On my supercharged 2012, I run the MCT switch enabled and read IAT at the MAF and the manifold.
Another common approach is to reroute the new sensor into the MAF harness, replacing the integral MAF temp sensor signal, with the new manifold temp sensor signal. But I have wondered, since the sensors themselves are quite different, how different are the transfer functions.
Not all strategies have both transfer functions visible yet in HPT, but I pulled a fair amount of data to compare:
IAT transfer functions.jpg
What we see is two distinct "types" of transfer function: S-curve, and linear.
My 2012 FPDX has the same linear MCT function as the 2015 GT shown in this graph, and mine does seem to indicate accurate temps. But I have never tested it for accuracy. I guess in the "normal" operational range, the difference wouldn't be blatant.
All the other calibrations have the S-curve data for the secondary temp sensor.
So the question I am left with, is which one is correct? Is the linear data just "filler" data for an unused table, or does it really match some available sensor?