stubones99
Guru
Derating an engine is done at the manufacturer, unless you replace the injection pump with a different rated engine model, which would be an expensive move. Also, if you know the internal mechanics of an injection pump (Fuel Injection Engineer) you could adjust the power / torque curves. My older brother was a diesel fuel injection engineer and he could do it. Average joe turning a screw is setting the throttle limits, changing where it stops the throttle / rpms.