I used a 6 inch 12v fan on mine. I am not sure what the cfm is but the fan has decent pitch in the blades and sounds like it is moving a bunch of air. Mine is mounted directly to the brush cover on the etek. I would like to use an 8 or 10 inch with a duct around the whole motor. I would like to know which direction the internal fan is moving the air as to not conflict with it.
I imagine the fan is connected to the spinny parts inside so it probably depends on which direction you're running the motor. I remember seeing a photo online someplace of an Etek that was taken apart. Anyone seen anything else like that? It would probably answer Paul's question.
Mike -- The Electric Motorcycle Portal http://www.electricmotorcycles.net/ Electric Motorcycle Listserv http://www.electricmotorcycles.net/listserv
