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      10-13-2017, 09:05 PM   #1
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Question DCT vs Auto?

So now that the M5 has an Auto transmission vs the previous DCT. But it still has paddle shifters so my question is which is better? Would the auto with paddle shifters shift as fast as a DCT with paddle shifters? or does it shine when in auto mode only and the paddle shifters are just there if you want more fun and control?
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      10-13-2017, 09:40 PM   #2
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Which is better remains to be seen, I like many here remain skeptical of the ZF8 transmission but from everything that I have read it's set to be the best iteration of the transmission yet. lemetier has assured us that we will not be let down with how it operates. From what I can gather, the best iteration of this transmission currently is in the Alfa gulia QV and I've watched many reviews and specifically their nurburgring lap to see how it reacts to paddle inputs and it does seem very responsive. Frankly I could count on one hand the amount of times I've been in auto mode in the M5, I don't see just because it has a ZF8 i would not use the paddles.

Alfa claims 150ms for their ZF8 shift program however @lemetier said this in the main thread "Indeed no argument. F10 M DCT was 80ms at its fastest. The F90 has cut that by more than 1/3."

Here is the lap of the QV, pay attention to the paddles. The QV also has the exact same gear ratios and a 7k rpm redline so the shift points will be near identical.


Last edited by somer; 10-13-2017 at 10:01 PM..
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      10-13-2017, 10:15 PM   #3
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Quote:
Originally Posted by somer View Post
Which is better remains to be seen, I like many here remain skeptical of the ZF8 transmission but from everything that I have read it's set to be the best iteration of the transmission yet. lemetier has assured us that we will not be let down with how it operates. From what I can gather, the best iteration of this transmission currently is in the Alfa gulia QV and I've watched many reviews and specifically their nurburgring lap to see how it reacts to paddle inputs and it does seem very responsive. Frankly I could count on one hand the amount of times I've been in auto mode in the M5, I don't see just because it has a ZF8 i would not use the paddles.

Alfa claims 150ms for their ZF8 shift program however @lemetier said this in the main thread "Indeed no argument. F10 M DCT was 80ms at its fastest. The F90 has cut that by more than 1/3."

Here is the lap of the QV, pay attention to the paddles. The QV also has the exact same gear ratios and a 7k rpm redline so the shift points will be near identical.

Naturally, there will be some who will claim it?s not as engaging simply because of expectation bias. The F90 transmission incorporates the new central processing unit just like the ZF 8DT which really makes this a very versatile gear box. Think of it as a planetary dual clutch with a low speed comfort torque converter. When you want fast and aggressive shifts, the TC is locked at 7km/h - 3 ft of movement. From there, only the dual internal shift clutches are responsible for the shifts. When you?re in traffic, the TC is more active to smooth things out and eliminate clutch wear.

The Giulia Is the 100ms variant in the most aggressive setting. The Alpina B7 is 80ms.
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      10-13-2017, 11:28 PM   #4
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What makes me wonder is how is this transmission compared to a DCT is the fact that a DCT pre engages the next gear for super fast shifts, I don't think that this transmission can ever match the speed of the DCT then right?
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      10-14-2017, 03:26 AM   #5
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Quote:
Originally Posted by Snappy Phoenix View Post
What makes me wonder is how is this transmission compared to a DCT is the fact that a DCT pre engages the next gear for super fast shifts, I don't think that this transmission can ever match the speed of the DCT then right?
Not necessarily. Here is a detailed description of how the ZF 8HP works, and in particular:

