by Charles Owens on 03/29/2013
Technical Product Focus: Boyesen Power X-Wing
The Relationship Between Air Velocity and Engine Performance
“Most people believe that an internal combustion engine is an explosive device-where fuel is lit off much like fireworks on the Fourth of July. Not true! Motorcycle engines are air pumps. Air is drawn in, compressed by force, expanded by combustion and expelled out the exhaust. Contrary to popular opinion, there is no explosion. The engine processes air, mixes it with fuel and burns the air/fuel mixture in a very orderly process. Once you understand how an internal combustion engine works, you can understand that the transition of air, from the air box to the exhaust stinger, is all-important. Nothing matters as much in the production of horsepower as the maximization, control and flow of air.
The Boyesen Power X-Wing works like an airplane wing. It takes a given volume of tumbled air and straightens it out. The goal is to achieve laminar flow. Laminar flow is the smooth, uninterrupted flow of air over the contour of a wing. The Power X-Wing reduces drag at the air’s boundary layer, reduces surface friction drag, equalizes the pressure gradient and increases air velocity.” – Motocross Action Magazine, Web Article – 2011
How the Power X-Wing Increases Engine Performance
In order to understand how the Power X-Wing increases engine performance, a careful study on the importance of air velocity and how it relates to your engine’s ability to regulate horsepower response is in order.
Simply put, the air velocity generated within your intact tract is one of the most important factors in increasing the response and overall output performance equation.
The Power X-Wing increases air speed (velocity) at all throttle settings. It does this by forcing a laminar streamlining of air into the carburetor or throttle body. Most stock intake systems deliver turbulent, un-streamlined air as a result of the disruptive and angled air box and intake tract – this turbulence limits horsepower and response because it limits how well fuel can be mixed with the air during its time in the carburetor or throttle body. To improve the air and fuel delivery of stock intake systems, Boyesen designs the curved protrusions of the Power X-Wing to guide and direct how the air condenses and where it is directed as it comes into the bell of the carburetor or throttle body. As it is guided into the throat and bore, the Power X-Wing straightens the air through its four channels and walls, effectively minimizing turbulence. As the incoming air becomes less turbulent, the molecules are calmed down and take up less volume. The molecules are forced closer together and produce a denser air charge. This charge also increases in velocity, because stable and less turbulent air creates less friction when it moves at higher speeds. The air, which is now more laminar (smooth) in flow, is better able to cross the butterfly and shaft barrier, which especially has the effect of improving velocity going into the engine. This is particularly true at part throttle, because the Power X-Wing’s four-channel design separates the air and packages it within the individual air passages of the X-Wing-creating air stacks. At smaller throttle openings, these optimally packaged air stacks create a greater proportional increase in air velocity when compared to stock setups.
Riding is Believing
With the incoming air velocity being optimized, the engine’s cylinders can be filled more freely. With higher air velocity and denser laminar flow, the air increases its ability to shear the fuel droplets and therefore improve atomization. The resulting combustion process becomes more efficient, complete and effective, producing better torque and horsepower while at the same time enhancing fuel economy.
Another “seat of the pants” performance benefit that results from superior cylinder filling efficiency is the fact that less drag is accumulated at the crank as the intake stroke happens. This is energy gained by the crankshaft, which also gives a smoother crank rotation. The result of the phenomenon is a much smoother power delivery, better throttle response and stronger acceleration.