Here's a question

[MEANMCHN]

Always wondered how the percentage got drawn up for Crank to Wheel HP/TQ.

Kenne Bell says to divide by .85, some say (in Jeremy Clarkson voice) that's it's 17% drivetrain loss for manuals, XX% for auto.

But doesn't it just take XX HP/TQ to get the vehicle moving.

For instance, if a Mustang makes 300HP and a similar one makes 1000HP and you base it on Kenne Bell's site the 300HP car actually makes 352 and the 1000HP car actually makes 1176. I've always wondered why/how turning over a same or similar drivetrain costs so much more power.

Discuss.

[HyperGT]

Takes power to make power. % of drag (parasitic loss) does not change just because you make more power. Its loss due to friction of drivetrain, rotating mass etc so should in theory be a %, in reality it is not perfectly linear....some losses may be more static but most are proportional, at least that is how i understand it. Divide by .85 gets you to the whole, newer cars are far more efficient and likely closer to 10-12% loss. I am sure someone will chime in with a more technical response.

[tulowd]

seems to be dependent on which type of dyno you run the car on as well. Eddy current loads it up; inertia dyno reads rate of acceleration and calculates it.
Proper way would be engine dyno and then car dyno to compare.
I imagine an auto sucks up more power due to the torque converter than a manual / clutched trans. Rear end will be the same, likely higher losses with a higher gear ratio.