I'm wanting to do the Taurus fan conversion many members have done, but I'm curious as to what amperage alternator I should get in order to keep up. the tech article on the site doesn't specify. Shall I assume I need an alternator capable of 130 amps like the Taurus came with?
With engine idling, measure battery voltage with the fan running, lights on and heater blower on high, if it doesn't fall below 12.4v you're OK... If it does, cut blower on low and measure again... My guess is that alt will handle the lights and fan while at idle at the least.. Even if it won't, bringing up the idle speed surely will give enough charge...
Back when I used alternator testing equipment we tested them "off idle". I understood that to be around 1000 to 2k rpm's. I am thinking that Powermaster you have at 107 should be enough. Just make sure the wires are good.
When I first installed my Taurus fan my 80 amp alternator didn't cut it. You need to figure out your worst case current draw for the whole car. Night time, all your lights are on, brake lights on, heat or A/C, stereo, aftermarket ignition(?), etc. Then on top of that the 40 amp Tarus fan turns on while your sitting at a stop light idling. Remember, an alternator's current rating is it's max output at some elevated rpm, not what it puts out at idle. I ended up going with a 150 amp 3G.
I have a 100A alternator with Taurus fan, Halogen headlights, and MSD 6AL ignition and no problems (in that area). Edit: Should add that the engine idles at 900 RPM in gear.
