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Discussion Starter #1
Ok. I've got all my parts ready. I showed my EE friend all the parts, Chev-Hell's wiring diagram, and the one for a mark VIII with the 3 way switch. He examined all the stuff, and drew up a new wiring diagram using both of the prior diagrams, and we picked places on the car to mount stuff.
I've run into a problem though. I don't understand electrics, and he dosen't know much about electric systems on cars. He was using a mathematical formula to decide what guage wire to use depending on current, and things like that. He's fine with electrics.
I know the windstar unit takes about 36-40 amps. I have a rebuilt SI alternator that puts out 'atleast' 73 amps according to where I got it from. I have a stereo, and all sorts of normal road car stuff. I'm looking at a CS 105 or 124 alternator.
But I don't want to buy it if I don't have to. And neither of us know how to test if I am making enough power, and he suggested the only way he could think of is to install an ammeter (I have neither a ammeter or voltometer, but he has equipment to measure volts).
Is there an easier way to test and see if I am putting out enough amps to run this? Or do I need an ammeter?

Thanks alot,

Premium Member
5,063 Posts
Hook it all up as you want to.

Use his Volt-meter and clamp it to the battery terminals. It'll read 12-13Volts. Let's call this number the BASE Voltage.

Start the car.

It'll read 14-15 volts.

Now start to turn stuff on...

After swtiching on both fans, it'll drop suddenly to 10, then climb up to 12-13Volts when the alternator compensates for the load. milliseconds though.

If your battery reading is ever LESS than your BASE voltage the alternator isn't doing it's job and the battery is discharging.

Be sure the Alt will work with your bright-lights on, fan on, radio on, hazards on. You know, try and over work it.

You'll notice that as you load it with more electronics you may need to idle the motor up some. Moreso, if you rev it up the Alternator will be able to do more work, but this is actually masking a potentual problem.

71' 3880# with me. Big Block 402, Merlin oval heads, 10.2:1CR, TH400, 3.73 posi,
1/8th: 8.0 @ 88mph
BEST 60': 1.85 w/street tires.
BEST 1/4: 12.5 with 1.89 sixty foot (street tires)
BEST MPH: 109mph

Picture of me roasting the tires and other guy stuff
Video of me staging (smoke of course)
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