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      11-22-2012, 01:47 PM   #1
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DCT tranny

if they put a double clutch transmission in im going to buy this car. right now im stuck between the manual and auto transmission.

i love stick but others in the family cant drive manual.

i know ill miss the stick so i would compromise with a DCT tranny.

anyone else have this manual / auto dilemma?
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      11-22-2012, 01:53 PM   #2
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the ZF8 sport is just as quick as a DCT. I have driven both audi and BMW dct's, the ZF8 is just as good
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      11-22-2012, 02:06 PM   #3
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I had the DCT in my M3. The 8AT is good, but it's not the same. The ZF 8AT is perfectly suited for all f30s, however.
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      11-22-2012, 02:59 PM   #4
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I cross shopped with the S4 and found the DCT fantastically quick, but the shift maps seemed "off". If you opened it up but then let off the transmission would get all confused and start jerking you around. OTOH the 8 speed sport auto was incredibly smooth in sport mode really no matter what you are doing.

edit: of course this is more directed at the VAG 7sp shiftronic rather than DCT...

Not sure if this matters, but I've read servicing DCT can be a nightmare if something goes wrong, not to say that the 8 speed would be any different.
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      11-22-2012, 03:05 PM   #5
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Quote:
Originally Posted by SamS View Post
I had the DCT in my M3. The 8AT is good, but it's not the same. The ZF 8AT is perfectly suited for all f30s, however.
I miss being able to roll back on an incline with my z4 SMG =\

It was terrible in traffic though, same goes for the DCT imo (although not nearly as much).
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      11-22-2012, 11:28 PM   #6
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Quote:
Originally Posted by justinnum1
the ZF8 sport is just as quick as a DCT. I have driven both audi and BMW dct's, the ZF8 is just as good
Soo true! I have used both a DCT and the ZF 8 speed auto and i still love the ZF.. Its just ridiculously fast, but smooth when you need it to be. The clutch movements when in tight traffic are a pain on the behind in the DCT
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      11-22-2012, 11:59 PM   #7
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Quote:
Originally Posted by 949 View Post
if they put a double clutch transmission in im going to buy this car. right now im stuck between the manual and auto transmission.

i love stick but others in the family cant drive manual.

i know ill miss the stick so i would compromise with a DCT tranny.

anyone else have this manual / auto dilemma?
Edited for corrections:

Yes, I too had this decision.
I'm an MT driver at heart, but after reading up on the ZF sport AT and then trying it out, I was sold on trying it.

I've not tried a BMW DCT, but I've tried many Audi DSG's and the one in the S4. The S4's is a very nice and quick trans.
But the ZF is it's equal in speed. The ZF's advantage is that it's smoother due to having a torque converter.
Plus, the ZF can do multi gear downshifts and skip gears whereas the dual clutch trannies can't do it as quickly not. In the ZF if you go from 6th to 3rd it will only need to do one shift and you're in 3rd. The dual clutch needs to shift between odd and even gear shafts, so depending on which gear you are in it may take 1 or 2 shifts to get the lower gear you want.
The ZF feels faster on downshift because it can skip straight through to the lower gear.
Upshifts are just as fast with the sport ZF as dual clutches at 200 milliseconds per shift.
Fastest shifts are done when in sport drivers mode or DS trans mode.
Smoothest shifts are in comfort mode and D/auto sport mode.
Manual mode is also just as quick.

After driving mine for 3K miles I find the sport AT very satisfying, smooth when I want it, and fast when I want it.
But, it does not give me the same feel and driving experience as an MT, and it can't simply because there is a different mode of operation between an AT and MT. With MT you do the shifting and clutch work and you decide when to up or downshift. Even in manual mode with the AT it's not the same feel as there is no clutch to be used.

Will I ever go back to MT? Yes. Not because the sport AT sucks, just because I may want to go back to moving levers and engaging the clutch.
It's a different feel that's all.
The ZF AT is fantastic and I'm glad I choose it as I wanted to try out the BEST AT in the market. And now I know, and I can judge the differences between MT and this type of AT much better than before.

I need to take my 335i in to the shop though, as it feels like the rev matching downshifts aren't as smooth as they were when new.
Could be a programming thing, but maybe it's mechanical and the fluid level is not correct.

