Diesels are very different. Raising boost, increasing airflow, etc, dont necessarily produce power as they do in our application. Its all about burning fuel. In fact there is no air throttling done at all. The gas pedal is connected to the fuel pump
There is also no real boost control. The wastegate is more of a pop off valve, simply limiting maximum boost. Many diesels have no wastegate what so ever, and you have to be careful not to over spin the turbo. The more fuel you burn, the more boost you get, and thats how you get more air. Adding too much fuel will increase EGTs, the safe limit for the cummins turbo diesel is considered 12-1300 degrees F. If EGTs go over that you need to reduce fueling, or increase airflow. So the larger exhaust will allow me to add more fuel before EGTs get too high. Still need to find a way to add that fuel though. Injectors, chip/box, etc.