I got a question.There's an advertisement where this guy is advertising this so called Tornado to increase horsepower and save gas.How is that possible?If I'm right when you increase HP your gas mileage drops.Am I right?So how do you increase HP and save gas?I want to know.I'm sorry I asked 3 question not one.LOL

I've seen that tornado thing, looks like garbage to me.
I believe it is just a couple little vortex shaped fins that insert into your intake.
It can't do much of anything. My opinion

I believe what you are referring to may be something like the Electronic Supercharger advertised on eBay.com.

The whole idea of this device is to force air into the engine rather than rely on the engine to **** the air in as normal. As this device forces the air in (at a low pressure - no-where near that of an actual supercharger) it means that more air enters the cylinder on each induction stroke, therefore sucking more fuel in which gives you a bigger "bang" in the cylinder - hence more power.

What this device says it also does is give you a more efficient "burn" - this is usually achieved by creating a swirl or "vortex" in the intake air antering the engine - this swirl helps to mix the fuel up more evenly, which gives a more efficient cumbustion in the chamber.

The more efficient mix of fuel and air means that on combustion, the fuel-air mix will burn more quickly and therefore expand more quickly. Now if your car is feul injected and has an exhaust sensor - this will detect a rich burn at first (well - second or two) and inform the ECU to reduce the fuel flow to the cylinders - thus reducing the amount of fuel you use per cycle.

So when you look at it all together, you use less fuel, but get a bigger "bang" and hence more power, but less fuel usage.

A product called the Ecotek Valve does a similar job - but it does not force air into the engine - it purely creates a vortex in the air entering the cylinders.

I hope this answers your question :D