Originally Posted by Bajaman

Obviously the PC enables the fuel to be burned quicker, else how could the engine obtain rpms near 5K vs 3K common in DI engines. This is further shown in the difference in start of injection timing. IDI engines commonly inject at 20+ degrees BTDC whereas the Cummins 6bt as an example is somewhere around 15*. Again the PC allows the fuel to be injected earlier and the pressure rise is delayed apparently via the PC. Just some thoughts to add to the mix