Quote:
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Originally Posted by CanAutM3
Quote:
Originally Posted by Boss330
The MT 6 did the 1/4 mile in 12,3s while most DCT cars have been around 12,1s IIRC. That is only 2/10ths of a second difference. Would that be good for a few MPH extra?
Or am I missing your point here?
EDIT:
Since the car doesn't stop during a shift but keeps rolling towards the finish line, the 0,2s difference, doesn't necessarily mean it spends just 0,2s less time accelerating. A average manual shift is probably around 0,3-0,4s.
R&T compared a MT with a paddle shift and found that each gear change took 0,37s on average (in that car) and dropped 0,9MPH on the paddle shifted car.
http://www.roadandtrack.com/go/news/...hift-gearboxes |
Let me try to explain my point with an example:
Let's assume that, as you stated, the DCT equipped M4 is 0.2 sec faster through the quarter mile compared to the 6MT, so the DCT has 0.2 sec LESS time to accelerate.
However, since the manual car needs to shift twice over the quarter mile run, it stops accelerating twice for a period of 0.3~0.4 sec each (the time it takes to execute the shift). The DCT does not stop accelerating during the shifts so it gains back 0.6~0.8 sec of acceleration time.
According to the R&T article, the 6MT M4 needs 2.1 sec to accelerate from 110 to 120mph. Hence the 0.4~0,6 sec of additional acceleration time that the DCT gets is worth 2~3mph.
It is that additional speed that allows the DCT to cross the line 0.2 sec before the 6MT... (that 0,2 sec at 117mph is worth about 30 feet, that is considerable). |
Great explanation of a very simple concept (it must have been my day off
).
This also points to one other significant advantage that needs to be accounted for when using simple trap speed calculators online. I'm not sure they are set up for 80ms shift times...?
IIRC the OP didn't want to share which shift times they used in their simulation... That is a point I haven't really thought to much about, but it might be a factor that will influence simulation results.