theworx

Does it make sense that the drivetrain loss would always be 25%? It doesn't really make sense to me. Drivetrain loss would be drivetrain loss. Why would you lose more power in the drivetrain with a more powerful engine.

You're saying that with 227 chp the whp is about 150 or so, about a 33% loss in power or 77hp. Now if that wrx was built up to 400 chp would the whp be 268 or 333? I think 333 makes more sense than 268.

What do you guys think? Is there a % loss or a predetermined hp loss independant of HP level?

Kevin M

iTrader: (12)

This is a debate that once raged all across the Subaru webring. Essentially, it isn't a static percentage of power, nor is it a static torque or horsepower number. that is why it is so hard to guesstimate drivetrain losses. That in turn is why you will see almost all horsepower figures in at-the-wheel horsepower. While dynos certainly have their differences, their measurements are still empirical data.

theworx

So the jury is still out on the matter.

Kevin M

iTrader: (12)

Not exactly. The verdict is that drivetrain loss is a potentially definable thing, just nobody involved has the ability to pin it down. Basically it would require several cars, a chassis dyno, and an engine dyno, along with several hundred hours of careful effort and analysis. Nobody cares enough to make this happen, so we stick to our guesstimates.