to. Turn off M mode and it goes to whatever manual setting you have it to then you have to put it into Auto mode to get it back to auto. The computers in the new BMW transmissions are better in every Way.

However by the numbers, SMGIII is 65ms, DCT is 200 ms, and ZF is 220ms. This is all upshifts as well.

ZF has annoying traits for performance. at high torque settings it is not as fast or smooth. Just isn't. It can't skip 2 gears either and you have to do the mildly annoying shift wait shift. The kick down button on the pedal is incredibly annoying.

SMG isn't reliable or smooth but ZF is boring and an obvious compromise désignés to attract Camry buyers not track boys.

BMW should be bullied about it or you'll be stuck with it or something worse next generation. A transmission that works for hybrids and SUVs isn't going to be best for M cars. The Gord/GM 10 speed for example.
These numbers are wrong. There is no way that the BMW DCT is 200 ms. Those measurements don't even say if that takes into account software latency from paddle pull or the shift itself. Either way, DCT is basically instant unless you did something unpredictable. There's no way SMG III is 65 ms unless they are being measured in different ways. You can see just from Youtube videos it is a LOT slower than DCT or even ZF8. I found 3 videos in 5 min that show SMG III in an E46 M3 and the shifts are obviously slower. Maybe you think it's faster from the kick, but it isn't.
I'm going by BMW and Porsche's official numbers. You have to turn off traction control and activate the fastest setting for this. It's not fast at all in the default mode, maybe 500-600ms? I'm also not sure the M3 ever had SMGIII.

I'd say it's more likely you are confused by the lack of kick in the DCT and ZF8. I had spent some more time with the ZF8 in a 328d last week. It most definitely doesn't shift faster than SMGIII in highest setting, definitely a lot smoother though.

Unless ZF8 has a hidden setting? I was shifting in sport + with the shifter to manual mode. BMW likes to hide these things so it's possibly buried in the menu somewhere or M cars only?

Anyway ZF8 wasn't much of an improvement over ZF6. Same slushbox but apparently a complete redesign after that. Nice transmission compared to GM and Ford and the Japs, no doubt but I'd be mad if it was in my M car.

Remember BMW only uses it because it's rated for high torque, can run a hybrid, has no development fee, and is bought in bulk already. The alternative is developing a new DCT or manual for high horsepower only applications in M cars which sell under 20k and a small fraction of their market. They're not picking it because it's awesome, they certainly don't race with it. They just know they can save money without hurting sales by using it in M cars.

I also found out my SMG differential needs a $700 fluid change. Ouch.

Have the DCTs had expensive repairs?