Quote:
Originally Posted by WWM
What does that have to do with them underrating the engine? The exact numbers are a mystery, but it's obvious that if it's dyno'ing 305/320 at the wheels then it's making more than 322/330 unless BMW has figured out how to achieve 5% drivetrain loss.
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My point is that it is
not obvious that a wheel dyno of 305/320 automatically means more than 322/330 at the crank. What kind of wheel dyno was that? Who ran it? What correction factors did they include? The purpose of a wheel dyno is to evaluate HP at the wheels for the purposes of tuning. Get a dyno baseline, tune, dyno, evaluate, repeat.
In order to accurately calculate crank HP using a wheel dyno, you have to have a very special kind of dyno that most shops don't have. They don't need to know crank HP; they only need to know if the tuning they're doing is improving the output of the car.