The engine simulator offers three calibration inputs. They are used to adjust output values from the simulator.
Once you have entered some data for an engine for which you have a dyno chart or otherwise know the actual power output, you can use any combination of the calibration inputs to adjust the accuracy of the simulator. Then, when you change values in the simulator inputs, the outputs are even more accurate.
You can calibrate by engine speed (RPM), which moves the output from side to side. You can also calibrate by percentage and HP, which both adjust the output vertically.