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
 
GT Haus
Post Reply
 
Thread Tools Search this Thread
      08-23-2008, 05:36 AM   #1
swamp2
Major General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 9,586
iTrader: (1)

PRELIMINARY M-DCT shift times - results and data

I have done some preliminary measurements of the M-DCT shift times. The numbers are not too much of a surprise and are quite consistent with my previous estimates and rumored and quoted values for other DC vehicles. However, the differences between modes with and without surge are quite surprising.

For those that don't want to read the remaining details nor actually look at the data the shift times likely vary from about 30 to 200 ms.

Thanks again to the members who helped fund the purchase of the equipment to accomplish these measurements, T-Bone, lucid, TLud and OC Kid. The thread that proposed this is located here. The equipment used is listed here as well. We would still like to test many more cars listed on that thread, if you or someone you know would volunteer their car (preferably in the Southern California or Boston area) please PM me. Of course the process to get better, cleaner and more accurate data will be refined before moving forward with a lot more testing.

Since these measurements involve ONLY the time for the actuation of the clutches they DO NOT include the delay which has already been noted in S modes between the actuation of the paddle/stick and the beginning of the clutch actuation (and hence any measureable changes in acceleration). So until that can be better instrumented and tested these are shift times in D modes or partial shift time NOT INCLUDING any shift lag.

We know already that not all gears, all modes and all rpms produce equal shift times and these are the approximate measured range. When including the 1->2 shift in LC mode and the 6->7 shift I would expect that range to widen (just an educated guess here to about 20 to 400 ms. The former figure being maybe D2 6-7th at low throttle and the latter for 1-2 under LC as it really slurs this shift, while not sacrificing acceleration.

Caveats:
  • This raw data clearly needs better filtering or averaging due to the fairly high signal to noise ratio.
  • Contributing factors to the signal to noise ratio include:
    • A crude preliminary zip tie mounting of the accelerometer on the left upper door hinge bracket (I could indeed get my door shut without damaging the accel nor its cable ). Proper mounting will require the fabrication of a small aluminum bracket that can be bolted to a seat rail or some other equivalently rigid part of the vehicle.
    • A prior overload of the input voltage to the accel due to an error on documentation included with it.
  • Deciding exactly where a shift begins and ends is subject to a great deal of interpretation especially with the preliminary nature of the raw data. I would estimate about a 25% error is possible here.
  • Data thus far has only been taken for shifts 1->2, 2->3 and 3->4 at medium to full throttle. Mostly to avoid ridiculous speeds on public roads. The aforementioned high signal to noise at this point prevents measurement of shift times at low throttle.
  • Although I feel the shift times are fairly consistent across all of the shifts I observed in the complete data and there has been no "cherry picking" of results to provide better or lower times, results shown below absolutely have been "cherry picked" to provide the most clarity of the distinction of the shift itself amongst the fairly noisy data. There are some shifts where you just can not see anything useful.

Data and results:

First graph

Mode: D3
Power: Normal
Throttle (qualitative): medium to high, close to WOT
Shift: 3->4
Data sampling rate: 300 Hz
Vertical axis: acceleration in g's
Shift time: 32 +/- 5 ms

Second graph

Mode: S4 (recall this means the transmission will exhibit surge or more precisely stated a noticeable jerk)
Power: Normal
Throttle (qualitative): medium to high, close to WOT
Shift 2->3
Data sampling rate: 500 Hz
Vertical axis: acceleration in g's
Shift time: 200 +/- 50 ms

Discussion:

The 30 or so ms observed in D modes is consistent with figures discussed for VAG DSG. Many sources quoted 8 ms but a more credible source provided a very similar figure. 8 ms has always seemed way too low given it is still a mechnical and hydraulic system. There are about 10 individual sample points across the duration of the shift in the first graph. The acceleration profile shows the steady state acceleration drop as the first clutch is disengaged very quickly followed by an equal duration surge of a higher magnitude as the second clutch engages.

