less rotating mass (lighter pulley, less belt) = better responsiveness of engine
less friction/resistance to rotation (smaller diameter pulley, shorter belt - less surface contact for friction) = more horsepower
unknown - how accessories respond to different rpm - resistance to rotation may increase with rpm, or may decrease. ultimately, however, if the accessories output less when turning slower, all while still meeting the needs of the automobile, less unnecessary work is getting done. less work over time means less parasitic horsepower loss.
|