Just think of bikecycle tire hand pump, if you still can't imagine what Nathan is referning to of how the fuel and air mixture
get's VACUME.


The venteri is sort of like an airfoil.....( imagine a garden hose nozzle.)
That's why there's lift. The air has to travel a greater distance on the top side of the airfoil, therefore the speed of the air flow increase.
The air hits the leading leading edge and meets at the tailing edge at the same amount of time.


basically a tune pipe is line a venteri..it creates vacume on the exhaust side.