The S4 shift time is a big surprise. They certainly feel faster than the S3 shifts but it is psychological. The mathematical surge/jerk in S3 is actually much greater (a large jump in g force over a shorter duration) compared to the more plateau like positive and lengthy acceleration profile in S4. I think what is happening is that the jerk in S3 is simply so short we just don't feel it, whereas the much more lengthy profile, all at an increased acceleration compared the the steady state, both before and after the shift provides this jerk/surge/"clunk" that we know so well from modes S4->S6.

A quick calculation of the extra speed that this surge provides compared to the wash in D3 is given by:

ΔV = a x t = 3/8 g x .15 s ≈ 0.6 m/s ≈ 1.2 mph

This is the relative gain comparing the mph after the 2->3 shift in S4 vs. D3. So again footie, my friend, S4->S6 with surge does not shift faster than D modes but it is faster. The former result I believe is quite novel but the later one was what I and others have been saying all along.
Attached Images
  
swamp2 is offline   United_States
0
Reply With Quote
      08-23-2008, 07:10 AM   #2
footie
Major General
 
footie's Avatar
 
Drives: ????????????
Join Date: Oct 2007
Location: BMW M3 will get a V6TT

Posts: 7,507
iTrader: (0)

Garage List
2008 E92 M3  [0.00]
No problems in admitting that the surge is proving to provide an additional increase in forward momentum, so we are roughly looking at a 1 mph surge over D3, but D3 is completing it's shift 6 times quicker, is that about right or have I misunderstood what you were saying.

Next we need to compare the acceleration times between 20~120mph between D3 and S4, that will determine how much of a true benefit the surge is providing other than the feeling of sportiness which is the most noticeable benefit.
footie is offline   No_Country
0
Reply With Quote
      08-23-2008, 11:22 AM   #3
Dascamel
Lieutenant Colonel
 
Dascamel's Avatar
 
Drives: 2008 e92 M3, 2010 e91 328i
Join Date: Jul 2007
Location: Bakersfield, CA

Posts: 1,662
iTrader: (0)

Even though the shift can be 200ms, is the car still providing power to the tires during the shift?
__________________
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)
Dascamel is offline  
0
Reply With Quote
      08-23-2008, 11:45 AM   #4
lucid
Major General
 
lucid's Avatar
 
Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

Posts: 8,034
iTrader: (0)

Thanks Swamp. This is rather interesting preliminary data. I am looking forward to seeing more measurements taken at a higher sampling rate (300 Hz on the first graph seems to be just the bare minimum for capturing anything meaningful), and a comparison of the same shift, say 2->3, in D and S modes under WOT so that we can isolate any effects of your throttle input during the shift, which might not be constant (I assume that's why we are not seeing a significant drop in acceleration after the 2->3 shift, which should happen due to the change in gearing, or is it just the scale of the y-axis combined with the noise that makes it difficult to observe this?). I realize that is not easy to do on public roads though. Is there any reason why you are not using the 1kHz sampling rate? I believe the accelerometer will do that, right? And, yes mounting the accelerometer rigidly should decrease noise significantly.
__________________
lucid is offline   United_States
0
Reply With Quote
      08-23-2008, 12:13 PM   #5
kenwelch
First Lieutenant
 
Drives: 2008 E92 M3 M-DCT
Join Date: Dec 2006
Location: Mission Viejo, CA

Posts: 339
iTrader: (0)

Quote:
Originally Posted by swamp2 View Post
[*]A crude preliminary zip tie mounting of the accelerometer on the left upper door hinge bracket (I could indeed get my door shut without damaging the accel nor its cable ). Proper mounting will require the fabrication of a small aluminum bracket that can be bolted to a seat rail or some other equivalently rigid part of the vehicle.
I could make the sensor mounting bracket needed using my car for the pattern, but would need a picture of the sensor and mounting dimensions. I have the sheet aluminum and equipment. The bracket could be to your office about Thursday next week or we could meet on your way home.
kenwelch is offline   United_States
0
Reply With Quote
      08-23-2008, 02:23 PM   #6
T Bone
Brigadier General
 
T Bone's Avatar
 
Drives: 2008 335xi Coupe
Join Date: Feb 2007
Location: The land where we kill baby seals

Posts: 4,021
iTrader: (0)

Thanks Swamp...good initial set. It would be good if you can compile statistics on the shift programs.

