BMW M3 Forum (E90 E92)

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


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Engine, Transmission, Exhaust, Drivetrain, ECU Software Modifications
 
ESS Tuning
Post Reply
 
Thread Tools Search this Thread
      12-29-2012, 11:44 PM   #1
sard
Major
 
Drives: 2008 M3
Join Date: Oct 2008
Location: Southern California

Posts: 1,328
iTrader: (1)

Send a message via AIM to sard
Anyone have their DCT downshift two gears instead of one?

Anyone ever pull their paddle to downshift only to have it actually skip 2 gears down instead of one with a single pull? I've had this happen a few times. 2008MY.
__________________

E92 M3 - DCT - 20" BBS LM-R - KW Clubsport - Akrapovic Exhaust - Powerchip Tune - Arkym Aero Kit - HID Halo
sard is offline  
0
Reply With Quote
      12-30-2012, 12:35 AM   #2
Amri215
Banned
 
Amri215's Avatar
 
Drives: 2012 Alpine White M3
Join Date: Nov 2012
Location: New Jersey

Posts: 161
iTrader: (0)

I think one thread would have been sufficient..lol
Amri215 is offline  
0
Reply With Quote
      12-30-2012, 12:49 AM   #3
sard
Major
 
Drives: 2008 M3
Join Date: Oct 2008
Location: Southern California

Posts: 1,328
iTrader: (1)

Send a message via AIM to sard
Sorry. On iPhone and it tweaked out
__________________

E92 M3 - DCT - 20" BBS LM-R - KW Clubsport - Akrapovic Exhaust - Powerchip Tune - Arkym Aero Kit - HID Halo
sard is offline  
0
Reply With Quote
      12-30-2012, 04:49 AM   #4
mlhj83
Scythe-Meister
 
mlhj83's Avatar
 
Drives: '11 E92 M3 DCT ZCP
Join Date: Aug 2011
Location: London

Posts: 1,021
iTrader: (0)

Read the manual on kick-down and pulling the downshift pedal.
mlhj83 is online now   United Kingdom
0
Reply With Quote
      12-30-2012, 04:27 PM   #5
Munit
Banned
 
Drives: m3
Join Date: Oct 2012
Location: CA

Posts: 220
iTrader: (0)

I actually do 3 pulls down on a very regular basis on the freeway. I just click it 2 or 3 times quickly. Sometimes I do the "hold the downshift paddle and press accelerator past the "click" point" but its more fun to just chuck a couple clicks and gear down, let it blip and than rocket off
Munit is offline  
0
Reply With Quote
      12-30-2012, 06:09 PM   #6
mlhj83
Scythe-Meister
 
mlhj83's Avatar
 
Drives: '11 E92 M3 DCT ZCP
Join Date: Aug 2011
Location: London

Posts: 1,021
iTrader: (0)

Quote:
Originally Posted by Munit
I actually do 3 pulls down on a very regular basis on the freeway. I just click it 2 or 3 times quickly. Sometimes I do the "hold the downshift paddle and press accelerator past the "click" point" but its more fun to just chuck a couple clicks and gear down, let it blip and than rocket off
The correct sequence is kickdown then pull the downshift pedal whilst in sequential mode.
mlhj83 is online now   United Kingdom
0
Reply With Quote
      12-30-2012, 06:25 PM   #7
skypx
Veteran U.S. Army
 
skypx's Avatar
 
Drives: ///M
Join Date: Nov 2011
Location: USA

Posts: 636
iTrader: (0)

Quote:
Originally Posted by mlhj83 View Post
The correct sequence is kickdown then pull the downshift pedal whilst in sequential mode.
Guess I really need to RTFM..... what is the result after that sequence?
skypx is offline   United_States
0
Reply With Quote
      12-30-2012, 06:26 PM   #8
sensi09
Lieutenant Colonel
 
Drives: .
Join Date: Dec 2010
Location: socal

Posts: 1,761
iTrader: (1)

I feel it's almost simultaneous, but I like to stab the throttle and pull the paddle then get off the gas a bit so I have the lowest gear ready.

When you hold the throttle down and pull the paddle to accelerate, there isn't much of surge or feeling of acceleration IMO. Feels very much like a regular auto in that regard. Either way, I think it would work much better without the detent/click point.