Last edited by RPM90; 11-23-2012 at 03:45 AM.
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      11-23-2012, 12:06 AM   #8
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Quote:
Originally Posted by RPM90 View Post
Plus, the ZF can do multi gear downshifts and skip gears whereas the dual clutch trannies can not. In the ZF if you go from 6th to 3rd it will only need to do one shift and you're in 3rd. The dual clutch needs to shift down each gear even though it does it very fast. The ZF feels faster on downshift because it can skip.
Upshifts are just as fast with the sport ZF as dual clutches, and that's per ZF who also make the DCT.

This is simply untrue. BMW DCT can downshift without going through each gear. You give it judicious acceleration, and hold the downshift lever. It can go directly from 7th to 4th, no problem.
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      11-23-2012, 02:11 AM   #9
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F30 ZF-8AT indeed is incredible smooth and very power/fuel efficiŽnt. Was immediately sold upon announcement. 15K Miles still convinced...... above expectations...
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      11-23-2012, 04:11 AM   #10
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I own a 135i 7DCT as well as an F30 335i 8AT and an Audi A3 6DSG. Considering I'm an actual track whore and not a magazine racer I will tell you that the 8AT is indeed smooth and downshifts quickly into the meat of the powerband where the 7DCT hesitates a bit before dumping down...but the 8AT technically loses out to both Dual Clutch Gearboxes in pure upshift speed. On the track the DCT is quite the thing when shifting manually and the 8AT feels a little less immediate but in real world driving applications it is almost negligible and the 8AT's 300ms shift speed is unbelievably fast for a torque converted tranny while the 200ms-60ms range of the getrag DCT unit is technically faster but not quite as smooth at speed. Ultimately it's quite inconsequential and I think ZF has done an amazing job with the unit and bmw, as well, with their programming of it. There's a reason there are several car manufacturers using it now.

NOTE: a post above notes that the DCT cannot disengage to skip downshifts...this is entirely untrue. It can go from 7-4 in a jiffy without needing to go down each gear.
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      11-23-2012, 04:37 AM   #11
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I've had the Z4 35is DCT and now have the F30 8AT, the DCT in the Z4 is much more 'agressive' than the 8AT (when put into sport/sport+) ....
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      11-23-2012, 04:53 AM   #12
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Quote:
Originally Posted by SamS View Post
This is simply untrue. BMW DCT can downshift without going through each gear. You give it judicious acceleration, and hold the downshift lever. It can go directly from 7th to 4th, no problem.
Yes it can. I shouldn't have said it can't.
I should have the point I was trying to make better, correctly.
I corrected that post to not leave incorrect info.
Also, Getrag makes the DCT not ZF. DOH!
ZF makes the dual clutch for Porsche.

A dual clutch can skip gears on downshift, but it can't skip like the ZF does, directly to the gear requested, depending on the gear it's in and the gear called for.
I've posted before on this forum about how the ZF AT works after researching it quite a bit.
That info comes from ZF info and other tech sources.

The reason why a dual clutch can't downshift as directly is because of how a dual clutch is made, using 2 shafts, one for even number gears and one for odd.
Lets say we're in 6th gear and you call up 4th, the first gear change is going to be to 5th on the opposite odd number shaft. It can't go directly to 4th because 4th is on the same shaft as 6th. Once in 5th, then the even number shaft can select 4th and engage. That's 2 shifts, and it's very fast.
If you're in 6th and call up 2nd, the dual clutch may be able to go to 5th first and then select 2nd on the even number shaft.
Although I'm not positive that it will do that.
If it does, then it's still just 2 shifts. If not, then it's more.

With the ZF AT in 6th and you call up 4th, it can go directly to 4th, one shift.

Upshifts are 200 milliseconds for a single shift, but downshifts can be as fast as 100 milliseconds.
If you have the AT give it a try, it's very cool. But, you have to be fast on the lever or the paddles.

ZF 8spd info:
Company product development director Dr Klaus Draeger explained that the eight-speed ZF is now able to shift as fast as a good DCT and, he told DCTFacts.com, offered other advantages too.

