Underdrive pulley charging problems
Underdrive pulley charging problems okay so i just bought my first LS and im already having some problems. The previous owner installed a set of underdrive pulleys both crank and a smaller alternator pulley. It charges fine when not using any accessories but even when using the headlights they dim and the battery voltage gauge will drop. I hate having to constantly keep an eye on the battery gauge. would a 145a truck alternator do the trick? buy a set of stock pulleys? Bump up the idle? Its an a4 with a cheatr cam and idles at 550 rpm in drive. thanks for any advice
Last edited by camaroman101; Oct 25, 2014 at 08:42 PM.
while what you say is correct wouldnt a crank pulley still cause more drag and drain on an a4 car even with an alternator pulley?
ive always thought autos didnt benefit from an alt pulley? i dont have one on my car.
I thought autos were supposed to used the alt pulley as we have a lower idle rpm. Should i be worried about breaking the timing chain with the ud pulley or is that just for guys who road race? its an slp pulley
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From: Turnin' Wrenches Infractions: 005
Yes, autos idle at 550 in gear. By reducing that with an UD pulley the alt will have a hard time keeping up under high load situations like AC and lights. OP, does a blip of the throttle make your voltage jump to normal? If it does you may just need the smaller alt pulley that returns it to normal speed. Due to the heavy AC use here in the south I went with the alt pulley right from the beginning and have not had any issues. WS6store has the pulley and belt you will need.
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What are you guys considering as low output? What is the gauge reading? My car has been having problems with holding a charge and the voltage gauge only reads 13v when running and will go a little below sometimes also. Rpm does not seem to make mine any better either. I have UD crank pulley also. I am wondering if my alternator is starting to go bad
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My buddy had the same issue. He took off the f body alternator and bought one for a escalade and issue was fixed. I guess the escalade alternator puts out more power than the f body alternator do.
Joined: Aug 2007
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From: Turnin' Wrenches Infractions: 005
What are you guys considering as low output? What is the gauge reading? My car has been having problems with holding a charge and the voltage gauge only reads 13v when running and will go a little below sometimes also. Rpm does not seem to make mine any better either. I have UD crank pulley also. I am wondering if my alternator is starting to go bad