One thing I don't like is that right at 80, it gives you 4th gear instead of 3rd. So not the lowest gear possible. Just under 80mph though, you can get 3rd gear.
sensi09 is offline  
0
Reply With Quote
      12-30-2012, 07:07 PM   #9
sard
Major
 
Drives: 2008 M3
Join Date: Oct 2008
Location: Southern California

Posts: 1,328
iTrader: (1)

Send a message via AIM to sard
Quote:
Originally Posted by mlhj83 View Post
Read the manual on kick-down and pulling the downshift pedal.
My foot is far from activating the kick down. Like just 10% down on the pedal.
__________________

E92 M3 - DCT - 20" BBS LM-R - KW Clubsport - Akrapovic Exhaust - Powerchip Tune - Arkym Aero Kit - HID Halo
sard is offline  
0
Reply With Quote
      12-31-2012, 01:51 AM   #10
mlhj83
Scythe-Meister
 
mlhj83's Avatar
 
Drives: '11 E92 M3 DCT ZCP
Join Date: Aug 2011
Location: London

Posts: 1,021
iTrader: (0)

Quote:
Originally Posted by sensi09
I feel it's almost simultaneous, but I like to stab the throttle and pull the paddle then get off the gas a bit so I have the lowest gear ready.

When you hold the throttle down and pull the paddle to accelerate, there isn't much of surge or feeling of acceleration IMO. Feels very much like a regular auto in that regard. Either way, I think it would work much better without the detent/click point.

One thing I don't like is that right at 80, it gives you 4th gear instead of 3rd. So not the lowest gear possible. Just under 80mph though, you can get 3rd gear.
Yup, you are using the multi-downshift function as intended i.e. throttle and kick-down button fully depressed and then pull the downshift pedal once.

I too would have preferred if DCT picked 3rd gear instead of 4th but I suspect BMW M programmed a level of safety into this multi-downshift function at higher speeds to prevent too much engine braking (if you suddenly decide to lift off throttle just as DCT selects 3rd gear) or rear wheels breaking traction under acceleration. Manually selecting 3rd gear at that speed and then applying the throttle is much more controlled, thus safer.


Quote:
Originally Posted by sard
Quote:
Originally Posted by mlhj83 View Post
Read the manual on kick-down and pulling the downshift pedal.
My foot is far from activating the kick down. Like just 10% down on the pedal.
If pulling the downshift pedal once - without kick-down button depressed - results in multiple downshifts, then there is a fault somewhere, which you should demonstrate to the dealer ASAP to get it rectified. It might just be a poor electrical contact point on the downshift pedal that momentarily loses electrical contact when the pedal is pulled, and then regains electrical contact, thus interpreting this as 2 pulls of the downshift pedal.


Quote:
Originally Posted by skypx
Quote:
Originally Posted by mlhj83 View Post
The correct sequence is kickdown then pull the downshift pedal whilst in sequential mode.
Guess I really need to RTFM..... what is the result after that sequence?
As stated in my replies above, DCT downshifts multiple gears in sequential mode, so you don't have to pull the downshift pedal multiple times. This function does have its benefits, but I prefer to choose my gear first, then apply the throttle, as it's safer than having a fully depressed throttle while DCT automatically downshifts multiple gears for you.

Last edited by mlhj83; 12-31-2012 at 04:42 AM.
mlhj83 is online now   United Kingdom
0
Reply With Quote
      10-09-2013, 01:02 PM   #11
tdott
First Lieutenant
 
Drives: M3
Join Date: Nov 2010
Location: T.Dot

Posts: 385
iTrader: (1)

The fact that you'd have to be at WOT to downshift makes that features useless to me.
__________________
tdott is offline  
0
Reply With Quote
      10-09-2013, 01:17 PM   #12
KmndntKlink
Lieutenant
 
KmndntKlink's Avatar
 
Drives: 2010 e92 m3
Join Date: Aug 2012
Location: Toronto

Posts: 409
iTrader: (3)

Quote:
Originally Posted by tdott View Post
The fact that you'd have to be at WOT to downshift makes that features useless to me.
yeah exactly, I can't wrap my head around it & I've never used it lol, by the time I press downshift after full throttle, I'm already @ the top of the rev range. I just downshift once or twice then hit it.

although in auto mode it works ok, still a lot of lag to go from 7th-4th, basically makes it as slow as a turbo'd car IMHO. I just manually select the gear I want a head of time, which I think is how you're supposed to be doing it :P
__________________
E92 ///M3 in Dakar Yellow, M-DCT, iDrive, 220M OEM rims, Active Autowerke Green filter, Turner Motorsport test pipes, BPM stage 2 tune, Stoptech ST-40 F+R in yellow.
KmndntKlink is offline   Canada
0
Reply With Quote
      10-09-2013, 01:17 PM   #13
Jive
First Lieutenant
 
Jive's Avatar
 
Drives: my gf crazy
Join Date: Dec 2010
Location: San Francisco, CA

Posts: 346
iTrader: (0)

