@Art and lucid: There is much interest in a greater resoultion of the accleration profile during the shift and hence you need many sample points across the event. 300 Hz is marginal given Nyquist to capture a great deal of the actual dynamics during the shift. I think longer term, if shifts get much quicker than 30 ms 500 Hz would be a good sampling to stick with. I am not very interested in the frequency content myself, enlighten me.
Quote:
Originally Posted by e46e92love
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......
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D3 is shifting faster by design. When it comes to perception the shortness is directly related to the smoothness. You can not add any appreciable change in velocity if the duration is incredibly short, again ΔV = a x t, if goes to zero so does ΔV. In the extreme who cares if a shift is slurred across 10 seconds if the acceleration were actually higher than during the non shifting period. Very likely non physical here but you get the point.
D modes are:
-Mathematically more jerk (surge)
-Psychologically smooth and very little surge
-Very short in duration
S modes (S4->S6, i.e. those that have surge) are:
-Mathematically less jerk (surge)
-Psychologically rough with great surge
-Significantly longer in duration
It is slightly contradictory, S4->S6 FEEL faster but aren't. The exact same phenomena happens with the shape of cars torque curve. Lumpy/peaky can feel fast but not be as fast.