BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > M3 (E90 / E92 / E93) > General M3 Forum (E90 + E92 + E93)
 
Post Reply
 
Thread Tools Search this Thread
      10-24-2007, 02:18 AM   #1
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,201
iTrader: (1)

M-DCT "preview" (by way of Mitsubishi)

We can get some very valuable insight into what may likely lie in store for us with BMWs M-DCT dual clutch automated manual transmission by examining the new Evo X TC-SST (Twin Clutch-Sportronic Shift Transmission). Wow what a name, have to say I prefer simply "dual clutch transmission".

This is an optional transmission which is offered in addition to the standard 5 speed MT. It provides both automatic modes as well as a paddle shifted manual mode (almost for sure shiftable via the stick on the transmission tunnel as well - any Evo fans want to confirm that?). It's three automatic modes are Normal, Sport and S-Sport. Normal is for everyday cruising, Sport is meant for more spirited driving wheras S-Sport is for full on track use. According to Road&Track, S-Sport is far more aggressive than the sportiest VW/Audi DSG setting (again like I have been saying all along - software will be as important as the mechanical design for M-DCT as this is the only difference between the various automatic modes - software). In S-Sport mode, again a fully automatic mode, upshifts only occur at redline and downshifts occur automatically on slowing for corners. Also, according to R&T, the TC-SST system, "worked flawlessley in both manual and automatic modes" around the 2 mile Mitsubishi test track. In fact the R&T driver said that on this track the TC-SST shifted exactly where he would have if he was shifting a MT. The transmission was simply "fantastic". The only noted problem on this pre-production unit was trouble getting ideal launches (echos of BMWs SMG...). The Evo Chief Engineer insisted that this small remaining detail would be fully addressed before the production models with this transmission are released.

Last but not least, despite the new Evo X feeling slower and less edgy than the outgoing Evo IX model (it is in fact a tad slower than the outgoing IX 0-60), with TC-SST in S-Sport mode the Evo X bests the IX around this same 2 mile track by about 1 second! Some of this gain should also be attributed to the AYC (active yaw control system) which is basically an actively controlled rear differential to reduce both under and over steer. However the extra 300 lb of the X over the IX and worse power to weight ratio (11.3 lb/hp for the X vs 10.7 for the IX) is not in favor of the X achieving a better time either, so indeed AYC and TC-SST are really doing something here! Just FYI: 1 second in 2 miles would translate to about 6 seconds on the Nurburgring if the average speeds and gains scale solely on the distance of the track. Hmmm what were my personal estimates of the gains that M-DCT will show on the Ring...

Can you hear some of the same things we know about the E92 M3 vs. the outgoing M3 in this information (less edgy but a better performer)? I am confident that BMW will match or exceed Mitsubishi's excellent TC-SST with their M-DCT. If only it will get to the US simultaneously with the cars launch. Us M-DCT fans can only hope...and pray.
swamp2 is offline   United_States
0
Reply With Quote
      10-24-2007, 02:51 AM   #2
Sedan_Clan
Banned
 
Drives: '14 335i(prev.IB,AW M3's & X5)
Join Date: Jun 2006
Location: On 2 wheels clipping an apex!

Posts: 10,921
iTrader: (25)

I read about this in the new Motor Trend. Pretty sophisticated stuff........

...but I'll stick w/ my traditional manual still.
Sedan_Clan is offline   Brazil
0
Reply With Quote
      10-24-2007, 05:44 AM   #3
mkoesel
Moderator
 
Drives: 2015 SO/CSAT F80 M3
Join Date: Jun 2006
Location: Canton, MI

Posts: 13,751
iTrader: (1)

Thanks swamp. I'll probably go google this now, but I wonder - what about the manual modes?
__________________
A gen-u-ine BMW eff-eight-zero with them tandem clutches in the transmission and that dad gum sun roof on the top-a da cawr.
mkoesel is online now   United_States
0
Reply With Quote
      10-24-2007, 06:18 AM   #4
Epacy
Reincarnated
 
Epacy's Avatar
 
Drives: 02 Maxima SE
Join Date: Mar 2007
Location: IL

Posts: 4,227
iTrader: (0)

Garage List
2008 M3  [0.00]
Quote:
Originally Posted by Sedan_Clan View Post
I read about this in the new Motor Trend. Pretty sophisticated stuff........

