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03-27-2008, 03:48 PM | #133 |
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Around 90mph depending on which rear tires are on the car and how far into the "overrev" range I run it before shifting.
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03-27-2008, 04:02 PM | #134 |
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Nice thread.
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03-27-2008, 04:04 PM | #135 | |
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That being the case, we try to put all the information we have to try and guess what M-DCT will be like. My guesses: 1) Auto mode will be greatly improved. Much smoother than SMG. 2) Sequential/manual mode (or whatever they call it) will be better than SMG. It promises faster shifts and a little extra energy transfer on up-shifts. I've read that they still have the throttle blip on down-shifts. If it is anything like the SMG then it will be close to heaven. Just my $0.02.
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03-27-2008, 04:07 PM | #136 |
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Ha, did anyone else notice that the little mad guy smiley in my previous post looks like my new Avatar? Let's call that little mad guy Fil.
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03-27-2008, 04:21 PM | #137 | |
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Best regards, south
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03-27-2008, 04:55 PM | #138 |
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Swamp, South, guys, thanks for the very interesting thread. Those of us who have DCT cars coming soon will enjoy playing and learning about this fantastic car/trans combo. Thanks!
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03-27-2008, 05:04 PM | #139 | |
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M5 / M6s in North America are available with 6MT because some marketing knobs at BMWUSA thought it was a good idea. Now the 6MTs are collecting dust on the dealer lots. Here is a US M6 with SMG3. You can hear the chirp for awhile...
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03-27-2008, 05:17 PM | #140 | |
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I have read the entire thread including Enigma's accelerometer readings on his SMG2 M3. My ONLY area of contention with your estimates has always been your assumptions around shift times.
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03-27-2008, 05:27 PM | #141 | |
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This is not as bad as it seems as there are other cars like the M5/M6 or the GTR or the Bugatti (etc.) that only came/come in one flavor. It was like that until BMW made the 6MT for the M5s. I guess I want to make the best decision I can. I am leaning towards the DCT mainly b/c I didn't love the 6MT as much as I could. I plan to get another test drive on the 6MT soon if I can and then go by the process of elimination. but I'm keeping my eye on the net to see when there is a real (or better) review in the next few days hopefully. |
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03-27-2008, 05:35 PM | #142 | ||
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Read the reviews about DSG and the similar systems which have copied their design, in every case it is believed to be better than any single clutch system, so clearly Audi's engineering skills are not in question. If you were to say that BMW decided to give their version the M appeal which is the feel the shifts because it feels sportier then I could agree with that, but to think that Audi have decided after years of development and research that such a jerk/surge would benefit acceleration but choose not to use it is the dumbest of things I have ever heard. The Veyron would have benefited from such a setup if that had been the case but VAG didn't use it or even offer such a mode, the facts are that it didn't benefit acceleration and they decided not to go down that route. To believe that only BMW were right and Audi/VW/Bugatti were all wrong is the kind of arrogance that gives fellow BMW owners a bad name. |
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03-27-2008, 05:47 PM | #143 |
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Right, I calculated about 0.4 kph but you are right, not an enormous effect. Do recall that you have to regain everthing you loose just to get back to "even". This effect will be smaller on a little aerodynamic Elise comapared to other cars. That was a really fast shift as well, 0.25 seconds. I bet you can't shift that fast! Lastly this effect is much larger when shifting at higer speeds.
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03-27-2008, 05:48 PM | #144 | |
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Its really this simple, when a car shifts there is energy stored in the moving parts of the engine and flywheel. That HAS TO GO SOMEWHERE. BMW chose to use it for acceleration at the expense of smoothness. Audi chose to smooth the transition at the expense of wasting some stored energy. It really is that damn simple. I am sorry you are too dense to get it but I am tired of trying to explain this to you.
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03-27-2008, 05:54 PM | #145 | |
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As well my sketches do not show SMG III vs. II, I only show SMG but my numbers indicate something like the minimum shift times for SMG III. I still disagree with you on the other points as well. My x and y scales are likely not perfect and like enigma pointed out my acceleration post shift for DCT is very likely too high. These were just SKETCHES! That being said. I will bet that M-DCT at best will easily break 100 ms shift times. I won't bet on margins compared to SMG III as you wanted. Furthermore DCT can and almost for sure will phase the clutches to drastically reduce or eliminate the deceleration period. I will bet on drastically less deceleration than SMG (any variant) with the ability to not dip to negative as well. |
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03-27-2008, 05:58 PM | #146 | |
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Did you read the good post here about wheel spin/slip? Do you not think that a Veyron with a MT could break loose wildy in every gear? THINK ABOUT IT, PLEASE. |
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03-27-2008, 06:03 PM | #147 | |
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Didn't know it was Enigma's Elise....wow...good shifting! Hey if you put up sketches with a scales....you are inviting scruntiny. Name your wager
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03-27-2008, 06:04 PM | #148 | |
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You still aren't explaining why BMW and Audi quote an identical improvement over their manual cars. Surely if you were right BMW would be quoting an even bigger improvement but the facts are they aren't.............why? Maybe the difference is so small as to not make any noticeable difference at all and that is what the guys is meaning, who knows. Only when both systems are tested together will we see for sure. |
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03-27-2008, 06:14 PM | #149 | |
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Actually the system was developed by Porsche originally and latter refined for production by Audi in conjunction with Borg Warner. As for the Veyron, it was never an option for the Bugatti to get a manual, they always decided on DSG right at the early stages and it was one of the reasons why the car took so long to reach production. The Veyron only puts 200hp to the front wheels in normal hard accelerations, that means there is 800+hp going through the rears. Would this small surge that BMW have engineered in cause the car to break traction, I somehow doubt that, but then again we will never know because to choose not to offer it now did they. |
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03-27-2008, 06:22 PM | #150 | |
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03-27-2008, 06:23 PM | #151 |
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Feel free to keep believeing the marketing numbers and speak. I am sure if you asked BMW about their strut suspension they would tell you its great too. But we all know its not.
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03-27-2008, 06:27 PM | #152 | |
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1. M-DCT under its fastest shifts will exhibit shift times shorter than 100 ms as defined by the period in a sufficiently accurate accelerometer trace from the initial point of deceleration to the resumption of acceleration (sharp-ish knee after shift). 2. Such acceleration curves will dip substantially less than MT or SMG curves on deceleration and will be capable of exhibiting shifts where the dip in acceleration will not go to negative acceleration values. |
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03-27-2008, 06:29 PM | #153 |
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03-27-2008, 06:30 PM | #154 | |
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This is theoretical. I really don't know if M-DCT can do this. . I am assuming it will. But remember: in theory, theory and reality are always the same. In reality, they're not.
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