A method for programming an internal combustion engine control unit includes operating a test internal combustion engine at a first speed and a first torque while simulating a condition of the test internal combustion engine by restricting a flow of air to the test internal combustion engine to simulate altitude variations of the test internal combustion engine or elevating a temperature of the flow of air to simulate ambient temperature variations of the test internal combustion engine. The method also includes measuring engine performance information while operating the test internal combustion engine at the first speed and first torque and while simulating the condition of the test internal combustion engine, and programming the internal combustion engine control unit by storing the measured engine performance information in a memory associated with the internal combustion engine control unit.