I.e. get shift times for all shifts in S and D mode. Then we can do figure out mean times for each gear shift by program.
__________________
"Aerodynamics are for people who cannot build engines"......Enzo Ferrari
T Bone is offline  
0
Reply With Quote
      08-23-2008, 02:30 PM   #7
T Bone
Brigadier General
 
T Bone's Avatar
 
Drives: 2008 335xi Coupe
Join Date: Feb 2007
Location: The land where we kill baby seals

Posts: 4,021
iTrader: (0)

Swamp - please see http://www.m3post.com/forums/showthread.php?p=3213213

I would love to see some SMG3 data once you sort out the methodology.
__________________
"Aerodynamics are for people who cannot build engines"......Enzo Ferrari
T Bone is offline  
0
Reply With Quote
      08-23-2008, 04:00 PM   #8
swamp2
Major General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 9,586
iTrader: (1)

Quote:
Originally Posted by Dascamel View Post
Even though the shift can be 200ms, is the car still providing power to the tires during the shift?
The car is not only accelerating during the entire S4 shift, it is accelerating MORE than the background, steady state acceleration (i.e. that due to the car pretty much being pegged!). In D3 the car actually very briefly (~15 ms) decelerates, but again one can't feel it.
swamp2 is offline   United_States
0
Reply With Quote
      08-23-2008, 04:11 PM   #9
swamp2
Major General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 9,586
iTrader: (1)

Quote:
Originally Posted by lucid View Post
Thanks Swamp. This is rather interesting preliminary data. I am looking forward to seeing more measurements taken at a higher sampling rate (300 Hz on the first graph seems to be just the bare minimum for capturing anything meaningful), and a comparison of the same shift, say 2->3, in D and S modes under WOT so that we can isolate any effects of your throttle input during the shift, which might not be constant (I assume that's why we are not seeing a significant drop in acceleration after the 2->3 shift, which should happen due to the change in gearing, or is it just the scale of the y-axis combined with the noise that makes it difficult to observe this?). I realize that is not easy to do on public roads though. Is there any reason why you are not using the 1kHz sampling rate? I believe the accelerometer will do that, right? And, yes mounting the accelerometer rigidly should decrease noise significantly.
  • 300Hz does provide enough resolution to get about 10 sample points across the shorter D3 shift. So it is providing shape and duration. For example even along the largest slope sections there are quite a few samples. Those slopes, as far as I can tell are real.
  • If you look at the data on a longer time scale the steadily decreasing acceleration before and after the shifts is clear. Noise is a problem and the accel may (pure speculation) have a slightly transient sensitivity after the large jerk shift events. However you can clearly see this effect on the other trace, despite the similarly short duration covered.
  • Just did not bother with 1kHz yet. 300 seemed sufficient. I will try it eventually.
swamp2 is offline   United_States
0
Reply With Quote
      08-23-2008, 04:35 PM   #10
swamp2
Major General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 9,586
iTrader: (1)

Quote:
Originally Posted by kenwelch View Post
I could make the sensor mounting bracket needed using my car for the pattern, but would need a picture of the sensor and mounting dimensions. I have the sheet aluminum and equipment. The bracket could be to your office about Thursday next week or we could meet on your way home.
Great Ken that is fantastic. We can then measure some shift times in your car, just for the sake of obtaining consistency.

I dug around a bit and thought the seat rails would be the best location for easy access and very rigid mounting, while remaining on the interior of the car. However, the attachment of the bracket to the rails is not 100% straight forward and it should be as rigid as possible. Do note you can easily pop the protective plastic cover right off the front of the seat rails. I am certainly open to other ideas.

The accel dimensions and mounting dimensions are given in the attached pdf. The mounting screws are M2 x 12 FHCS. I could make it slightly easier for you by dropping the actual accel off, that way there could be no uncertainty.

You should make an attempt to get the accel as normal to both the ground and direction of travel as possible. Definitely not a huge deal, nor does it need to be perfect, but this would be a goal.