Quote:
Originally Posted by mlhj83 View Post
The correct sequence is kickdown then pull the downshift pedal whilst in sequential mode.
I was under the impression that this isn't great for the clutch due to potential slippage?
__________________
2013 E92 M3 Mineral White
Jive is offline  
0
Reply With Quote
      10-09-2013, 04:03 PM   #14
mlhj83
Scythe-Meister
 
mlhj83's Avatar
 
Drives: '11 E92 M3 DCT ZCP
Join Date: Aug 2011
Location: London

Posts: 1,021
iTrader: (0)

Quote:
Originally Posted by Jive View Post
I was under the impression that this isn't great for the clutch due to potential slippage?
There shouldn't be any clutch slippage as the computer controls the rpm and gearbox - you are simply giving it an instruction. This sequence is as per the handbook.
mlhj83 is online now   United Kingdom
0
Reply With Quote
      10-09-2013, 04:13 PM   #15
rjd598
Brigadier General
 
rjd598's Avatar
 
Drives: 10' M3
Join Date: Jan 2009
Location: San Diego,CA

Posts: 4,468
iTrader: (2)

Garage List
2010 BMW M3  [4.50]
1999 BMW M3  [0.00]
.
Attached Images
 
__________________
10 E90 M3/dct/ztp/zpp/heated seats/eps/19'/iPod
retired- 08 535i/nav/prem./L7/ipod
retired- 06 325i/nav/prem./sat/xenons/style 128

rjd598 is offline   United_States
0
Reply With Quote
      10-09-2013, 04:13 PM   #16
tdott
First Lieutenant
 
Drives: M3
Join Date: Nov 2010
Location: T.Dot

Posts: 385
iTrader: (1)

Quote:
Originally Posted by mlhj83 View Post
There shouldn't be any clutch slippage as the computer controls the rpm and gearbox - you are simply giving it an instruction. This sequence is as per the handbook.
That doesn't mean it doesn't use or 'wear' the clutch.
__________________
tdott is offline  
0
Reply With Quote
      10-09-2013, 07:18 PM   #17
mlhj83
Scythe-Meister
 
mlhj83's Avatar
 
Drives: '11 E92 M3 DCT ZCP
Join Date: Aug 2011
Location: London

Posts: 1,021
iTrader: (0)

Quote:
Originally Posted by tdott
Quote:
Originally Posted by mlhj83 View Post
There shouldn't be any clutch slippage as the computer controls the rpm and gearbox - you are simply giving it an instruction. This sequence is as per the handbook.
That doesn't mean it doesn't use or 'wear' the clutch.
The computers involved ensure that the rpm is matched to the gear; the rpm will not be allowed to go beyond the optimal engine speed when downshifting to a particular gear.

Clutch slip happens when there is a speed mismatch between the rpm and clutch.
mlhj83 is online now   United Kingdom
0
Reply With Quote
      10-09-2013, 07:46 PM   #18
tdott
First Lieutenant
 
Drives: M3
Join Date: Nov 2010
Location: T.Dot

Posts: 385
iTrader: (1)

Quote:
Originally Posted by mlhj83 View Post
Clutch slip happens when there is a speed mismatch between the rpm and clutch.
Everytime a gear is engaged there is some degree of 'slip' which in turn wears the clutch very slightly, during WOT shift in S5 or S6 that puts the most wear on the clutch.
__________________
tdott is offline  
0
Reply With Quote
      10-10-2013, 05:10 PM   #19
mlhj83
Scythe-Meister
 
mlhj83's Avatar
 
Drives: '11 E92 M3 DCT ZCP
Join Date: Aug 2011
Location: London

Posts: 1,021
iTrader: (0)

Quote:
Originally Posted by tdott
Quote:
Originally Posted by mlhj83 View Post
Clutch slip happens when there is a speed mismatch between the rpm and clutch.
Everytime a gear is engaged there is some degree of 'slip' which in turn wears the clutch very slightly, during WOT shift in S5 or S6 that puts the most wear on the clutch.
Of course, otherwise clutches would never wear out, but the above multi-downshift procedure won't cause any further wear than shifting at wide open throttle, which is what the gearbox has been designed to cope with - assuming the car is standard and functioning normally of course.
mlhj83 is online now   United Kingdom
0
Reply With Quote
      10-30-2013, 10:09 PM   #20
swifty
Major
 
Drives: FO M3
Join Date: Aug 2008
Location: canada

Posts: 1,198
iTrader: (4)

Just got the M. What do you mean by kickdown. Sorry a newbie.
__________________
__________________
Past: '89 Cutlass, Alpine white e46 323i, Jet Black e39 530, Sapphire Black e60 530, Space Grey 2008 e92 335, Mineral White 2011 e92 335

Current: FO e92 M3
swifty is offline  
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 04:33 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