dc2GS-R
Super Moderator
There are regular aftermarket pulleys that just reduce rotating weight. The underdrive pulleys reduce weight and are slightly smaller in diameter which spins the power steering, a/c, etc. a little slower reducing parasitic lossesKuchtaboy said:the purpose for an aftermarket underdrive pulley is for less weight, the A/C pulley is added weight you don't need if you don't have A/C