Last but not least, I strongly believe the braket should be made of bar instead of sheet. You probably meant that. I use "sheet" for any material measured in gages and "bar" for the stuff in inches beginning around 1/8". Based on the screws and accel thickness my suggestion would be 3/16" thick minimum.

Thanks again!
Attached Images
File Type: pdf 7521A.pdf (313.3 KB, 122 views)
swamp2 is offline   United_States
0
Reply With Quote
      08-23-2008, 04:36 PM   #11
swamp2
Major General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 9,586
iTrader: (1)

Quote:
Originally Posted by T Bone View Post
Swamp - please see http://www.m3post.com/forums/showthread.php?p=3213213

I would love to see some SMG3 data once you sort out the methodology.
Wrong link! Have your M5 boy drop me a line. If he is not a member here I have pm'd you my contact details.
swamp2 is offline   United_States
0
Reply With Quote
      08-23-2008, 05:28 PM   #12
kenwelch
First Lieutenant
 
Drives: 2008 E92 M3 M-DCT
Join Date: Dec 2006
Location: Mission Viejo, CA

Posts: 339
iTrader: (0)

I will check Sunday to see what material I have
(near 3/16") and use the PDF sensor dimensions to layout a design. I don't think I will need the sensor to do the layout. I also read through the Dytran technical material on mounting and will follow their recommendations. The attached PDF was in their tech education link at the bottom of thier web page.

http://www.dytran.com/go.cfm/en-us/c...ucation/x?SID=

There is also additional info there that might help with the testing.
Attached Images
File Type: pdf accelerometer mounting considerations.pdf (221.9 KB, 109 views)
kenwelch is offline   United_States
0
Reply With Quote
      08-23-2008, 06:14 PM   #13
footie
Major General
 
footie's Avatar
 
Drives: ????????????
Join Date: Oct 2007
Location: BMW M3 will get a V6TT

Posts: 7,507
iTrader: (0)

Garage List
2008 E92 M3  [0.00]
Quote:
Originally Posted by T Bone View Post
Thanks Swamp...good initial set. It would be good if you can compile statistics on the shift programs.

I.e. get shift times for all shifts in S and D mode. Then we can do figure out mean times for each gear shift by program.
To be perfectly honest the list of possible tests that could be conducted on this one gearbox is endless and to us car geeks it would be totally interesting. The thing I find most interesting and seems to defy logical (if I am reading it right) is that the gearbox, even on the longer 200ms shifts is providing not only power during this period but it's an increased power (i.e. surge) through the length of the shift.

DSG seems to performs like s3 by the sound of it, i.e. ultra quick shifts with the surge which isn't noticeable, why BMW and Porsche are choosing to increase the shift duration to make the surge felt is unknown, I agree that it feels good when you are 'ON IT' and as Swamp has found it does generate a kick of approx >1mph. The next thing needed to be ascertained is whether this longer duration shift with felt surge over the ultra quick shift with the greater surge that isn't felt actually benefits the overall acceleration times over a set discipline (20~120mph). This will be very interesting to see how that one plays out.
footie is offline   No_Country
0
Reply With Quote
      08-23-2008, 06:16 PM   #14
T Bone
Brigadier General
 
T Bone's Avatar
 
Drives: 2008 335xi Coupe
Join Date: Feb 2007
Location: The land where we kill baby seals

Posts: 4,021
iTrader: (0)

Quote:
Originally Posted by swamp2 View Post
Wrong link! Have your M5 boy drop me a line. If he is not a member here I have pm'd you my contact details.

Here is the right URL

http://www.m5board.com/vbulletin/e60...ml#post1397994
__________________
"Aerodynamics are for people who cannot build engines"......Enzo Ferrari
T Bone is offline  
0
Reply With Quote
      08-23-2008, 06:41 PM   #15
lucid
Major General
 
lucid's Avatar
 
Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

Posts: 8,034
iTrader: (0)

Quote:
Originally Posted by swamp2 View Post
  • 300Hz does provide enough resolution to get about 10 sample points across the shorter D3 shift. So it is providing shape and duration. For example even along the largest slope sections there are quite a few samples. Those slopes, as far as I can tell are real.
  • If you look at the data on a longer time scale the steadily decreasing acceleration before and after the shifts is clear. Noise is a problem and the accel may (pure speculation) have a slightly transient sensitivity after the large jerk shift events. However you can clearly see this effect on the other trace, despite the similarly short duration covered.
Yes, the drop is much more visible on the second graph. I was wondering what the the signal looked like up to a second before and after.

