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)
 
PYSPEED
Post Reply
 
Thread Tools Search this Thread
      07-13-2008, 09:04 PM   #1
ihyln
Banned
United_States
44
Rep
3,385
Posts

 
Drives: M3post sucks
Join Date: Apr 2008
Location: M3post sucks

iTrader: (1)

Garage List
2008 M3  [0.00]
2002 530i  [0.00]
Send a message via AIM to ihyln
DCT behavior question

I'm wondering if the following is normal... In S5 while I'm on an on-ramp I'm not depressing the pedal entirely but lightly enough to get the engine going in a hurry (not in kickdown mode either). As I shift I was getting soft jerks but I'm not getting it anymore (or at least noticing now, I'll check again tomorrow)

I don't get any soft jerks of any sort in any of the D modes. I don't feel them in S1-4 either.

Anything to worry about or is the tranny breaking in normally?
Appreciate 0
      07-13-2008, 09:14 PM   #2
FifthStreetz
O! So Sour!!
FifthStreetz's Avatar
United_States
193
Rep
15,559
Posts

 
Drives: Fast 240z / Slow M3
Join Date: Apr 2007
Location: Fort Lee, NJ

iTrader: (24)

Garage List
2008 M3  [4.75]
Yea its suppose to tug when you shift in S5. Its normal.
__________________
Appreciate 0
      07-13-2008, 09:36 PM   #3
ybbiz34
Moderator
ybbiz34's Avatar
181
Rep
4,714
Posts

 
Drives: 2013 C63 AMG Sedan
Join Date: Jul 2007
Location: USA

iTrader: (1)

The other day when I was test driving a DCT equipped car, I was driving the car in manual mode (if this has another name I apologize, as I am not quite up to par on the DCT proper terminology) and I was sitting at a stoplight in first gear. The throttle was in its most aggressive setting (I had recently just pushed the M button), and I hit the gas casually and before shifting to second I lifted up off of the pedal a bit and the car began to jerk back and forth rather violently, and the situation became increasingly complicated/worse as my foot would tap the gas again slightly as a result of the jerking. After getting rocked back and forth for a couple of seconds I finally was able to grab a shift into second gear. Needless to say, I felt like a jackass. Has anyone else experienced this, or can anyone comment on what that was all about? Was it all just a matter of throttle sensitivity or a flaw with the transmission?
__________________
'13 Iridium Silver C63 AMG Sedan (540 hp; 500 lb-ft)
Appreciate 0
      07-13-2008, 09:40 PM   #4
ihyln
Banned
United_States
44
Rep
3,385
Posts

 
Drives: M3post sucks
Join Date: Apr 2008
Location: M3post sucks

iTrader: (1)

Garage List
2008 M3  [0.00]
2002 530i  [0.00]
Send a message via AIM to ihyln
Phew, Thanks Dave! I was getting concerned. I just took it out for a spin on to a few on-ramps to double check and yup it's there. It's a good way to flatten your kidneys.

ybbiz32, it happens to me in first but not as violent as you had mentioned. It's a result of not keeping steady on the gas but when you have the Power button on it can get like that. I've learned just to keep a light foot in first coming off a red light.
Appreciate 0
      07-13-2008, 09:43 PM   #5
ybbiz34
Moderator
ybbiz34's Avatar
181
Rep
4,714
Posts

 
Drives: 2013 C63 AMG Sedan
Join Date: Jul 2007
Location: USA

iTrader: (1)

Quote:
Originally Posted by ihyln View Post
ybbiz32, it happens to me in first but not as violent as you had mentioned. It's a result of not keeping steady on the gas but when you have the Power button on it can get like that. I've learned just to keep a light foot in first coming off a red light.
Yeah that makes sense. That's what I figured was the problem. Good to know from now on.
__________________
'13 Iridium Silver C63 AMG Sedan (540 hp; 500 lb-ft)
Appreciate 0
      07-13-2008, 09:43 PM   #6
FifthStreetz
O! So Sour!!
FifthStreetz's Avatar
United_States
193
Rep
15,559
Posts

 
Drives: Fast 240z / Slow M3
Join Date: Apr 2007
Location: Fort Lee, NJ

iTrader: (24)

Garage List
2008 M3  [4.75]
Quote:
Originally Posted by ihyln View Post
Phew, Thanks Dave! I was getting concerned. I just took it out for a spin on to a few on-ramps to double check and yup it's there. It's a good way to flatten your kidneys.
No problem Shaf.

