http://www.rctech.net/forum/electric...less-dyno.html

Look at the graphs at the beginning of this thread.
Peak wattage properly measured is typically encountered halfway to the max RPMs of the motor, and under extreme exertion (dyno measurements are the motor turning a flywheel with full throttle). It can take 6-7 seconds for that flywheel to get up to speed whereas a typical RC brushless setup gets up to speed in 1.5 to 3 seconds or less.

In reality, for brushless, modified racing or bashing, it's basically an irrelevant number with no real bearing on performance. Manufacturers themselves have no idea how to rate their motors, since a modern 1/10th scale brushless modified motor can pull more than a thousand watts if the conditions are right. So honestly they are just pulling numbers out of their #$$ and putting them out there.

Don't get overly involved with the numbers, staticians don't do too well in this hobby (or in many others).

I remember playing 'ball this weekend and there was one guy telling me how his matrix (newer) did 18bps and mine (a few years old) was only 15bps rated and my friends A-5 was only good for 13bps and that was only with the e-trigger that he didn't even have... so his must be superior and I just started rolling my eyes and thought 'not another one of these guys... why do they always end up being on my team...' It's no different than the guys who buy cameras based on megapixels or the guys who buy computers based on clock speeds, it's become something of an arbitrary number that has only a peripheral bearing on the quality of the setup.

Basically, if you are going to talk theory, always have a problem in mind that you are trying to solve; don't overthink things. There's a lot of things that don't really make perfect sense in this hobby, just the way it is.