|
|
07-29-2008, 02:07 PM | #23 | ||
Major General
1109
Rep 8,014
Posts |
Quote:
Quote:
And here's the link http://www.rennteam.com/showflat.php...r=449592&page= I just wished I could find that spec sheet, I will have to ask for another copy and scan it for you. As for the other part of your request I don't see the point as no matter which I say you will disagree, as per normal. The only thing I am interested in is the knowledge that I know I am correct. P.S. To back up Kerso F1 and my claims of the 200ms for Audi, there's some link. http://www.worldcarfans.com/9080604....etails-surface http://www.autoblog.com/2008/06/03/p...percharged-s4/ http://www.carmagazine.co.uk/News/Se...s/?&R=EPI-6149 |
||
Appreciate
0
|
07-29-2008, 03:57 PM | #24 | ||
Lieutenant General
609
Rep 10,407
Posts |
Quote:
That fellow from Croatia does not know the DCT shift time at 160ms. If anyone knew it in the world (outside of BMW) it is likely enigma. Quote:
Recall these important details on shift times. You really should know this by now... 1. Shift times for DCs vary by gear and rpm 2. Quoted shift times may or may not include the lag and are not very meaningful without qualifying that. 3. Some manufacturers quote max times with lag, other quote minimums without lag. Again numbers are a bit meaningless without qualifications/clarifications. Oh and always, ust like you do 100% of the time avoid the direct questions which ask you to precisely state you case about something technical. You just can't do it. I find it mildly entertaining. Hence half of my banter with you. Save the technical topics for the big boys. Keep up the good work foot. |
||
Appreciate
0
|
07-29-2008, 05:40 PM | #25 |
Major General
1109
Rep 8,014
Posts |
Well if enigma knows then why isn't he sharing it with the rest of us. The figure I was told for the Audi setup is currently 200ms, in the buff on the Porsche says the same thing and Nissan also say the same. That's three out of the five companies currently selling DCT transmissions, the odds are sort of stacked in my favour don't you think.
With the exception of this guy Kerso F1 the rest are very respected outfits with a long history for accurate info on future developments. I am only providing you with evidence that the knowledge of these things are out there and are the same as I already know, if you disregard them as you do with most things that don't fit in swampie's ideal world then that's your problem not mine. |
Appreciate
0
|
07-29-2008, 08:04 PM | #26 | |
Lieutenant General
609
Rep 10,407
Posts |
Quote:
Let me summarize all of what you know about DCT shift times: -Nissan says 200ms, ZERO qualification as to what is really means -Some web sites say 200ms for VAG, ZERO qualification as to what is really means -Some random user says 160ms for BMW, again no qualification, getting the pattern here.... Don't get me wrong, I do believe that including lag, syncro movement and both clutch operations most DCTs are in the 200ms ballpark but that is qualfied and far from solid proof. I also think this is a worst case type of spec. WOT near redline, 5->6 will be CONSIDERABLY faster. |
|
Appreciate
0
|
07-29-2008, 08:40 PM | #27 |
Major General
374
Rep 8,033
Posts |
Given the level of interest in shift times, I am surprised that a respectable magazine still has not come up with a more sensitive setup to measure the accelerations of different DC cars during shifting. It's not rocket science, and it's a just a matter of someone having the will to put together a system with the required frequency response. What kind of accelerometers do the current motorsport-related data acquisition systems utilize by the way? I assume measuring the delay would require tapping into the wiring of the shifter to detect the input signal.
__________________
|
Appreciate
0
|
07-29-2008, 11:22 PM | #28 | |
Lieutenant General
609
Rep 10,407
Posts |
Quote:
Last edited by swamp2; 07-30-2008 at 01:59 AM.. |
|
Appreciate
0
|
07-30-2008, 02:24 AM | #29 | |
Major General
1109
Rep 8,014
Posts |
Quote:
I posted a video of a Fifthgear review of the DSG and around 1:12s in they show a cut away of the gearbox doing a shift. Here's it again. Remember the gears overlap a bit that is why you feel no drop off in acceleration and why the shift is in the low milliseconds. |
|
Appreciate
0
|
07-30-2008, 05:37 AM | #30 | |
Lieutenant General
609
Rep 10,407
Posts |
Quote:
You are aware that modern scientific equipment can measure picoseconds. This is only a billion times faster . Pretty crude accelerometers can EASILY measure single ms. |
|
Appreciate
0
|
07-30-2008, 06:08 AM | #31 | |
Major General
1109
Rep 8,014
Posts |
Quote:
As you rightly say the technical stuff is your field and I appreciate your input if always a little anal. |
|
Appreciate
0
|
07-30-2008, 09:21 AM | #32 |
Major General
374
Rep 8,033
Posts |
It will be pretty obvious when you look at the charts and see the acceleration drop when the torque drops. There will be two reasons for the drop in torque (excluding any torque curve and transient inertia related effects): the drop in gearing and the clutches disengaging/engaging. The former can be separated from the latter as the former should result in a permanent and somewhat stable offset in the acceleration reading. It would be almost impossible to perfectly overlap the clutch engagement/disengagement, and if you get it wrong, you'll end up with excess clutch wear. It wouldn't make sense to go for it although they probably went for a partial overlap in the more agressive settings. It is easy to pick up a sensor that operates at the 10 kHz range. That means it would take a measurement every 1/10000 of a second, which should be enough resolution for this task.