I was concerned at first too, since i was used to driving in D1-4, when i first tried S5 i was like whoa...whats this tug. I like it, the feel of the kick during spirited driving is great.
__________________
Appreciate 0
      07-13-2008, 09:45 PM   #7
FifthStreetz
O! So Sour!!
FifthStreetz's Avatar
United_States
193
Rep
15,559
Posts

 
Drives: Fast 240z / Slow M3
Join Date: Apr 2007
Location: Fort Lee, NJ

iTrader: (24)

Garage List
2008 M3  [4.75]
Quote:
Originally Posted by ybbiz34 View Post
The other day when I was test driving a DCT equipped car, I was driving the car in manual mode (if this has another name I apologize, as I am not quite up to par on the DCT proper terminology) and I was sitting at a stoplight in first gear. The throttle was in its most aggressive setting (I had recently just pushed the M button), and I hit the gas casually and before shifting to second I lifted up off of the pedal a bit and the car began to jerk back and forth rather violently, and the situation became increasingly complicated/worse as my foot would tap the gas again slightly as a result of the jerking. After getting rocked back and forth for a couple of seconds I finally was able to grab a shift into second gear. Needless to say, I felt like a jackass. Has anyone else experienced this, or can anyone comment on what that was all about? Was it all just a matter of throttle sensitivity or a flaw with the transmission?
throttle sensitivity. First gear is rather short so if you let off the trottle at 3-4k rpms and quickly step on it again its going to jerk a bit esp. since you have sport on.
__________________
Appreciate 0
      07-13-2008, 09:55 PM   #8
skierman64
Brigadier General
skierman64's Avatar
United_States
43
Rep
3,068
Posts

 
Drives: 2008 E92 Space Gray M3 & E36M3
Join Date: Dec 2006
Location: Greater St Louis Metro area

iTrader: (1)

Garage List
1998 M3 Coupe  [0.00]
2008 M3 Coupe  [0.00]
Send a message via Yahoo to skierman64
Try full throttle in S5 and see how that feels. The higher rpm the shift the bigger the jerk will be.
__________________
Get a professional motorsports full featured stopwatch app for your Blackberry here: http://appworld.blackberry.com/webstore/content/19464
Invest Wisely...The best mod for your money?? BMWCCA high performance driver's school. The mod that lasts a lifetime and improves the performance of any car you drive
Appreciate 0
      07-13-2008, 10:00 PM   #9
skierman64
Brigadier General
skierman64's Avatar
United_States
43
Rep
3,068
Posts

 
Drives: 2008 E92 Space Gray M3 & E36M3
Join Date: Dec 2006
Location: Greater St Louis Metro area

iTrader: (1)

Garage List
1998 M3 Coupe  [0.00]
2008 M3 Coupe  [0.00]
Send a message via Yahoo to skierman64
Quote:
Originally Posted by ybbiz34 View Post
The other day when I was test driving a DCT equipped car, I was driving the car in manual mode (if this has another name I apologize, as I am not quite up to par on the DCT proper terminology) and I was sitting at a stoplight in first gear. The throttle was in its most aggressive setting (I had recently just pushed the M button), and I hit the gas casually and before shifting to second I lifted up off of the pedal a bit and the car began to jerk back and forth rather violently, and the situation became increasingly complicated/worse as my foot would tap the gas again slightly as a result of the jerking. After getting rocked back and forth for a couple of seconds I finally was able to grab a shift into second gear. Needless to say, I felt like a jackass. Has anyone else experienced this, or can anyone comment on what that was all about? Was it all just a matter of throttle sensitivity or a flaw with the transmission?

Driver induced oscillations. The throttle pedal is sensitive. Putting your foot lightly against the transmission tunnel while pressing the accelerator (center console) will help prevent that as your accelerating briskly.

I had the same thing happen to me twice the first week I owned the car, but it hasn't happened since.
__________________
Get a professional motorsports full featured stopwatch app for your Blackberry here: http://appworld.blackberry.com/webstore/content/19464
Invest Wisely...The best mod for your money?? BMWCCA high performance driver's school. The mod that lasts a lifetime and improves the performance of any car you drive
Appreciate 0
      07-13-2008, 10:01 PM   #10
darkalley
Captain
United_States
18
Rep
636
Posts

 
Drives: Gone- 08 DCT SSII, 2006 SMG
Join Date: Dec 2006
Location: Current: 2014 BMW 4-Series Convert for the fiance w M Package, F150, 06 S2000, 08 911 c4s

iTrader: (0)

