a turbocharger pushes a huge amount of air at fairly high pressure, I doubt that a small fan like a cpu fan could even keep up with the air flow being taken in by a standard small engine, nevermind exceeding it, so it would mostlikely just add more resistance.

A device using PC fans has already been created. Read about it at AutoSpeed.com.au, which explains why something like this will never work.

the idea is ok but it would never work. the reason is that the vacum careated by the intake is so much more than a small fan like the one u discribe can generate that it wouldn't make a defferance in fact it may reduce the air intake, as it wold slow down the air flow at running speed. I know this bc I'm a macanic.