...but I'll stick w/ my traditional manual still.
Ditto. Thought of posting this here, but really only Swamp would gush over it.
__________________
Epacy is offline  
0
Reply With Quote
      10-24-2007, 08:13 AM   #5
ILC32
Lieutenant
 
ILC32's Avatar
 
Drives: 1993 Porsche RSA
Join Date: Aug 2005
Location: Somewhere

Posts: 580
iTrader: (0)

I definitely will not get the car untill DSG or SMG is available. I have no issues with SMG in my E46 M3, so even if DSG cannot be implemented in the M3 for whatever reason (perhaps too much hp or tq for current technology?), I would still be very happy with SMG.
ILC32 is offline  
0
Reply With Quote
      10-24-2007, 08:23 AM   #6
Epacy
Reincarnated
 
Epacy's Avatar
 
Drives: 02 Maxima SE
Join Date: Mar 2007
Location: IL

Posts: 4,227
iTrader: (0)

Garage List
2008 M3  [0.00]
Quote:
Originally Posted by ILC32 View Post
... even if DSG cannot be implemented in the M3 for whatever reason (perhaps too much hp or tq for current technology...
I doubt this will be a problem.
__________________
Epacy is offline  
0
Reply With Quote
      10-24-2007, 09:08 AM   #7
03SG///M3
Lieutenant
 
Drives: 328
Join Date: Jan 2006
Location: CT

Posts: 579
iTrader: (0)

Quote:
Originally Posted by ILC32 View Post
I definitely will not get the car untill DSG or SMG is available. I have no issues with SMG in my E46 M3, so even if DSG cannot be implemented in the M3 for whatever reason (perhaps too much hp or tq for current technology?), I would still be very happy with SMG.
I second that... I would be more than fine with an SMG transmission in the E92 M3.
03SG///M3 is offline  
0
Reply With Quote
      10-24-2007, 10:06 AM   #8
GregW / Oregon
Commander-In-Chief
 
Drives: 2015 M4 Coupe, 2012 ML350
Join Date: Nov 2005
Location: Lake Oswego, OR

Posts: 7,569
iTrader: (2)

Garage List
DSG

Quote:
Originally Posted by ILC32 View Post
...so even if DSG cannot be implemented in the M3 for whatever reason (perhaps too much hp or tq for current technology?), I would still be very happy with SMG.
The Getrag unit rumored for the M3 has more than enough capacity. Check out the specs...



KEY BENEFITS

- Optimized efficiency
- Shifting without interruption of traction
- Excellent comfort
- Very quick and sportive shiftings possible

KEY FEATURES
-Max. Torque Capacity 600 Nm
-Weight (dry) 79 kg
-Installation length 660 mm
-Synchronization:
1st, 2nd and 3th gear dual cone
4th and 5th gear single cone
6th, and 7th gear dual cone
Reverse gear single cone

- Gear Spread Ratio 6,8
- Max. Gross Vehicle Mass/Gross Trailer Mass 2500 kg/4500 kg
- Shifter System hydraulic

http://www.getrag.de/455
__________________

Greg Lake Oswego, Oregon, USA
2015 M4 Coupe - Silverstone/Sakhir/CF
2012 ML350
GregW / Oregon is offline   United_States
0
Reply With Quote
      10-24-2007, 10:08 AM   #9
GregW / Oregon
Commander-In-Chief
 
Drives: 2015 M4 Coupe, 2012 ML350
Join Date: Nov 2005
Location: Lake Oswego, OR

Posts: 7,569
iTrader: (2)

Garage List
TSG?

I think what is really needed is a TCT (Triple Clutch Transmission) so that one higher and one lower gear can always be preselected!
__________________

Greg Lake Oswego, Oregon, USA
2015 M4 Coupe - Silverstone/Sakhir/CF
2012 ML350

Last edited by GregW / Oregon; 10-24-2007 at 10:33 AM.
GregW / Oregon is offline   United_States
0
Reply With Quote
      10-24-2007, 10:24 AM   #10
TTBear
Lieutenant
 
TTBear's Avatar
 
Drives: '09 LP560, '14 M235i, '12 X6M
Join Date: Apr 2007
Location: Canada

Posts: 558
iTrader: (4)

This is what I don't understand about the DSG transmissions. Say you are on track, acclerating in third gear, and the tranny has preselected fourth. Instead of continuing to accelerate, you approach a corner, and thus want to DOWNSHIFT into second. Won't the shift be really slow, as it has to disengage fourth, and then engage second?

