On second read, I see your point. Perhaps my analysis is somewhat off. The alternator is on the circuit created by the battery and electronics. I suppose in that situation that everything is more of working in unison to send a solid charge to the whole system. Alternator feeds power to the battery pole, but that power may be pulled away from the pole before ever getting to the battery by some other electronic device, at the same time as in UPS systems, the battery is supplying or drawing power from the system to keep the power in the system level. This is why a dead battery will cause fluctuations in the power output of the system and why you get flickering lights.

I think it's more of a system working together from the battery and alternator than one or the other at any particular time when the engine is running.

 

How does all this affect the ignition--> the intensity of the spark?

 

I imagine the only spark issue is if you overload the system. I doubt anything but a really powerful and high-draw fan would effect spark. And you don't have to worry about the fan stalling or changing direction, remember that electric motors aren't physically connected to the output shaft, it uses magnetic fields. Now I would more worry about pulling heavy charge trying to overcome the outside forces, then if the fan does spin in reverse signifigantly, it could cause your motor to become a generator and all this could lead to blown fuses and other electrical gremlins.

 

To more elaborate on the spark, the ignition uses a particular input feed. As long as you don't drop below that input, you will get the same spark. An electrical device won't pull any more than it's designed to when it comes to amps. This means that as long as you have the amperage to drive the ignition's minimum requirements, the spark will not change. Anything over that is unused and left in the battery. Otherwise you'd blow out things like your coil packs if you didn't have the blower motor on full blast.

 

yuo should just stick with the aem and take the precautions in order to prevent hydrolock. I haven'nt heard of anyone who hydrolocked after installing the "umbrella" and/or covering the drain hole above the headlight. That should be more than enough precaution and the water won't be an issue after that. Others have not even done these precautions and they still have had no problem, but me I like to play it safe and did both the umbrella over the filter and covered the drain hole. Has anyone heard of water issues/problems after these two steps were done?

 

if you sealed off the intake duct only allowing airflow in by the piping it would still be drawing in cooler air... i dont think the fan is going to do much in any event unless you had it before the tubing to cool the air as its coming in. I think you would be dealing with alot of airwave science with the fan in order for it to be effective enough to where its worth using.

 

even though the electric motor is not physically connected so to say, reversing blades or not letting it turn as it wants to, will cause havoc on the electrical system.

a motor is the same as a generator, turning the blades will cause back emf.

 

Oooh, good point, any fan like that would cause some nasty power feedback no matter what was going on with the fan itself. Fans are notorious for screwing up power circuits.

 

What about the electric fans already on the radiator? Why don't they cause problems?

 

I imagine they have quite a bit of caps, resistors, and such to help smooth out the power they pull.