i just got a set of underdrives for my car and noticed that the stock water pump pully is smaller than the underdrive...i thought that all the underdrives were small in dia. than the stock pullies.am i right or wrong?
new crank pulley should be smaller and new water pump pulley should be larger. The under drive pullies slow your accessories down to reduce parasitic drag. basicly free up power yuor car already makes. I used to run race pullies before my supercharger went on. now i have an over/under crank pulley.