Or am I missing something here?
TTBear is offline   Canada
0
Reply With Quote
      10-24-2007, 10:35 AM   #11
GregW / Oregon
Commander-In-Chief
 
Drives: 2015 M4 Coupe, 2012 ML350
Join Date: Nov 2005
Location: Lake Oswego, OR

Posts: 7,569
iTrader: (2)

Garage List
DCT shifts

Quote:
Originally Posted by TTBear View Post
This is what I don't understand about the DSG transmissions. Say you are on track, acclerating in third gear, and the tranny has preselected fourth. Instead of continuing to accelerate, you approach a corner, and thus want to DOWNSHIFT into second. Won't the shift be really slow, as it has to disengage fourth, and then engage second?

Or am I missing something here?
It will be slower, the reason for my post above.
__________________

Greg Lake Oswego, Oregon, USA
2015 M4 Coupe - Silverstone/Sakhir/CF
2012 ML350
GregW / Oregon is offline   United_States
0
Reply With Quote
      10-24-2007, 10:45 AM   #12
mkoesel
Moderator
 
Drives: 2015 SO/CSAT F80 M3
Join Date: Jun 2006
Location: Canton, MI

Posts: 13,751
iTrader: (1)

Quote:
Originally Posted by GregW / Oregon View Post
I think what is really needed is a TCT (Triple Clutch Transmission) so that one higher and one lower gear can always be preselected!
Actually the ideal would be one clutch per gear, so that it doesn't have to shift sequentially.

Of course, that would weigh a ton.
__________________
A gen-u-ine BMW eff-eight-zero with them tandem clutches in the transmission and that dad gum sun roof on the top-a da cawr.
mkoesel is online now   United_States
0
Reply With Quote
      10-24-2007, 11:19 AM   #13
aerisolphaln
First Lieutenant
 
Drives: '05 G35 coupe 6MT
Join Date: Dec 2006
Location: Iowa City, IA

Posts: 396
iTrader: (0)

Quote:
Originally Posted by TTBear View Post
This is what I don't understand about the DSG transmissions. Say you are on track, acclerating in third gear, and the tranny has preselected fourth. Instead of continuing to accelerate, you approach a corner, and thus want to DOWNSHIFT into second. Won't the shift be really slow, as it has to disengage fourth, and then engage second?

Or am I missing something here?
I would imagine the software would overcome this issue. So you're on the track in "ultra-sport" transmission mode in 3rd gear. I would bet that 2nd gear would be pre-selected by the transmission up until you reach RPM levels in 3rd gear that would no longer be compatible with a down shift into 2nd, at which point the pre-selected gear would become 4. This would happen at the RPM point in 3rd where the down shift to 2nd would be, say, within 500 of redline, making the downshift impractical. This would make the most sense to me.
__________________
Now:'05 G35 6MT\Laser Red\Beige\Sport\Premium

06/2008: M3, 335+Dinan, or ...
aerisolphaln is offline   United_States
0
Reply With Quote
      10-24-2007, 11:22 AM   #14
aerisolphaln
First Lieutenant
 
Drives: '05 G35 coupe 6MT
Join Date: Dec 2006
Location: Iowa City, IA

Posts: 396
iTrader: (0)

And I think that the slowest DCT shifts will be an order of magnitude quicker than the fastest professional human shifts.
__________________
Now:'05 G35 6MT\Laser Red\Beige\Sport\Premium

06/2008: M3, 335+Dinan, or ...
aerisolphaln is offline   United_States
0
Reply With Quote
      10-24-2007, 11:25 AM   #15
Sedan_Clan
Banned
 
Drives: '14 335i(prev.IB,AW M3's & X5)
Join Date: Jun 2006
Location: On 2 wheels clipping an apex!

