what about an expansion pipe???
OK, it would take some figuring but this would be trick!
In the early dirtbike days, if you wanted a performance exhaust you about had to make your own. It was done in the form of an expansion pipe. Basically, two funnel shapes put together on the large ends. It increases flow velocity and if it is tuned (adjusting the length and taper diameters), it can produce a relative pressure/velocity increase at the exit, which would be the throttle body inlet if set up on an intake flow. I'm pretty sure the same physics would work on intake flow as well as exhaust.
If you consider a volume of air flowing through a tube at a certain velocity and relative pressure, if the tube diameter increases, the pressure drops and the flow volume increases. (I'm struggling with terminology here.. but...) Restated- The pressure drops. The flow rate decreases but the flow volume (cu.in. of air) increases. This is the key... This increased volume of air has mass and inertia, aka "increased flow". As it moves to the reducing diameter funnel, the mass of air is compressed. The flow rate (velocity) goes back up. Add to this the increase of pressure and the inertia of the air mass coming through the expansion chamber and a relative positive pressure is exerted at the chamber exit. I say relative pressure because in this application the flow is produce by a vacuum rather than a pressure. The key is to end up with more relative pressure coming in to the throttle body than is seen at the expansion chamber inlet.
Got any sheet metal buddies? Do they like beer?
Whaddya think?