"If you want to shift quickly from 6th to 4th, or from 7th to 5th, you can do this in a single step with the eight-speed. On the DCT it takes longer as the shifts are sequential."

Sportier versions of the eight-speed will also be introduced, said Draeger, but he declined to say whether they would use a wet clutch launch device, as on the AMG Speedshift, which allows sharper shifts and higher engine revolutions.

"The torque converter is an excellent launch device," said Draeger. "It has many advantages: we close it out at just 1000 rpm, when the car has traveled only 2 to 3 meters from rest, so it's almost never involved. And besides, its performance stays exactly the same throughout the whole lifetime of the vehicle - we don't ever get warranty claims on torque converters."


This is from ZF and Alpina:
The SWITCH-TRONIC buttons, for use in the Manual (M) Shift Mode, are ergonomically and unobtrusively positioned on the
back of the steering wheel, and allow the driver to take complete control of the transmission. The system allows for multisimultaneous down-shifts in milliseconds, hereby the transmission will skip several gears depending on engine loads and
rpm. In this manner the 8-speed Sport Automatic Transmission with ALPINA SWITCH-TRONIC reveals itself as extremely
multi-faceted, providing the right shift characteristic for any and all situations.


This also from ZF:
Those who appreciate
agility will be happy to know that the most modern
adaptive shift strategies are used which enable
direct skip-shifts over multiple gears, even allowing
for extreme downshifts such as 8th gear to 2nd gear.
In spite of the dry facts, maximum driving pleasure
is guaranted.

Last edited by RPM90; 11-23-2012 at 04:58 AM.
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      11-23-2012, 10:20 AM   #13
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The 2013 $200,000 Bentley GT also has the 8 speed ZF transmission so that shows just how good the 8 speed auto is in the F30.


http://www.roadandtrack.com/future-c...ental-gt-speed
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      11-23-2012, 03:39 PM   #14
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I was coming from 10 years of driving manuals, as well as VW DSG gearboxes in the wife's car, and I am completely thrilled with the 8AT performance.

It's unbelievably smooth, it shifts faster than anyone with a clutch can (I don't know why everyone is stuck up on the DCT vs AT argument in this thread, the real answer is the 8AT is faster than a manual).

I drove a lot of cars before giving up my clutch, and theres times when I still miss throwing a good heel toe onto an off ramp, but other than that the smoothness, directness and speed of the 8AT is better than any other automatic I've ever driven.
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      11-23-2012, 04:22 PM   #15
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I love the MT.
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      11-24-2012, 06:41 AM   #16
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The ZF 8AT is the best gearbox ever made IMO
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      11-24-2012, 07:10 AM   #17
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Quote:
Originally Posted by MaestroAl View Post
The ZF 8AT is the best gearbox ever made.
Assuming this opinion is even close to true, the ZF is the stuff to get. People who like to push the pedal and wiggle the stick can choose to do so but for me the bloom came off that one years ago. I just want a performing tranny and ordered the sport automatic. Loved it in the test drive...
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      11-24-2012, 08:03 AM   #18
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I don't remember. Is the ZF or Sport Auto tranny a cost-adder? I remember when I got my prior cars, the MT was a savings but when I ordered this latest car, there was no savings getting the MT. But I don't recall what was "standard" with the car....a ZF or DCT.
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      11-24-2012, 10:29 AM   #19
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Quote:
Originally Posted by RPM90 View Post
Yes it can. I shouldn't have said it can't.
I should have the point I was trying to make better, correctly.
I corrected that post to not leave incorrect info.
Also, Getrag makes the DCT not ZF. DOH!
ZF makes the dual clutch for Porsche.

A dual clutch can skip gears on downshift, but it can't skip like the ZF does, directly to the gear requested, depending on the gear it's in and the gear called for.
I've posted before on this forum about how the ZF AT works after researching it quite a bit.
That info comes from ZF info and other tech sources.

The reason why a dual clutch can't downshift as directly is because of how a dual clutch is made, using 2 shafts, one for even number gears and one for odd.
Lets say we're in 6th gear and you call up 4th, the first gear change is going to be to 5th on the opposite odd number shaft. It can't go directly to 4th because 4th is on the same shaft as 6th. Once in 5th, then the even number shaft can select 4th and engage. That's 2 shifts, and it's very fast.
If you're in 6th and call up 2nd, the dual clutch may be able to go to 5th first and then select 2nd on the even number shaft.
Although I'm not positive that it will do that.
If it does, then it's still just 2 shifts. If not, then it's more.

