suby01 wrote:lol sorry i didnt follow that. pulley does make horsepower if its an underdrive pulley a stock diameter one will just free up used power. so while technically only on a dyno 1-2 hp will show up. the amount of power freed up is a lot more. so it does make power since now first gear im spinning all 4 tires.
Pulleys are either driving something or being driven. They do not create horsepower. What a properly designed pulley can do is reduce parasitic loads. This can be done by changing the turn ratios of what is being driven, by reduction in weight, and also parasitic loads caused by how the belt turns on the pulley itself. One does need to consider the normal engine rpm for a particular driver as you need to take in consideration of the needs of what is being driven and at what rpm is needed to match its needs.
Also dampening and balance needs to be maintained for benefit of the engine.
We used to prefer lightweight flywheels. This left your accessories unaffected at any speed and gave similar claimed benefits due to reduction in weight such as increased acceleration. Of course they don't look as pretty.
Perry
