Ok, I hear what you guys are saying.
But something else.
For a electrical fan to work, it must draw power from either the battery or the altenator.
If the battery drops in power the altenator charges it.
If it pulls power from the altenator,well, the altenator will charge all the time.
I have noticed that a altenator can draw quite alot of power from the engine.
So it is a lose, lose situation.
I would say leave the mechanical fan.
The gains will not be high enough for the conversion, unless you want less engine noise.