With the ZF AT in 6th and you call up 4th, it can go directly to 4th, one shift.

Upshifts are 200 milliseconds for a single shift, but downshifts can be as fast as 100 milliseconds.
If you have the AT give it a try, it's very cool. But, you have to be fast on the lever or the paddles.

ZF 8spd info:
Company product development director Dr Klaus Draeger explained that the eight-speed ZF is now able to shift as fast as a good DCT and, he told DCTFacts.com, offered other advantages too.

"If you want to shift quickly from 6th to 4th, or from 7th to 5th, you can do this in a single step with the eight-speed. On the DCT it takes longer as the shifts are sequential."

Sportier versions of the eight-speed will also be introduced, said Draeger, but he declined to say whether they would use a wet clutch launch device, as on the AMG Speedshift, which allows sharper shifts and higher engine revolutions.

"The torque converter is an excellent launch device," said Draeger. "It has many advantages: we close it out at just 1000 rpm, when the car has traveled only 2 to 3 meters from rest, so it's almost never involved. And besides, its performance stays exactly the same throughout the whole lifetime of the vehicle - we don't ever get warranty claims on torque converters."


This is from ZF and Alpina:
The SWITCH-TRONIC buttons, for use in the Manual (M) Shift Mode, are ergonomically and unobtrusively positioned on the
back of the steering wheel, and allow the driver to take complete control of the transmission. The system allows for multisimultaneous down-shifts in milliseconds, hereby the transmission will skip several gears depending on engine loads and
rpm. In this manner the 8-speed Sport Automatic Transmission with ALPINA SWITCH-TRONIC reveals itself as extremely
multi-faceted, providing the right shift characteristic for any and all situations.


This also from ZF:
Those who appreciate
agility will be happy to know that the most modern
adaptive shift strategies are used which enable
direct skip-shifts over multiple gears, even allowing
for extreme downshifts such as 8th gear to 2nd gear.
In spite of the dry facts, maximum driving pleasure
is guaranted.
RPM90

You make a big deal about being able to skip gears on a downshift, and I don't refute your information on what gearboxes can and can't.

The question I have is why? Why would you need to downshift 3-4 gears in an instant unless you had fallen asleep at the wheel?

I have driven large braked, sticky tyred M3's on track (DCT versions), stamping on the brakes at the end of the straight going from 6th to a 2nd gear corner, and have never thought 'Jeez this gearbox needs to change down quicker'
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      11-24-2012, 12:31 PM   #20
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Quote:
Originally Posted by NISFAN View Post
RPM90

You make a big deal about being able to skip gears on a downshift, and I don't refute your information on what gearboxes can and can't.

The question I have is why? Why would you need to downshift 3-4 gears in an instant unless you had fallen asleep at the wheel?

I have driven large braked, sticky tyred M3's on track (DCT versions), stamping on the brakes at the end of the straight going from 6th to a 2nd gear corner, and have never thought 'Jeez this gearbox needs to change down quicker'
+1, including the track experience with a DCT. In fact, I have never been caught out of gear with an old fashioned 6-speed manual on the track.

Additionally, while the ZF marketing literature states the AT can downshift from eight to two directly, I have yet to read or experience anything that demonstrates this is the case in the F30 implementation. (The control software is modified for each vehicle model in which the tranny is installed for engine characteristics, rear drive ratio, weight, mileage considerations, etc.)
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      11-24-2012, 12:52 PM   #21
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From 8th, the 8HP can shift directly into 2nd, 4th, or 6th. I assume it has more to do with needing to rapidly accelerate while cruising at city or highway speeds, rather than downshifting for a corner during a track session.

http://www.zf.com/media/media/img_1/...Produkt_EN.PDF
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      11-24-2012, 03:11 PM   #22
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Yes, we know what the marketing literature states. But is there anything that demonstrates the ZF can/will do a direct eight to two shift as installed in an F30?
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