The thing is that on a beetle motor you can not use such a fan like in your link. It has got to be the existing fan. You see, on watercooled engines, the water flows through the radiator which increases the surface area that can be cooled by a fan that blows along the electric motor's turning axis. The beetle fan blows air perpendicular to the alternator/generator's axis.
So the only alternative that you have is to swap to a completely different alternator(placed elsewhere in the engine compartment), and then fabricate something up that attaches to the original fan, in place of the alt/generator. And obviously this electirc motor needs to put out the same turning speed than the alt/gen. I am not in the position to say if such a electric motor exists
I am sure that in the glory days, if this was possible/feasable to do, they would've thought about it back then and we all would be using it now....
By all means, it can still be looked into and tried, but I am sure that most out there would rather spend that kind of money on something that is tried and tested to give that extra percentage power. Like dual carbs, bigger crank etc etc.
Your theory does have some (obvious) grounds that you can release some HP by disconnecting the alt/gen... This is exactly what drag racers do(professional or at shows/meetings). But most of them claim about 5hp or so difference. In my personal view, that kind of HP is not worth spending all that money on......
Just my $0.02, after all, that is what forums are for, no?