I saw your earlier comment about 10 data points within the interval. Visually, it seems less, but I guess some of the points line up well with the lines. Regardless, it would be good to have more.
__________________
lucid is offline   United_States
0
Reply With Quote
      08-23-2008, 06:52 PM   #16
ArtPE
Banned
 
Drives: e46 M3
Join Date: Dec 2007
Location: Earth

Posts: 471
iTrader: (0)

now that is a hell of a post...great in fact...

surprising results, contrary to intuition, but explained clearly...nice

this is the good shyte
ArtPE is offline  
0
Reply With Quote
      08-23-2008, 06:56 PM   #17
ArtPE
Banned
 
Drives: e46 M3
Join Date: Dec 2007
Location: Earth

Posts: 471
iTrader: (0)

Quote:
Originally Posted by lucid View Post
Thanks Swamp. This is rather interesting preliminary data. I am looking forward to seeing more measurements taken at a higher sampling rate (300 Hz on the first graph seems to be just the bare minimum for capturing anything meaningful), and a comparison of the same shift, say 2->3, in D and S modes under WOT so that we can isolate any effects of your throttle input during the shift, which might not be constant (I assume that's why we are not seeing a significant drop in acceleration after the 2->3 shift, which should happen due to the change in gearing, or is it just the scale of the y-axis combined with the noise that makes it difficult to observe this?). I realize that is not easy to do on public roads though. Is there any reason why you are not using the 1kHz sampling rate? I believe the accelerometer will do that, right? And, yes mounting the accelerometer rigidly should decrease noise significantly.
300 hz is plenty...that's a sample every 3.3 ms...generally speaking you need to sample at 2x the frequency of the signal you are trying to capture data for...

so if the shift is 30 ms, 3.3 is 9x's...
3.3 is theoretically enough to capture 8 ms...

Nyquist-Shannon
If a function f(t) contains no frequencies higher than W cps, it is completely determined by giving its ordinates at a series of points spaced 1/(2W) seconds apart.
ArtPE is offline  
0
Reply With Quote
      08-23-2008, 07:23 PM   #18
lucid
Major General
 
lucid's Avatar
 
Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

Posts: 8,034
iTrader: (0)

Quote:
Originally Posted by ArtPE View Post
300 hz is plenty...that's a sample every 3.3 ms...generally speaking you need to sample at 2x the frequency of the signal you are trying to capture data for...

so if the shift is 30 ms, 3.3 is 9x's...
3.3 is theoretically enough to capture 8 ms...

Nyquist-Shannon
If a function f(t) contains no frequencies higher than W cps, it is completely determined by giving its ordinates at a series of points spaced 1/(2W) seconds apart.
Not if you want to be more descriptive of what exactly is happening during the shift. It would also help identify the transitions better. It is possible that the first shift is longer than 35 ms for instance. But the noise needs to be reduced first.
lucid is offline   United_States
0
Reply With Quote
      08-23-2008, 07:40 PM   #19
ArtPE
Banned
 
Drives: e46 M3
Join Date: Dec 2007
Location: Earth

Posts: 471
iTrader: (0)

Quote:
Originally Posted by lucid View Post
Not if you want to be descriptive of what exactly is happening during the shift. It would also help identify the transitions better. It is possible that the first shift is longer than 35 ms for instance. But the noise needs to be reduced first.
I guess it depends on what the signal or event is...
I'm thinking it's the shift, not the noise...
and as swamp stated, he got good transitons and reversal of direction...

obviously more is better...but the Nyquist theorem is valid...it's how they cram so much signal on the net, phones, TV, etc. and not lose any information...

it would be better, as he stated, if filtering was applied...but that has risk too, filtering out signal along with noise...but if you only filter stuff outside 2x's the bandwidth you should not lose any information...

it's one reason 44.1khz was used for cd's, basically 2x's the range of human hearing of 20khz...

signal theory is manipulated in the f domain, not t....that way you can see the f's where the energy (information) lies...

