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07-31-2007, 04:05 PM | #1 |
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Why is BMW going away from SMG? Why does the press/others dislike SMG, but Love DSG?
I don't understand why the press & others don't love the SMG? I test drove an M3 one a year ago & I absolutely LOVED it!!! The 2006 M brochure says in the most aggressive setting (S6) it has 80-millisecond shifts, isn't that faster than Ferraris 100-milliseconds? In fairness I've never driven a DSG, is it that much better?
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07-31-2007, 04:54 PM | #2 |
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DSG uses twin clutches, one on the even gears, the other on the odd gears, and is optimized for upshifting under power. Upshifts take 8 ms. Down shifts, 600 ms.
http://www.autozine.org/technical_sc...ear_manual.htm |
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07-31-2007, 05:03 PM | #3 | |
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07-31-2007, 05:24 PM | #4 |
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Because SMG is hard to shift smoothly. DSG will have the smoothness of a slushbox, but with the benefit of lighting fast, controllable shifts.
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07-31-2007, 05:35 PM | #5 | |
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SMG vs. DCT
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07-31-2007, 05:37 PM | #6 | |
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Down shifts
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07-31-2007, 05:48 PM | #7 | |
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07-31-2007, 07:45 PM | #8 | |
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Yikes: "Changing down a few gears could be more complicated. The most complicated is from 6th to 2nd (both are controlled by the same clutch while the distance between the two gears is the longest). It needs to change to 5th (controlled by another clutch) temporarily before 2nd is selected. This takes 900ms."
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07-31-2007, 07:58 PM | #9 | |
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07-31-2007, 08:00 PM | #10 | |
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07-31-2007, 08:02 PM | #11 |
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Because DCT is FTW and SMG is FTL.
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07-31-2007, 08:03 PM | #12 |
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In my opinion SMG systems were basically prototypes for what we are getting now with the MDCT/DSG.
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07-31-2007, 08:30 PM | #13 |
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Exactly. If you are going fast enough to warrant 6th gear, you wouldn't then downshift to 2nd gear in 8ms anyway, without over-revving it. Ideally you downshift thru every gear on the track. A more likely track situation would be topping out 4th gear, braking hard, and while you're braking you go thru 3rd, then 2nd.... Not 6th to 2nd...
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07-31-2007, 08:59 PM | #14 |
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How'd I know someone would bring that up? Leave it to you nonetheless.
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07-31-2007, 09:02 PM | #15 | |
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07-31-2007, 09:26 PM | #16 | |
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Agreed. 6-2 might take some justification, but a 4-2 is pretty normal in everyday driving. The throttle blip adds a bit more time in these situations. This appears to be one situation in which the "regenerative" braking is counter-intuitive. |
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07-31-2007, 10:23 PM | #17 | |
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With heel-toe braking? Forget about it. That's where DCT/SMG shine. |
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08-01-2007, 12:40 AM | #18 |
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It is not clear yet wich system should prevail, in Garching they said both, SMG and DSG, are curently being tested. It could be possible that BMW keeps both, but as I said, nothing is sure for now.......................we will have to wait en see..............................
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08-01-2007, 12:49 AM | #19 | |
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Seems like M-DCT for sure
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08-01-2007, 01:40 AM | #20 | |
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I have had both a SMG and a DSG fitted car. My M3 with SMG was great and I loved every minute of driving it! My TT with DSG plain and simply sucked big time! I also can’t understand why the DSG system gets such good reviews. I am confident that the new BMW system will be good.
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08-01-2007, 02:53 AM | #21 | |
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08-01-2007, 05:45 AM | #22 | |
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This highlights the dangers of both car reviews and short test drives. I guess the DSG gets rave reviews because it is so versatile, the SMG on the other hand is bad in auto mode (which I never used). I assume that the M division won’t make a box that is not suited to an M car. A friend of mine bought his wife a SMG M3 and she absolutely hated it. When I attended the M high speed driving course my instructor loved the SMG. I also want the M-dct, but because I am high on the list I will take a Mt for now. I hope my coments helped.
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