Actually the electric fans in the Taurus with the 3.8L engines push more air than any other aftermarket electric fan you could find else where. It is also the same fan used in the Ford MachVIII, which is also known to have the most powerful electric fan you can find. Remember too, I pulled my fan out of a '95 Taurus that probably saw most of its life in the heat of the Dallas area. They don't last forever. Once I put a new motor in it it will be just as reliable as any other aftermarket fan.
As the alternator ODP (over drive pulley). No it will not cancel out gains from the crank shaft UDP (under drive pulley). Unlike the rest of the front engine accessories, increasing the speed of the alternator does not increase the rotation resistance. The rotational resistance in the alternator only increases with more amperes are being drawn from the alternator.
MrQ is partially correct. To over drive the alternator, I will be replacing the pulley for one of smaller diameter.
To under drive the crank pulley is to decrease the diameter and to under drive the accessory pulleys would be to increase the diameter.
To over drive the crank pulley is to increase the diameter and to over drive the accessory pulleys would be to decrease the diameter.
I know it is a little confusing. But if you think for a while about it, you'll arrive at the same conclusion.