I'd like to see the raw data transformed into the frequency domain with matlab

I bet the first one would have a spike at say 3f and f, discard the 3f...filter
result in t; flat line with an asymetric sine wave at the shift

the second one would have a spike at say 10f and f, discard the 10f...filter
resul in t; flat line with a pulse at the shift

Last edited by ArtPE; 08-23-2008 at 07:55 PM.
ArtPE is offline  
0
Reply With Quote
      08-23-2008, 08:11 PM   #20
Irb Digital
Lieutenant
 
Irb Digital's Avatar
 
Drives: ///M E90 MANual Jerez
Join Date: Aug 2008
Location: FL

Posts: 458
iTrader: (0)

Send a message via AIM to Irb Digital
Quote:
Originally Posted by footie View Post
To be perfectly honest the list of possible tests that could be conducted on this one gearbox is endless and to us car geeks it would be totally interesting. The thing I find most interesting and seems to defy logical (if I am reading it right) is that the gearbox, even on the longer 200ms shifts is providing not only power during this period but it's an increased power (i.e. surge) through the length of the shift.

DSG seems to performs like s3 by the sound of it, i.e. ultra quick shifts with the surge which isn't noticeable, why BMW and Porsche are choosing to increase the shift duration to make the surge felt is unknown, I agree that it feels good when you are 'ON IT' and as Swamp has found it does generate a kick of approx >1mph. The next thing needed to be ascertained is whether this longer duration shift with felt surge over the ultra quick shift with the greater surge that isn't felt actually benefits the overall acceleration times over a set discipline (20~120mph). This will be very interesting to see how that one plays out.


This is also what I'm getting from their test. I've also bolded what I'd really like to know. What is going to get you the best performance

Awesome stuff guys, this is the kind of stuff that really impresses me about the M family. Just wanted to give a thanks to you guys for doing something like this and getting some great info.

Irb Digital is offline   United_States
0
Reply With Quote
      08-23-2008, 08:17 PM   #21
e46e92love
Brigadier General
 
e46e92love's Avatar
 
Drives: e92 ///M3; X3 (wife's)
Join Date: Nov 2007
Location: The East Side of Things

Posts: 3,026
iTrader: (0)

Send a message via AIM to e46e92love
Quote:
Originally Posted by footie View Post
The next thing needed to be ascertained is whether this longer duration shift with felt surge over the ultra quick shift with the greater surge that isn't felt actually benefits the overall acceleration times over a set discipline (20~120mph). This will be very interesting to see how that one plays out.
Thats exactly what I was thinking.......

How the hell is a D mode shifting faster than S4, is BMW truly slowing down the shift so that the "surge" is not "slurred" through a quick and smooth shift? With the extra 1.2mph in speed you get from the "surge" if they could take that and the shift times of the D3 mode, isn't that the idea situation? How is S4 so much slower in the shift and how can that be good for performance?

Sorry if I sound ignorant......
__________________

"...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.
e46e92love is offline   United_States
0
Reply With Quote
      08-23-2008, 08:40 PM   #22
Dascamel
Lieutenant Colonel
 
Dascamel's Avatar
 
Drives: 2008 e92 M3, 2010 e91 328i
Join Date: Jul 2007
Location: Bakersfield, CA

Posts: 1,662
iTrader: (0)

Quote:
Originally Posted by swamp2 View Post
The car is not only accelerating during the entire S4 shift, it is accelerating MORE than the background, steady state acceleration (i.e. that due to the car pretty much being pegged!). In D3 the car actually very briefly (~15 ms) decelerates, but again one can't feel it.
Thats crazy! Regarding the shift delay. I know we need more data but, been driving around last couple days in a nice calm manner(break in), the shifts have always been fairly responsive. I click it changes almost instantly...
__________________
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)
Dascamel 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 12:01 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