always heard your not supposed to run a underdrive pulley that is smaller than stock when running a higher output alt. is that going to be a problem if i put the rrm pulley on the car with my excessive amperage 180 amp alt? thanks guys i guess this should be in sound section but i just was here and figured eh why not.

 

well at idle you should still have about 13.8-14.2 V charging.....even with UDP. At higher RPMs it will of course rise.....I don't really see at problem.....since it looks like from your sig that you are running 2 12" subs. Even with the higher output Alt it will still put a strain on your alt but will not put as much as stock. Stereo systems lessen the life of the Alt no matter the output campared to stock system. Either way i do not really think there will be any problem other then still having the lights dim alittle at idle.......hope this helped...

 

lights dimming with UDP of course...