__________________
Last edited by lucid; 07-30-2008 at 09:45 AM.. |
Appreciate
0
|
07-30-2008, 09:49 AM | #33 | |
Major General
374
Rep 8,033
Posts |
Quote:
__________________
|
|
Appreciate
0
|
07-30-2008, 02:04 PM | #34 |
Lieutenant General
609
Rep 10,407
Posts |
I did post the suggestion that I would take donations. 10 people would be fine at <100 per person. I just don't think the folks here are techie enough to donate $100. Let's see what enigma has for us and go from there....
|
Appreciate
0
|
07-31-2008, 03:25 PM | #35 |
Lieutenant General
609
Rep 10,407
Posts |
^ Nice way to end a very lively thread. Talk real tech and ask for money. No better way to KILL a thread. This is quite funny to me.
|
Appreciate
0
|
07-31-2008, 05:15 PM | #36 | |
Colonel
99
Rep 2,000
Posts |
Quote:
Next round of data begins when the CTS-V hits the streets. I personally would like to have a handle on all this, because I think one of these types of transmissions will eventually lure me over to the dark side of two-pedal driving. I'm willing to wait, however. Bruce Edit: PS - Not that I'm particularly interested in starting another grumbling back-and-forth between us, but you're not the right guy to do this test, anyway. I know you pride yourself on objectivity, but your obvious bias has shown up in this thread and others. You know - things like accusing folks of bias if they have anything less than positive to say about the M-DCT box, etc. 2nd edit: OK, lucid's right. I take that last back. Last edited by bruce.augenstein@comcast.; 07-31-2008 at 05:54 PM.. Reason: That lucid guy |
|
Appreciate
0
|
07-31-2008, 05:39 PM | #37 |
Major General
374
Rep 8,033
Posts |
Bruce, it is clear that Swamp really likes his DCT, and maybe gets a bit carried away with his excitement for it at times, but when it comes to collecting and posting raw data, I am sure that he would do the right thing (I am sure you would as well). Interpretation of the data is another matter, and then we might all have disagreements depending on how clean the data are, and biases can play into that as they always do—happens in scientific/academic circles all the time. So, I don't see a problem with setting up a collective pot to do some testing around here. I doubt the mags will do the kind of testing we would like as the results would not have any significant implications for their broader audience.
__________________
|
Appreciate
0
|
07-31-2008, 05:50 PM | #38 | |
Colonel
99
Rep 2,000
Posts |
Quote:
|
|
Appreciate
0
|
07-31-2008, 06:01 PM | #39 |
Major General
1109
Rep 8,014
Posts |
I personally don't see the point in such an exercise, though if it was carried out my curiousity would be pricked a little.
My point is, we all know it's zero lose in momentum, every manufacturer says as much and it's exact how it feels when driving it. There's also numerous videos on Youtube between GTi Golf with and without DSG racing and you see each and every gear shift the DSG car pulls yards out of the manual. If it proved to be 6ms or 30ms, would such a thing make or break someone buying it. Somehow I doubt it. |
Appreciate
0
|
07-31-2008, 06:33 PM | #40 |
Brigadier General
532
Rep 4,021
Posts
Drives: 2008 335xi Coupe
Join Date: Feb 2007
Location: The land where we kill baby seals
|
Somebody buy this.... Does the iPhone accelerometer have the resolution to measure what we want?
http://dynolicious.com/index.html
__________________
"Aerodynamics are for people who cannot build engines"......Enzo Ferrari
|
Appreciate
0
|
07-31-2008, 07:55 PM | #41 | |
Dr. Octagon
260
Rep 1,919
Posts |
Quote:
PM me the type you are looking at/would like to use.
__________________
OC ///M
2013 E92 M3 Individual Sold: 2011 E92 M3 SSII | Sold: 2008 E92 M3 SSII | Into a Wall: 2008 E92 M3 SSII | Sold: 2007 E92 335i JB |
|
Appreciate
0
|
07-31-2008, 11:51 PM | #42 | |
Lieutenant General
609
Rep 10,407
Posts |
Quote:
2. Your bias against me is clearly evident and offensive. I would probably be THE best guy here to do testing like this. Nice try to take your words back but still really lame in the end. Why is it that you just can not believe that to me the truth and understanding are infinitely more important than brands and loyalty. You just do not know me, not yet, not after all of our banter, not one iota. Thanks lucid! OC: We need at least 500 Hz capability and DC capability as well. The accels and data acquisition system both have to be capable at this frequency. Foot: There is a loss in momentum with a DC, just really small (i.e. it is not zero loss). |
|
Appreciate
0
|
08-01-2008, 12:31 AM | #43 | |
Private
11
Rep 91
Posts |
Quote:
A better way would be to use a track data acquisition system such as a Traqmate or G2X which would store the data and allow later analysis and viewing. I have a G2X, it appears that the sampling rate is about 100Hz. I've attached two screenshots which show my data traces around an upshift. The Laguna one is in my GT3 (MT, not rushing), the Sears one is in my E46 M3 with SMG. Red line is engine RPMs, blue line is speed as measured by GPS, and green is longitudinal (acceleration G's). [oops, didn't realize the pix don't show the filenames, Laguna is the top one with a "3" in the window tab near the top center, the Sears SMG one is the one with a "10"] I think by looking at the shape of the green line, we might get a better idea, the resolution should be enough to get a better idea and comparison of MT vs DCT. Maybe not high enough resolution to accurately measure if the shift is 6 or 30ms though? But perhaps getting some data recorded with one of these might provide some insights.
__________________
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
|
08-01-2008, 01:57 AM | #44 | |
Major General
1109
Rep 8,014
Posts |
Quote:
To quote from BMW's own press release 'The M-DCT transmission with Drivelogic shifts gears without the slightest interruption in the flow of power', zero lose in power means zero lose in forward momentum. You can't preach one part of the press release to me (how the surge was created) and disregard the rest just because you disagree with it. If you prove there is a lose in momentum then that proves that what BMW wrote was wrong, and that might include the rest of their release (surge) as well. |
|
Appreciate
0
|
Post Reply |
Bookmarks |
|
|