[71RoadRunner]

There is a little logic in their advertising when they talk about increasing fuel mileage, however this will only apply to carburated or throttle body fuel injected vehicles. Multipoint or direct fuel injection doesn't apply as much since they inject the fuel directly into the combustion chamber. The way it does actually work is by causing the turbulence which helps to atomize the fuel into the air making it burn better and more completely, which makes more efficient use of the fuel. This can also improve low end power and response making it seems as though they have more power, which they do, but only at the low end, at the top end or at peak power they do nothing and may actually hurt the power and performance.

This is where porting in polishing come into play, they create more volume and smoother flow to maximize the amount of air getting into the cylinders which will increase peak power and top end performance.