Alternator Question

Discussion in '1996 - 2004 SN95 Mustang -General/Talk-' started by m0squ1t0, Oct 19, 2013.

  1. My 2002 Gt is not keeping charge due to my steeda UDPs. I was told I need a higher amp alternator to compensate. What size is stock? What size do I need? I don't have anything crazy in my car, no amps subs etc... Thanks!!
  2. Anyone? I really need some direction...I have found out that the stock alternator is 110 amps so I need to know what size to replace it with to avoid having the battery drain on me.
  3. The PA alternator are 130 amps. What specific issues are you having now?
  4. My opinion is that under drive pulleys are a joke. I have ran them and they just cause overheating problems
  5. Has the alternator been tested to ensure that it is operating correctly? Could just be a case of an alternator going bad.
  6. the battery and the alternator have both been tested. I was told both are good. I was also informed that the underdrive pulleys are causing the alternator to not properly charge the battery enough because if I sit at a red light while its raining with my radio, lights and windshield wipers on the battery gauge drops unless I rev my engine in neutral. I don't have anything crazy in my car I have a replacement deck with the factory equivalent speakers.I've never had any overheating problems.
  7. Maybe try putting the stock pulleys back on and see if that fixes it. If it does, I would weigh the advantages of underdriven pulleys versus having to fix the issue. I had pulleys before my blower install. I was not impressed by any change they made.
  8. Stock pullies are a no go. Car came with the UDP system.. This is a problem that is new not something that has been around...could this be a programming issue?
  9. While the alt and battery my have tested OK I'm betting they are at the minimums. I had UD pullies on my old car and had frequent power issues. I eventually did away with them.
  10. I don't have thoriginal pullies, so for now thats a no go. Could i go with a higher amp alternator?
  11. Higher amp alternators are not the cure because they still require a minimum RPM in order to create power.

    The issue here is that your current alternator is spinning too slowly to produce a proper charge. Going to a higher amp alternator may not fix the issue of your accessory belt is still spinning too slowly to fix that issue.

    You have 2 solutions:

    1) find a set of stock pulleys and swap them back on

    2) Find a stock alt pulley, or an aftermarket alt pulley that will fit of larger diameter in order to OVERDRIVE the alternator and compensate for the slowed down accessory system.

    A 3rd option is to find an aftermarket alternator that produces full power at a lower RPM than stock. You'd need to know crank pulley size and alt pulley size and do a little bit of math to calculate if this will work.

    Option 1 is prob the easiest