"Power" pulleys and alternator output... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ItsRandy · 07-22-2012, 06:11 PM

Anyone have any experience with aftermarket under-driven accessory drives effecting alternator output and cooling efficiency. My 100 amp alternator only charges 12.1-12.3 volts @idle and 12.8-13.1 volts @2000 rpm. The water temp is in the 195-215 range with a 180 deg. thermostat, 2 row 1.25" tube aluminium radiator the air conditioning on and 100 deg outside. I was thinking of changing my crank pulley from a 5.5" (under-driven) to a 7" (stock size) pulley. What do you guys think?

ItsRandy · 07-23-2012, 10:29 PM

ttt

colin_havens · 07-24-2012, 10:34 AM

I don't know if that will fix your problem, but I am no expert by any means. When I got my truck the previous owner had installed under drive pulleys, and it has never charged correctly or cooled quite like it should. After years of chasing these problems, I finally realized that it was the pulleys that caused my problems. In my opinion, under drive pulleys are for track cars, who need every last HP they can squeeze out of their motor. Mine stays on the street, and is a cruiser, so I ordered a March serpentine setup that is supposed to increase cooling and alternator output, but doesn't ad HP. I want reliability, not an extra 8-10 pines under the hood.

07-22-2012, 06:11 PM	#1
ItsRandy Registered User Join Date: Nov 2010 Location: Grand Terrace, Ca. Posts: 1,607	"Power" pulleys and alternator output... Anyone have any experience with aftermarket under-driven accessory drives effecting alternator output and cooling efficiency. My 100 amp alternator only charges 12.1-12.3 volts @idle and 12.8-13.1 volts @2000 rpm. The water temp is in the 195-215 range with a 180 deg. thermostat, 2 row 1.25" tube aluminium radiator the air conditioning on and 100 deg outside. I was thinking of changing my crank pulley from a 5.5" (under-driven) to a 7" (stock size) pulley. What do you guys think?

07-23-2012, 10:29 PM	#2
ItsRandy Registered User Join Date: Nov 2010 Location: Grand Terrace, Ca. Posts: 1,607	Re: "Power" pulleys and alternator output... ttt

07-24-2012, 10:34 AM	#3
colin_havens Registered User Join Date: Dec 2007 Location: Mountain Home, AR Posts: 405	Re: "Power" pulleys and alternator output... I don't know if that will fix your problem, but I am no expert by any means. When I got my truck the previous owner had installed under drive pulleys, and it has never charged correctly or cooled quite like it should. After years of chasing these problems, I finally realized that it was the pulleys that caused my problems. In my opinion, under drive pulleys are for track cars, who need every last HP they can squeeze out of their motor. Mine stays on the street, and is a cruiser, so I ordered a March serpentine setup that is supposed to increase cooling and alternator output, but doesn't ad HP. I want reliability, not an extra 8-10 pines under the hood.



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