Quote:
Originally Posted by ybbiz34 View Post
The other day when I was test driving a DCT equipped car, I was driving the car in manual mode (if this has another name I apologize, as I am not quite up to par on the DCT proper terminology) and I was sitting at a stoplight in first gear. The throttle was in its most aggressive setting (I had recently just pushed the M button), and I hit the gas casually and before shifting to second I lifted up off of the pedal a bit and the car began to jerk back and forth rather violently, and the situation became increasingly complicated/worse as my foot would tap the gas again slightly as a result of the jerking. After getting rocked back and forth for a couple of seconds I finally was able to grab a shift into second gear. Needless to say, I felt like a jackass. Has anyone else experienced this, or can anyone comment on what that was all about? Was it all just a matter of throttle sensitivity or a flaw with the transmission?
In my smg car that would happen about once a week. in my dct it seems like once a month. the dct can, in rare occasions, become a little confused. in the smg it was called "bucking bronco". not sure if we will be bringing that over to DCT. Happens in f1 ferraris, e-gear lambos, etc. nothing to be worried about. 2000 miles on my dct and it is incredible.
__________________
2008 SSII DCT M3/Peapack/Parsippany NJ
Appreciate 0
      07-13-2008, 10:31 PM   #11
ybbiz34
Moderator
ybbiz34's Avatar
181
Rep
4,714
Posts

 
Drives: 2013 C63 AMG Sedan
Join Date: Jul 2007
Location: USA

iTrader: (1)

Quote:
Originally Posted by skierman64 View Post
Driver induced oscillations. The throttle pedal is sensitive. Putting your foot lightly against the transmission tunnel while pressing the accelerator (center console) will help prevent that as your accelerating briskly.

I had the same thing happen to me twice the first week I owned the car, but it hasn't happened since.
Quote:
Originally Posted by FifthStreetz View Post
throttle sensitivity. First gear is rather short so if you let off the trottle at 3-4k rpms and quickly step on it again its going to jerk a bit esp. since you have sport on.
Quote:
Originally Posted by darkalley View Post
In my smg car that would happen about once a week. in my dct it seems like once a month. the dct can, in rare occasions, become a little confused. in the smg it was called "bucking bronco". not sure if we will be bringing that over to DCT. Happens in f1 ferraris, e-gear lambos, etc. nothing to be worried about. 2000 miles on my dct and it is incredible.
Thanks for all of the responses and information guys. It is good to know I'm not the only one who has had that little experience. Aside from this error caused by my unfamiliarity with the transmission, and as I mentioned in my other thread, I was floored by the DCT. Remarkable transmission.
__________________
'13 Iridium Silver C63 AMG Sedan (540 hp; 500 lb-ft)
Appreciate 0
      07-14-2008, 02:13 AM   #12
e46e92love
Brigadier General
e46e92love's Avatar
United_States
37
Rep
3,059
Posts

 
Drives: e92 ///M3; X3 (wife's)
Join Date: Nov 2007
Location: The East Side of Things

iTrader: (0)

Send a message via AIM to e46e92love
Quote:
Originally Posted by FifthStreetz View Post
No problem Shaf.

I was concerned at first too, since i was used to driving in D1-4, when i first tried S5 i was like whoa...whats this tug. I like it, the feel of the kick during spirited driving is great.
Just felt that tug for the first time today (THANK skierman64 ) and its awesome.......
__________________

"...it's not about the money and not about the brand of the car, it's about handling,performance and passion......And that, no other car has all together like an M3........when you talk about the most complete car the M is invincible." --Tony Kanaan.
Appreciate 0
      07-14-2008, 08:50 AM   #13
JEllis
Brigadier General
JEllis's Avatar
84
Rep
4,793
Posts

 
Drives: E36 M3, E92 M3
Join Date: Oct 2006
Location: SD CA/Yuma

iTrader: (4)

Yep that sensitive throttle will get you every time!

Jason
__________________
http://www.m3post.com/forums/signaturepics/sigpic14547_7.gif
Appreciate 0
      07-23-2008, 12:02 AM   #14
ferrari6891
the original brown guy
ferrari6891's Avatar
United_States
11
Rep
973
Posts

 
Drives: 08 E92 M3, 11 E90 M3
Join Date: Jan 2008
Location: tenafly, nj/ boston, ma

iTrader: (3)

Garage List
2011.75 E90 M3  [3.83]
but how can you fix it because it happened to me just as I was about to race an S4....and the audi just left me in the dust because it started jerking violently...and if I go on the throttle slowly..theres no way i can win a race
Appreciate 0
      07-23-2008, 04:16 AM   #15
swamp2
Lieutenant General
swamp2's Avatar
United_States
215
Rep
10,201
Posts

 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

iTrader: (1)

The OP is talking about jerk (actually a mathematical term - the time derivative of acceleration). BMW calls this feeling surge. Humans are more sensitive to jerk than raw acceleration levels, i.e. the change in acceleration (typically over a short duration). There has been extensive discussion and debate on this topic all over the forum. Surge is both Drivelogic mode and rpm dependent. No modes but S4, S5 and S6 have surge and it is greater in each mode. As well the higher the rpm of the shift and the more you are on the pedal the more you will feel the surge. Surge will also be so high in S5 and S6 to lead to wheelspin and/or "chirp" when at very high throttle and high rpm shifts.
Appreciate 0
      07-23-2008, 05:39 AM   #16
DonM3
Captain
United Kingdom
6
Rep
629
Posts

 
Drives: AW e92 M3
Join Date: Mar 2007
Location: London

iTrader: (1)

This has happened to me on many occasions...