Posts: 10,921
iTrader: (25)

I like simplicity. This transmission, be it installed in an EVO or the M3, is just another expensive part prone to problems (..and expensive repairs after warranty).
Sedan_Clan is offline   Brazil
0
Reply With Quote
      10-24-2007, 12:27 PM   #16
03SG///M3
Lieutenant
 
Drives: 328
Join Date: Jan 2006
Location: CT

Posts: 579
iTrader: (0)

The aforementioned concerns stated above about the preselected gears when on the track is why i think i would prefer SMG 3.
03SG///M3 is offline  
0
Reply With Quote
      10-24-2007, 01:03 PM   #17
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,201
iTrader: (1)

Good discussion. Hold on for a long multi-part reply...

Quote:
Originally Posted by mkoesel View Post
Thanks swamp. I'll probably go google this now, but I wonder - what about the manual modes?
Manual modes should be fairly simple. It only shifts when you click the paddles, period. I think it is likely that there will only be one manual mode. Since shifts always combine smoothness and lightning fast speeds why offer a range between slow/comfortable and fast/harsh?

Quote:
Originally Posted by Celsius View Post
Actually, I think Nissan's Dual Clutch system in the GTR might be better, but I don't think the published shift times reflect it?
There are no published shift times for BMWs nor Nissans systems AFAIK. Also we have most sources claiming 8 ms for DSG and one very credible source claiming 20-30 ms.

Quote:
Originally Posted by aerisolphaln View Post
I would imagine the software would overcome this issue. So you're on the track in "ultra-sport" transmission mode in 3rd gear. I would bet that 2nd gear would be pre-selected by the transmission up until you reach RPM levels in 3rd gear that would no longer be compatible with a down shift into 2nd, at which point the pre-selected gear would become 4. This would happen at the RPM point in 3rd where the down shift to 2nd would be, say, within 500 of redline, making the downshift impractical. This would make the most sense to me.
That is quite clever and probable I'd say. Again with software, the sky is the limit, it is only about how good they can quantify what a drive wants to happpen when.

Quote:
Originally Posted by Sedan_Clan View Post
I like simplicity. This transmission, be it installed in an EVO or the M3, is just another expensive part prone to problems (..and expensive repairs after warranty).
Don't be a luddite. There are a few good reasons to not want an M-DCT but this doesn't cut it for me. Would you say that BMWs dual VANOS system or the engine control unit with multiple 32 bit CPUs capable of 200 million calculations per second are "too complex" or subject to too many expensive repairs after warranty? There are essential components of a modern performance car that are reliable for a large percentage of the lifetime of the car (if not its entire lifetime).

Quote:
Originally Posted by TTBear View Post
This is what I don't understand about the DSG transmissions. Say you are on track, acclerating in third gear, and the tranny has preselected fourth. Instead of continuing to accelerate, you approach a corner, and thus want to DOWNSHIFT into second. Won't the shift be really slow, as it has to disengage fourth, and then engage second?

Or am I missing something here?
2 gear downshifts will make things slower but they should only get as slow as still better than any human and about like a regular SMG system. Furthermore the system will be designed for ultimate performance on the twisties and track as opposed to freeway speed contests. When decelerating on a track you typically downshift a gear at a time - just click off the paddles until you have the gear you like. The tranny knows you are decelerating and will corrrectly preselect a lower gear rather than a higher gear. Each shift can be as fast as the best upshift here. If you want two instant downshifts from say 6-4 on the freeway, for a bit of a race, you may be able to confuse the system a bit. However, even in the worst case scenario the actual clutch movements and shift mechanism movements will still be lightning fast it is just a matter of the software orchestrating the shifts you request. So for the 6-4 when in 6 the system may have 7 preselected it will then have to select 5 instead before clutch operations. Once in 5 there is the question again as to what next gear will be preselected - back to 6 or down to 4. Once that is sorted by the computer the next shift will occur. If the system realized you also gave the car full throttle I can see it getting the preselects correctly (down instead of up) as long as there is no risk of over reving, which will be contoinuosly monitored.
swamp2 is offline   United_States
0
Reply With Quote
      10-24-2007, 01:23 PM   #18
Hans Delbruck
BMW & MB - friends in my garage
 
Hans Delbruck's Avatar
 
Drives: C63, 135i, 1959 BUICK
Join Date: May 2005
Location: Huntington Beach, CA

Posts: 1,285
iTrader: (0)

Did Sam Mitani do the test and write the article? If so, then he's a good driver, and I believe it.

