A simple example. 100 * 80% = 80. 80/100 = 80%. 80 * 1.20 = 96! 80 * 1.25 = 100. It takes a higher percentage of a smaller number to equal a smaller percentage of a larger number. It is easier to work from an estimated crank HP to arrive at a rwhp and recalculate.

310*.17=52.7 and 310-52.7=257.3. ZX is right. It is "drivetrain loss", not "rwhp gain to the crank through the drivetrain backwards" (or something).

 

I think ElvishasaZ's argument is "a lighter crank pulley is drivetrain loss reduction" rather than engine power addition.

So I disagree, the pulley sits on the other side of the drivetrain. If i'm not mistaken, if the engine was pulled and tested on a crank dyno, the gain would still apply.

I agree, however, that a flywheel just reduces drivetrain loss as it's a component of the drivetrain.

 

Obviously the pulley reduces loss in the system. It cannot add power. If that was the case, you could have a car with just pulleys and it would go.

Gas and Air make power. If the mod increases either, it can make power.

X