Model 40 for HX40 turbo used on Cummins 8.3 and on 5.9 upgrades
It is no secret that the factory boost control system on the HX40 is a poor design. The factory control is a spring-loaded canister. The PCM sends a small amount of boost to the canister to overide spring pressure and allow the wastegate to open. The downside is the wastegate opens and closes often prior to "set point" simply because of it's design. Aftermarket "actuators" simply are higher tensioned springs. You could accomplish this simple task by shortening the wastegate rod. It delays the "set point", but doesn't overcome the issue of the wastegate's lack of staying shut until desired. The Turbo-Master waste gate controller is created as a direct, bolt on replacement for the factory spring loaded canister. In combination with the factory waste gate valve, the Turbo-Master forms a fully adjustable, turbine inlet-pressure (drive pressure) relief system. With the Turbo-Master, turbine inlet pressure is retained up to the preset point of bypass. This results in turbocharger performance that is increased across the design operational range. Even on an otherwise stock Cummins engine performance is increased by virtue of the resultant steady boost pressure.
