Ok, you have three pullies.
The crank pulley is smaller, so it turns all of your accessories slower. The Water Pump and Alt pullies are bigger so they turn their respective accessories slower. Hence, everything is underdriven. You get best effect from using all three, but you can use any combination of stock and U/D pullies you want, but you might have to go to a different belt, I'm not too sure on that one.
When you U/D the Water pump, it pumps slower, and will cause the car to run a little warmer. When you U/D the alt, it isn't putting out as much juice, and doesn't charge the battery as well. Make sense now?
B Team - More skill, more results. A is only a starting point before progressing to B.
Member of the 'B-Team'. Finishing jobs the 'A-Team' can't handle.