air flow
not sure how much good that would do on my GM alternator but could maybe mod it to fit somehow, or "nearly" fit, which is better than just pointing the open end of the duct in the general vicinity of the alt, now here's a thought:
I believe air flow through the engine bay is up from below, out through the top, so pointing my air duct down at the alt is bad, routing to below would be best as the cool air would dump into it as it draws the air up and through.
The other day I forgot to latch my engine lid (as I've done before), at anything above 40ish it starts to rise, at highway speed, it's straight up, great cooling, silly looking, no rear view, bit embarrassing, like leaving your fly open maybe. Does illustrate how powerful the air movement is though, enough to raise the pretty hefty lid like it's paper.