318 MAX fuel economy builds?

To actually use the above circuits, you have to start with them at minimum value -- as close to "Off" as possible. Most ECUs will look at the temperature values of every temp sensor on the vehicle on Key-On; this would include the IAT, CTS, cabin temp sensor, even the cat temp sensor (heater circuit of the down-stream O2 sensor). If there is a consistent discrepancy in one of the sensors, the adaptive strategies will compensate around the calibration issue. The resistance change has to be slowly ramped in to chosen setting. For the CTS, ramp in the offset as the engine can handle it, then when the total circuit value reads normal operating temperature, it has to be ramped back down. Otherwise, the ECU sees an over-heating condition. On some vehicles, this will trigger the cooling fan -- which wastes fuel over-driving the alternator. Many vehicles will dump excess fuel to try to cool the engine from the inside.

This is why I would use a small 8-bit PIC processor and a digital pot. The whole "turning a knob" becomes software.