The HP numbers are flawed.
Although the comparison between each of the*fans would be similar to each other. In real-life, all the fans*are*all fed moving air (um.. vehicle is*moving), and therefore using less power overall.
This test needs to be redone with wind speed in the dyno cell of 60mph to have relevance to actual conditions -if at all possible.
Anyway.. OE clutch fans rule. I can't stand the horrid white noise of electric fans that you often hear before the V8 rumble.
PooManchoo2 People keep making this comment and it's true, but there's another thing to consider: Engine compartments, especially on older vehicles, are not free flowing. There can often be pressure under the hood at road speeds. It's not as simple as "the fan is being fed air at 60 mph, so it's not working as hard."
That may be true too, but it's also a well known fact (in almost all vehicle*cases)*that you don't even need a*fan when*at speed. This*is proof of lots of free flowing air, and proof that any fan in use*will be consuming far less power than when having to pull stationary air like when*in the dyno cell.
I'll bet that*the OE clutch fan uses less than half of what the test said it does*in real life.
In fact, I think I remember HRM (maybe while you were there) did a chassis dyno test and reported only 5 rwhp*using*an OE clutch fan.
I'll also assume that the car on the chassis dyno was fed moving air as standard.