Quote:
All sequential upshifts and downshifts with this design involve just releasing one shift element and engaging another. In engineering literature, this is referred to as a “clutch to clutch” shift. Many skip shifts are also possible in the same way, e.g. a shift from Eighth to Fourth involves releasing brake A and engaging brake B while leaving clutches D and E engaged. This transmission therefore shifts very quickly. If the torque converter is replaced by a launch clutch, this transmission would be equivalent to a dual clutch transmission.
This, coupled with the fact that lemetier has said that the TC is locked at above 7 kph, indicates that the system behaves very much like a DCT under most circumstances when in the most aggressive shift mode.
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      10-14-2017, 06:42 AM   #6
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Quote:
Originally Posted by Snappy Phoenix View Post
What makes me wonder is how is this transmission compared to a DCT is the fact that a DCT pre engages the next gear for super fast shifts, I don't think that this transmission can ever match the speed of the DCT then right?
It does the same thing. There are two internal ?clutches? - Brake Set A and B, which act like the DCT clutch pack. When the TC is mechanically locked, what you end up with is a planetary dual clutch.
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      10-14-2017, 10:29 AM   #7
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Quote:
Originally Posted by lemetier View Post
It does the same thing. There are two internal ?clutches? - Brake Set A and B, which act like the DCT clutch pack. When the TC is mechanically locked, what you end up with is a planetary dual clutch.
So how do those heat-sensing paddles play a part in shift times/response, etc?
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      10-14-2017, 07:37 PM   #8
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Quote:
Originally Posted by Snappy Phoenix View Post
So now that the M5 has an Auto transmission vs the previous DCT. But it still has paddle shifters so my question is which is better? Would the auto with paddle shifters shift as fast as a DCT with paddle shifters? or does it shine when in auto mode only and the paddle shifters are just there if you want more fun and control?
The main issue with ZF8 is not the shift speed.... it's that creepy feeling of torque converter when you release the gas pedal even on low slope uphills...
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      10-14-2017, 08:28 PM   #9
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Quote:
Originally Posted by M6-Coupe View Post
Quote:
Originally Posted by Snappy Phoenix View Post
So now that the M5 has an Auto transmission vs the previous DCT. But it still has paddle shifters so my question is which is better? Would the auto with paddle shifters shift as fast as a DCT with paddle shifters? or does it shine when in auto mode only and the paddle shifters are just there if you want more fun and control?
The main issue with ZF8 is not the shift speed.... it's that creepy feeling of torque converter when you release the gas pedal even on low slope uphills...
It doesn?t have creep. It will roll backwards a bit.
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      10-14-2017, 08:30 PM   #10
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Quote:
Originally Posted by somer View Post
Quote:
Originally Posted by lemetier View Post
It does the same thing. There are two internal ?clutches? - Brake Set A and B, which act like the DCT clutch pack. When the TC is mechanically locked, what you end up with is a planetary dual clutch.
So how do those heat-sensing paddles play a part in shift times/response, etc?
By providing additional information to better predict the drivers intention to perform a stepped shift. At redline the pendulum can over speed the gear box if you abruptly let off the throttle almost simultaneously but slightly later, pull the paddle.
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      10-27-2017, 10:30 PM   #11
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My main issue with the ZF8, after having it in my 535i and my 435i, compared to my E92 M3 with the DCT is the fact that I can't shift the transmission in first gear at redline as it bogged 1k-1.5k RPM before redline. This bogging truly took away from the experience and ever since moving to the DCT I haven't bounced off redline in any gear due to computer limitations.

Also, this may be personal preference, I like how much more aggresively the DCT downshifts compared to the ZF8

The early shifting can be seen in this video:
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      10-30-2017, 11:20 AM   #12
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Quote:
Originally Posted by Lt1camaro View Post
My main issue with the ZF8, after having it in my 535i and my 435i, compared to my E92 M3 with the DCT is the fact that I can't shift the transmission in first gear at redline as it bogged 1k-1.5k RPM before redline. This bogging truly took away from the experience and ever since moving to the DCT I haven't bounced off redline in any gear due to computer limitations.

Also, this may be personal preference, I like how much more aggresively the DCT downshifts compared to the ZF8

The early shifting can be seen in this video:
oh darn that's a bummer. So you're not in full control even if you're in manual mode like it is with the DCT
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      11-02-2017, 05:53 PM   #13
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Quote:
Originally Posted by Lt1camaro View Post
My main issue with the ZF8, after having it in my 535i and my 435i, compared to my E92 M3 with the DCT is the fact that I can't shift the transmission in first gear at redline as it bogged 1k-1.5k RPM before redline. This bogging truly took away from the experience and ever since moving to the DCT I haven't bounced off redline in any gear due to computer limitations.