Otherwise, the new Evo SST trans takes a car that is already way too easy to drive fast, and makes it even easier. No wonder it's easy for an intermediate-novice-weekend track guy to go faster in the auto mode.

What this means in my NSHO (not so humble opinion) ... we are going to see more Evo drivers getting in over their heads and driving above their skills on the track and the street with this car. This car makes anyone look like a hero. The new one is going to take "point and steer" to a new level of 'no skills required.' I have personally witnessed how dangerous this car can be in the hands of a novice.... when things go wrong, it gets ugly really quick. These cars are prone to dig in and roll. Especially when the noobie drivers think it's ok to test their off-road capability at a track day.

Evo rant off (for now!)
Hans Delbruck is offline   United_States
0
Reply With Quote
      10-24-2007, 01:25 PM   #19
mkoesel
Moderator
 
Drives: 2015 SO/CSAT F80 M3
Join Date: Jun 2006
Location: Canton, MI

Posts: 13,751
iTrader: (1)

Quote:
Originally Posted by swamp2 View Post
Manual modes should be fairly simple. It only shifts when you click the paddles, period. I think it is likely that there will only be one manual mode. Since shifts always combine smoothness and lightning fast speeds why offer a range between slow/comfortable and fast/harsh?
Well I don't know the answer to the last question, but from what I found when I googled there are three manual modes, just like there are three auto modes. However, I could not find a detailed explanation of the differences between them.

__________________
A gen-u-ine BMW eff-eight-zero with them tandem clutches in the transmission and that dad gum sun roof on the top-a da cawr.
mkoesel is online now   United_States
0
Reply With Quote
      10-24-2007, 01:31 PM   #20
Sedan_Clan
Banned
 
Drives: '14 335i(prev.IB,AW M3's & X5)
Join Date: Jun 2006
Location: On 2 wheels clipping an apex!

Posts: 10,921
iTrader: (25)

Quote:
Originally Posted by swamp2 View Post

Don't be a luddite. There are a few good reasons to not want an M-DCT but this doesn't cut it for me. Would you say that BMWs dual VANOS system or the engine control unit with multiple 32 bit CPUs capable of 200 million calculations per second are "too complex" or subject to to many expensive repairs after warranty? There are essential components of a modern car that are reliable for a large percentage of the lifetime of the car (if not its entire lifetime).


Sure it is, but as I implied previously, this is one less thing to have to worry about. Plus, I love my clutch pedal!
Sedan_Clan is offline   Brazil
0
Reply With Quote
      10-24-2007, 01:45 PM   #21
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,201
iTrader: (1)

Quote:
Originally Posted by Hans Delbruck View Post
Did Sam Mitani do the test and write the article? If so, then he's a good driver, and I believe it.

Otherwise, the new Evo SST trans takes a car that is already way too easy to drive fast, and makes it even easier. No wonder it's easy for an intermediate-novice-weekend track guy to go faster in the auto mode.
It was Sam Mitani.

There is nothing wrong IMO with making high performance driving easier and I think the Evo X and E92 M3 will both excel in this area. I agree with your comments about getting in over your head but hey with systems as thorough and good as DSC I say, "why not".
swamp2 is offline   United_States
0
Reply With Quote
      10-24-2007, 01:47 PM   #22
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,201
iTrader: (1)

Manual modes

Quote:
Originally Posted by mkoesel View Post
Well I don't know the answer to the last question, but from what I found when I googled there are three manual modes, just like there are three auto modes. However, I could not find a detailed explanation of the differences between them.

Sounds reasonable. I suppose you can still tweak the continuum between comfort and sport even in manual mode. If the Evo offers multiple manual modes I'd strongly bet the M3 will as well. Do share the difference between manual modes if you can figure it out. I am very interested.
swamp2 is offline   United_States
0
Reply With Quote
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 07:04 AM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST