100amp alt with EFI, fan, water pump...

Discussion in 'High Tech Retrofits' started by woody80z28, Oct 11, 2014.

  1. woody80z28

    woody80z28 Veteran Member Lifetime Gold Member

    Messages:
    5,608
    Likes Received:
    85
    Joined:
    Sep 8, 2004
    Location:
    walton, ny usa
    I put a 100amp alt on my car years and it's been great, even with a big fan and elec water pump. But now I'm doing Holley EFI, fuel pump, all elec gauges...and I'm wondering if 100amp will be enough.

    What are you guys running on your EFI cars?
     
  2. SHANE 73Z

    SHANE 73Z Veteran Member Lifetime Gold Member

    Messages:
    3,055
    Likes Received:
    0
    Joined:
    Feb 26, 2002
    Location:
    Meadow Lands, PA
    Hey Eric,

    I am still running a 100 amp CS130 in my truck now.

    At the moment I am running:
    - In-tank A1000
    - 16" Electric fan
    - Holley ECU/injector driver

    At the moment it ssems to be adequate. I am also currently conducting an experiment of running a 17lb Braille battery. Plenty of cranking amps so far, but the reserve capacity is marginal. If ever install a stereo or other items, I may need to upgrade.

    Shane
     
  3. SHANE 73Z

    SHANE 73Z Veteran Member Lifetime Gold Member

    Messages:
    3,055
    Likes Received:
    0
    Joined:
    Feb 26, 2002
    Location:
    Meadow Lands, PA
    Also,

    I dont know what you have for an accessory drive. But I was able to get a smaller then OE 6 rib pulley for the Alt. With the mild cam I can get the engine to idle down to about 600 rpm and the low speed charging suffered.

    Smaller pulley helped. If you are running a CS or SI it is currently off the car and I would be happy to send it to you if you wanted to try it.

    Take care,
    Shane
     
  4. TheMeat

    TheMeat Veteran Member

    Messages:
    970
    Likes Received:
    2
    Joined:
    Feb 9, 2007
    Location:
    Ol' Miss.
    145 amp on mine.

    Dual fans, PCM, stereo, dual fuel pumps, inter-cooler pump, HVAC, etc.

    I have the 'bastard child' truck accessory drive on my car so the high amp Denali, Escalade, Yukon factory alternator bolts right up.
     
  5. Randy 81

    Randy 81 Veteran Member

    Messages:
    938
    Likes Received:
    20
    Joined:
    Oct 28, 2009
    Location:
    Loganville, Ga
    My truck has a 92 454 TBI with a 100 CS style amp alt, works great. If it was enough for the 92 Suburban it was in with full power accessories, it should work for your car.
     
  6. woody80z28

    woody80z28 Veteran Member Lifetime Gold Member

    Messages:
    5,608
    Likes Received:
    85
    Joined:
    Sep 8, 2004
    Location:
    walton, ny usa
    I'll still be V-belts, and the car won't be back together for quite a while right now. It's on the rotisserie.

    But if a 92 only has a 100a, that's encouraging. Those didnt have an elec fan or water pump, but I also don't have a stereo or hvac.
     
  7. mrvedit

    mrvedit Veteran Member

    Messages:
    1,357
    Likes Received:
    4
    Joined:
    Jun 12, 2009
    Location:
    Ann Arbor, MI
    The Holley EFI probably doesn't use more than 5 Amps, the fuel pump 10 Amps and the gauges just 1 Amp. So you didn't add much.
    The bigger users are the electric fans (30 Amps) and headlights (about 15 Amps for all lights on). I don't know how much your electric water pump uses, but it might be in the 20 Amp range.
     
  8. Joekool

    Joekool Veteran Member

    Messages:
    5,922
    Likes Received:
    35
    Joined:
    Feb 4, 2002
    Location:
    Hollister CA USA
    The Alt might be rated at 100amps but what you need is to find out what it will actually put out at idle and off idle. Most Alts don't reach peak output until 2000 rpms or so.

    On most newer cars with all kinds of do-dads, at idle with all the big loads on (A/C w/blower on high, rear def, head lights, seat heaters etc) I tend to see at idle 70-90amps and 13.4-14.0 volts. Those are alts rated for 120-160amps
     
  9. woody80z28

    woody80z28 Veteran Member Lifetime Gold Member

    Messages:
    5,608
    Likes Received:
    85
    Joined:
    Sep 8, 2004
    Location:
    walton, ny usa
    Nah, the water pump only has a 5A fuse. And if I'm only adding another 16 or so I'd think that's ok.

    Will an alt put out more amps than are being used? I would think it wouldn't but I could be wrong.
     
  10. Joekool

    Joekool Veteran Member

    Messages:
    5,922
    Likes Received:
    35
    Joined:
    Feb 4, 2002
    Location:
    Hollister CA USA
    If the alt cant keep up the output voltage will drop to battery voltage, basically any current the alt cant supply will be pulled out of the battery. If this happens for too long the battery will discharge and the car stalls and you will be walking.
     

Share This Page