Will I need a bigger alternator

Discussion in 'Electrical Systems' started by muscl car, Oct 30, 2017.

  1. muscl car

    muscl car Veteran Member Lifetime Gold Member

    I'm running the stock alternator and want to run an electric fan set up .I'm also running a MSD 7AL2 box that pulls 14amps . I'm also wanting to run a Magnafuel Pro series electric pump that pulls also 14 amps
  2. Fbird

    Fbird Veteran Member Lifetime Gold Member

    Feb 12, 2011
    atlanta, ga
    stock...?... 62 amp MAX
    Carburated? Street car (with headlights n stuff)?
    MORE = better ...lol
    an easy 100 amp upgrade would ideal FOR A STREET car! 62 amps don't leave much for rest of the car (ie battery) with lights and a stereo... in the rain...and the heater on ;)
    If you have room, i am a BIG FAN (no pun there..) of the 200 amp 12SI STOCK Caprice cop car (HD) alternator.
  3. muscl car

    muscl car Veteran Member Lifetime Gold Member

    This is a street driven drag race car and won't be running a serpentine set up , trying to keep same style alternator as stock but more amps . Besides what I've listed for amp draw I forgot to mention MSD 2 step , electric water pump and Transbrake also
  4. muscl car

    muscl car Veteran Member Lifetime Gold Member

    Trying to keep the car light , so the smaller / lighter the alternator the better
  5. Zspoiler

    Zspoiler Veteran Member

    May 6, 2012
    Federal Way, Washington
    Run one for an air conditioned car.
  6. Gary S

    Gary S Administrator Lifetime Gold Member

    Apr 14, 1999
    Bismarck, North Dakota
    Weight of the alternator won't be an issue. The more electric load you have the larger the altnernator you need (amps, not weight). The bigger issue will be the added horsepower the larger alternator takes to turn it. That will affect you more than the tiny difference in weight if may have.
  7. 74BIBELOT

    74BIBELOT Veteran Member

    218B4967-F21C-4DEA-960D-5534AE604DD8.jpeg You can try one of these.
  8. Turbo70Camaro

    Turbo70Camaro Veteran Member Gold Member

    Jan 7, 2005
    so cal
    Chuck just add all the components amperage and then add another 20-40 amps and buy the appropriate alternator.
    muscl car likes this.
  9. Joekool

    Joekool Veteran Member

    Feb 4, 2002
    Hollister CA USA
    If you're running a standard v-belt, you wont see anywhere near max potential amperage at idle or off idle. V-belts suck and will slip very easily when the alt is under load. I had that problem when trying to run a 100amp alt, I was able to get ~40amps at idle and the belt would glaze easily which lead to noise and even more slipping.

    The stock 120amp alt my LT1 has easily pumps out 75amps at idle and doesn't cause any problems with the serp belt.

    Just food for thought, higher amperage isn't always better if the belt setup cant support it.
  10. muscl car

    muscl car Veteran Member Lifetime Gold Member

    This is a drag race set up !!

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