Also, this may be personal preference, I like how much more aggresively the DCT downshifts compared to the ZF8

The early shifting can be seen in this video:
It's not the same 8HP in either car you mention. In the F90, it will shift at redline in auto and will NOT upshift at redline in manual (stepped) mode.

I have driven the car and with the most aggressive settings and manual shift mode active, it's very much reminiscent of SMG III in its voracity and a touch faster than M-DCT in speed.
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      11-02-2017, 05:55 PM   #14
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Quote:
Originally Posted by Snappy Phoenix View Post
Quote:
Originally Posted by Lt1camaro View Post
My main issue with the ZF8, after having it in my 535i and my 435i, compared to my E92 M3 with the DCT is the fact that I can't shift the transmission in first gear at redline as it bogged 1k-1.5k RPM before redline. This bogging truly took away from the experience and ever since moving to the DCT I haven't bounced off redline in any gear due to computer limitations.

Also, this may be personal preference, I like how much more aggresively the DCT downshifts compared to the ZF8

The early shifting can be seen in this video:
oh darn that's a bummer. So you're not in full control even if you're in manual mode like it is with the DCT
Read my response.

To add, this is honestly the first Automatic that is smarter than the driver. When equipped with all the Driver Assistant options and Adaptive Cruise Control, the car is capable of complete 10/10 autonomous laps without skipping a beat. Unfortunately this won't be fully enabled on customer cars, but a significant portion will be.
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      11-02-2017, 08:08 PM   #15
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And to add, I've spent the past few weeks driving every "Automatic" performance gearbox available back to back and this is my personal preference from best to worst of the more common ones:

ZF 7DT PDK-S (991.2 Turbo S Exclusive)
ZF 8HPtu2 (F90 M5)
ZF 8DT PDK Sport Chrono (Panamera Turbo Sport Turismo)
ZF 8HPtu (G12 - Alpina B7)
ZF 7DT Sport Chrono (991.2 Turbo Cab)
Getrag/Borg Warner DCI750 (M-DCT F80 M3"CS" Mule)
MB 9G-MCT (E63S Wagon)
ZF 8HPtu (M760i)
MB 7G-Tronic Speed-shift (G63)

Burn it with fire...

MB 7G-MCT (C63S)
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      11-02-2017, 10:12 PM   #16
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Extremely informative as always, thank you. Have you had any look at Competition Package wheels yet? Hoping they're markedly better than the 706M's.
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      11-02-2017, 10:21 PM   #17
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Quote:
Originally Posted by somer View Post
Extremely informative as always, thank you. Have you had any look at Competition Package wheels yet? Hoping they're markedly better than the 706M's.
They're a mesh spoke style (10 iirc) with an additional M Performance 5 Y Spoke is coming as well.

The Competition Package should be separate from the Track Package on offer already in RoW markets.
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      11-02-2017, 10:29 PM   #18
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Quote:
Originally Posted by lemetier View Post
They're a mesh spoke style (10 iirc) with an additional M Performance 5 Y Spoke is coming as well.

The Competition Package should be separate from the Track Package on offer already in RoW markets.
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      11-02-2017, 10:46 PM   #19
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Quote:
Originally Posted by somer View Post
Quote:
Originally Posted by lemetier View Post
They're a mesh spoke style (10 iirc) with an additional M Performance 5 Y Spoke is coming as well.

The Competition Package should be separate from the Track Package on offer already in RoW markets.
A little inspiration for the mind...
Attached Images
 
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      11-03-2017, 10:47 AM   #20
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Originally Posted by lemetier View Post
A little inspiration for the mind...
Is that going to be the Competition Package Wheel design?!
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      11-03-2017, 10:55 AM   #21
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Exclamation

Quote:
Originally Posted by lemetier View Post
A little inspiration for the mind...

Do you know when the competition package will be available? should I wait?
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      11-03-2017, 01:46 PM   #22
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Quote:
Originally Posted by M.S.B View Post
Quote:
Originally Posted by lemetier View Post
A little inspiration for the mind...

Do you know when the competition package will be available? should I wait?
Summer of 2018.
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