the main belt tensenor is reverse thread, the supercharger belt tensenor is regular thread.

my lower idler pulley for my supercharger was squeaking, pulled it off and there is a little bushing that fits inbetween the bolt and the bearing on the pulley (it takes up the slack, the bolt is not the same size as the bearing and with out the bushing the pulley can slop around) that bushing was not in right, once i put it back together it stoped squeaking.