The violent jerking makes you look like a real idiot


Quote:
Originally Posted by ferrari6891 View Post
but how can you fix it because it happened to me just as I was about to race an S4....and the audi just left me in the dust because it started jerking violently...and if I go on the throttle slowly..theres no way i can win a race
Appreciate 0
      08-19-2008, 10:54 PM   #17
Powerslide
Captain
United_States
35
Rep
772
Posts

 
Drives: '15 AY M3 (sold 2008 E93 M3)
Join Date: Nov 2007
Location: Chicago Illinois USA

iTrader: (0)

Quote:
Originally Posted by DonM3 View Post
This has happened to me on many occasions...

The violent jerking makes you look like a real idiot
Has anyone heard whether this will be addressed with the Sept. 2008 software upgrade for M DCT equipped cars, or is this just an inherent characteristic of the transmission? It happens to me under similar circumstances referenced in the preceeding posts, about 1-2 times out of 10 while accelerating aggressively from a red light - sounds like it most likely is induced by starting out heavy on the accelerator and then easing off the throttle somewhat - followed by the "bucking bronco" or violent jerking back and forth...
Appreciate 0
      08-19-2008, 11:12 PM   #18
Dascamel
Lieutenant Colonel
Dascamel's Avatar
20
Rep
1,662
Posts

 
Drives: 2008 e92 M3, 2010 e91 328i
Join Date: Jul 2007
Location: Bakersfield, CA

iTrader: (0)

Its the same in other cars, tons of power, going off and on again with the throttle will create it everytime. If your not pushing it, just start in 2nd gear.
__________________
2008 E92 M3 Jerez Black,DCT,Fox Red ext,Prem,Tech,19", ipod/usb, CF roof and trim
2010 E91 328i Space Gray,Black int, M sport, most options
2007 Montego Blue 335i (retired)
Appreciate 0
      08-19-2008, 11:51 PM   #19
cchan
Private
0
Rep
91
Posts

 
Drives: '12 F30 328i/'11 C2S/'04 GT3
Join Date: Jun 2008
Location: SF Bay, CA

iTrader: (1)

The bucking bronco can happen in any car with a clutch. With an MT, you can disengage the clutch to stop it and let things settle down. In an SMG car, the best thing to do was upshift. Don't know if that will help in DCT though.
__________________
Golden Gate BMWCCA - Car Control Clinics
'13 C4S/'12 328i/'04 GT3
Past: '09 M3 DCT/'03 M3 SMG/'95 M3... missing an E30 I suppose...
Appreciate 0
      08-23-2008, 02:35 PM   #20
Powerslide
Captain
United_States
35
Rep
772
Posts

 
Drives: '15 AY M3 (sold 2008 E93 M3)
Join Date: Nov 2007
Location: Chicago Illinois USA

iTrader: (0)

Quote:
Originally Posted by cchan View Post
The bucking bronco can happen in any car with a clutch. With an MT, you can disengage the clutch to stop it and let things settle down. In an SMG car, the best thing to do was upshift. Don't know if that will help in DCT though.
Now that you mention that, I have noticed that upshifting helps - the bucking bronco immediately goes away...
Appreciate 0
      08-23-2008, 06:26 PM   #21
footie
Major General
footie's Avatar
No_Country
160
Rep
7,507
Posts

 
Drives: ????????????
Join Date: Oct 2007
Location: BMW M3 will get a V6TT

iTrader: (0)

Garage List
2008 E92 M3  [0.00]
Quote:
Originally Posted by swamp2 View Post
The OP is talking about jerk (actually a mathematical term - the time derivative of acceleration). BMW calls this feeling surge. Humans are more sensitive to jerk than raw acceleration levels, i.e. the change in acceleration (typically over a short duration). There has been extensive discussion and debate on this topic all over the forum. Surge is both Drivelogic mode and rpm dependent. No modes but S4, S5 and S6 have surge and it is greater in each mode. As well the higher the rpm of the shift and the more you are on the pedal the more you will feel the surge. Surge will also be so high in S5 and S6 to lead to wheelspin and/or "chirp" when at very high throttle and high rpm shifts.
I read in one of the British mags that S5's surge felt slightly stronger than S6, is this true or do both felt about the same?
Appreciate 0
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 01:14 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