Alternator Question

Electrical & Ignition

  1. 71newp

    71newp Well-Known Member

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    I have a '76 Cordoba that has a 60 amp alternator. I have heard that the wiring harnesses were "sized" to the alternator. If this is true would it be dangerous to upgrade to a 78amp alternator? My 60amp has a single groove pulley, the 78amp has a two groove pulley. Would this be an issue? Thanks
     
  2. PurpleBeeper

    PurpleBeeper Well-Known Member

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    That is a good question. I had a 77 Cordoba and I "think" it had a factory 100amp alternator (?). It wouldn't make sense to manufacture 3 different wiring harnesses for 3 different alternator options (or even 2) in the same car & hope the factory guys didn't mix up the harnesses. I would bet you're OK upgrading to any optional alternator for your year/make/model...but check & don't take my word on it.
     
  3. 493 Mike

    493 Mike FBBO Gold Member FBBO Gold Member

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    Check the existing alternator output wire gauge and look up ampere carrying capacities of automotive wiring for your answer. If necessary you can add a new larger wire to the battery from the alternator.
    Mike
     
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    • WileERobby

      WileERobby Well-Known Member

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      Why do you need to go to a 78 amp ? Are you adding lighting, audio, ..?
       
    • 71newp

      71newp Well-Known Member

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      The 78 amp is actually cheaper!!!
       
    • Nacho-RT74

      Nacho-RT74 Well-Known Member

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      And better!
       
    • ChargerM440

      ChargerM440 Well-Known Member

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      If you’re worried about increasing the size of your alternator the easiest thing to do is to add a larger gauge wire going from the alternator post directly to the pos side of the battery. You can use a wire calculator to determine the size you need depending on the total length. In this case I would run a dedicated 8 gauge wire with an in-line 90 amp fuse to the pos battery terminal.


      https://www.wirebarn.com/Wire-Calculator-_ep_41.html
       
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