That is not supercharging. A computer fan is not designed for compressing air, and it's nowhere near powerful enough to do so. There may be a small increase in performance, but that is just because you overcome the restrictions (increasing airflow) in the inlet manifold

The so called 'electric superchargers' which you can buy on ebay have been mythbusted many times [0]

[0] https://www.youtube.com/watch?v=cbGWgvJN1_8

I think I rememeber seeing someone hooking up a highly modified leaf blower to the intake of a car and getting like a dozen more HP. This was a part of a bunch of experiments with the electrics turbos, and the the leaf blower was the only thing that worked?

Yup, it takes not only high pressure, but a high volume of air. Add to that the need to squeeze more air through existing small ducting, and you need quite a bit to make a difference. Turbos work by their intake being powered in close relation to their exhaust volume. The rest is just effeciency curves and fueling issues.

Roadkill did it with both multiple leaf blowers (https://www.youtube.com/watch?v=U81_0waqEWA) and a full small block Chevy engine on a trailer supercharging another one in the car (https://www.youtube.com/watch?v=VPMBR-imqUk).

That sounds more like a variant of cold-air induction.

Does it actually work? I might try it.

Very much so. Get the a good fan and make as tight a seal as possible between it and the air intake.

Thanks! I have to try it.