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2010 2011 BMW 5 Series Forum F10 Downshifting on its own while on semi-auto |
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03-05-2014, 03:29 AM | #1 |
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Downshifting on its own while on semi-auto
Hi everyone
This is a bit of a newb question probably, but I can't seem to find much about it online... I drive an f10 530d in India. I'm quite confused about something - While using semi-auto (paddleshifts or the shifter) on any mode (Sport/Comfort or even Eco Pro), if I slow down the car it automatically downshifts to usually the 2nd gear on its own no matter which gear I was on. Is there any way to stop this from happening and controlling it myself? This is quite annoying in India because its full of goddamned speedbreakers everywhere, and they always make my car change to a lower gear... Also, I lose track of which gear I am on and have to look at the screen everytime I brake to know which lower gear it has shifted me on to (usually its 2nd though) Thanks for your views on this! |
03-05-2014, 06:05 AM | #2 |
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I tihnk what you are seeing is the gearbox just protecting the engine and / or ensuring the engine is within valid parameters.
So it won't let you select a gear that causes the engine revs to be too high or to put a strain or labour the engine. Altohugh I not one for ussing the flappy paddles much, when I have used them, which gear the car was in made sense at the time. |
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03-05-2014, 06:19 AM | #3 |
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^^^^
As above. If you don't change down manually, then the software will do it itself, it has to. Clearly the way we use the auto makes a difference, if the stick is in M/S position and we are on the paddles, then the change point/rpm is lower for down changes (as low as it can go) compared to being in full auto where the revs will typically be a bit higher for down changes. It has been like this from the first 5-speed steptronic days, so nothing wrong in gearbox performance. BTW, what sort of revs are you talking of? My car will typically drop to ~1,000rpm for the forced down changes, which is no problem whatsoever. HighlandPete |
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03-05-2014, 09:01 AM | #4 |
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^^ exactly what these guys said.
The car can not be in certain gears if it is going too slow or too fast. You will either stall the motor or damage it by over revving. This is why the transmission will up or down shift to the appropriate gear based on your speed and driving style. Alan
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03-05-2014, 09:06 AM | #5 |
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Perfectly normal - just the way the gearbox works. Is it annoying? Not so much to me... I rarely use the manual mode, and I understand why the car is doing this... essentially to make sure you're in a proper gear for the speed you're traveling. While it has a manual mode, essentially it's still an auto, so it intervenes to "assist" whether you like it or not.
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03-05-2014, 09:19 AM | #6 |
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I was driving a manual car the other day with gear change indication. I was surprised that it sometimes recommended a down change at engine speeds and engine loadings I see as totally appropriate, for the gear I was in.
What we don't always understand, best fuel/emission mapping may not coincide with the lowest engine rpm. Even fuel economy can be mapped to be better slightly up the rev range. The torque curve can often help us see why this is so, a few more revs can put us in a much more efficient part of the BSFC (Brake Specific Fuel Consumption) mapping. Therefore the auto gives a good feel for what the designers see as optimum revs in a given situation, even at lower revs. HighlandPete |
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03-05-2014, 10:34 AM | #7 |
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In manual, it doesn't downshift until close about 1000rpm.
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03-05-2014, 03:07 PM | #8 |
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Rarely use the paddles as the 8 speed automatic and sport mose on car/gearbox are telepathic!
Generally use them for increased engine braking when in comfort mode or tight corners when again in comfort mode and want more control
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