[Schon]

i just wanted to make sure that my logic makes sense. when you buy and install better drivetrain parts like lighter shaft. underdrive pulleys, fly wheel etc. these dont ADD hp or torqe but more like "free" it up right? thus making the rwhp number get closer to the bhp number . theres a less drivtrain loss(usually 13-15%) right? so these bascially make that percentage smaller?

 

[jep23]

That's the general idea. I'm not sure how close you can possibly get though. There will always be some loss

 

[Brutal Metal]

Even with an aluminum driveshaft, pulleys etc.. your gonna have double digit % drivetrain loss on the dyno from the Flywheel to the rear!

 

[racin366]

You've got it basically right, as above, there will always be some losses due to friction, inertia, etc, but those mods do "free up" some power. Only mods that change the engine's volumetric or thermal efficiency, or the way it uses the fuel create more power.