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Discussion Starter #1
Hi guys and ladies for the few of you. I just got a set of underdrives for 40 bucks stuck them on. My alt is now all messed up. Its reading 12 volts at idle i know my truck idles realy low. Around 650 to 700. Anyone else running these pulleys? Have the same problems? Would a suburbun alt work better on this. The amps should be higher I'm guessing. Thanks for your help. All yeah i need to get it fixed i got a set of e fans to go on. They will kill my alt at low idles thanks.
 

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HOT AIR BALLOON OWNER
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14,932 Posts
Buy an overdrive alternator pulley, this will speed it back up at low RPM.

If you're planning efans too, you need a larger alternator AND the OD alt pulley.
 

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HOT AIR BALLOON OWNER
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I got the bigger alt pulley still dont seem right it kills the battery at lower speeds thanks


OVERdrive alt pulley dude, not underdrive. Underdrive for alt is larger, overdrive is smaller
 

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HOT AIR BALLOON OWNER
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14,932 Posts
so what i can just put the stock on back on and that should help out?


Stock alt pulley? Yes. Go with a 1-3/4", I used to distribute for ASP Pulleys. Just call them and tell them you want an OVERDRIVE alt pulley for your truck. Talk to Candice or Lee there.

Scope the link Chris gave you, you'll need a bigger alt when /if you do efans as the accessories are already slowed down.
 
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