Just spotted this on ebay:
turbo spiral

They claim increase in fuel efficiency and power.
Quite honestly I doubt this because the unit is nothing more than a rotating fan, driven by the air that is sucked into the engine, so from my point of view, what this does, is actually REDUCE airflow, which I suspect will have the opposite effect of what they state in their advertisement.
However, I could be wrong and if so, I would love to hear how the principle works...

>

your exactly right.
its junk.