AirDog® II-4G is designed to operate at flows and pressures beyond the maximum requirements of the engine. It receives fuel under vacuum from the fuel tank containing entrained air/vapor, particulate contaminates and unknown quantities of water. The fuel passes through the water separator which removes the large particulate contaminates that could damage or jam the gear rotor fuel pump. The fuel, with only entrained air/vapor and tiny particulate contaminates remaining enters the fuel pump. The fuel, now under positive pressure flow, enters the fuel filter. As the fuel passes through the filter media and the remaining particulate contaminates are caught and contained, the entrained air/vapor is also separated. Through the positive fuel air separation features of the patented AirDog® II-4G the separated air/vapor is discharged from the filter and back to the fuel tank through the Primary Air/Vapor Discharge Port. The fuel passing through the filter media is now free of contaminates and power robbing air/vapor. At pressures and flows able to meet the needs of the engine, it exits the fuel filter through two passageways. First, the fuel for the engine passes into the fuel pickup tube and on to the engine. Then, the excess fuel not needed by the engine recycles internally through the pressure regulator back to the water separator. Benefits of the AirDog® II-4G: Increased Fuel Economy Increased Power Output Increased Torque Output Longer Injector Life Improved Throttle Response Reduced Exhaust Emissions Optimized ENGINE & PERFORMANCE AirDog® II-4G also overcomes loss of power for diesel engines operating at higher altitudes.