Quote:
Originally Posted by coloradoe92m3
Gearing :
So check my math but 1st bear choice is crazy. I can't use 1st in my e92 due to traction limitations so talk about hard to launch. F80 will be really tough to put power down in first. 2nd gear is going to be downright freight train. But e92 is quite a bit shorter gearing from 2nd on.
So you can't only compare dyno plot as gears are the other half. If someone wants to create a plot with gear ratio differences taken in to account, the f80 will be way faster but not quite as much as it has seemed thus far.
Keep in mind at WOT you don't see below 6500 ROMs in e92 dct so you can't draw a line straight up as they do as you need to account for e92 power band .
So love to see area under curve of each cars WOT power band with gearing taken into account
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Here you go:
I agree with you, 1st gear will be pretty much useless for maximum acceleration due to traction limitations. I am guessing that such a short gearing is necessary to maintain drivability and decent acceleration in day-to-day puttering around when the engine is not on boost.
I also agree that comparing the two engines power charts as a function of RPM is pretty much useless because it does not factor in the gearing. I plotted the max available engine power vs road speed for DCT optioned F8X and E9X on the graph below. From 35mph to 155mph (2nd gear and up on the F8X), the F8X produces an average 423hp compared to the E9X that produces 391hp. That is 8% more (not considering any underrating of the S55). It is not negligible, but not as much as the graph in the interview leads one to believe.