[JRMichler]

I did not clearly write what I was trying to say. If most of your driving is at a particular RPM, then efficiency at that RPM is of interest. Efficiency at 5000 RPM is not of interest to an ecomodder.

For example, testing heated intake air need only be done normal highway RPM and below. Testing at a particular RPM is done over the complete range of manifold absolute pressures. At each MAP, measure the torque and fuel flow. Do this for a range of RPMs, starting at idle and ending at normal highway RPM. Repeat the entire series of tests for different intake air temperatures.

Plot the results as an engine performance graph, with temperature on the horizontal axis and torque on the vertical axis. One graph for each RPM. Each individual test at a particular RPM will add a specific fuel consumption value to the graph for that RPM. The finished graph will show the relationship between peak torque and intake temperature. It will also show the best intake air temperature for any torque at that RPM.

The same data can also be plotted with RPM on the horizontal axis, torque on the vertical axis, and specific fuel consumption as the data. One plot for each intake air temperature. This a conventional engine performance map.