I was testing the actual value of the air in the intake and comparing it to the OBDII IAT value. What I found is that the IAT is fairly accurate as to the running temp of the air in the intake, but is is very slow to react to sudden temperature changes.
If I floored it the IAT would take quite a bit of time to change. But the test probe I had showed an immediate drop in temperature.
This was all done with mid 50F ambient temps and the IAT showing ~70F or 15F above ambient. The two temp probes read within 2F of each other when at the same ambient temps.
Anyway, it was surprising to see a big drop to near ambient with in a couple seconds yet the IAT did not budge. Only after the turbo had heated up the air a bit and temps coming out of the IC were around 70F did the IAT start to fall, then go back up, There seems to be a great deal of latency in the factory reading.
So you get a big slug of cold air but the ECU does not see it to adjust the fuel or spark. I would think theres some neck snapping being left on the table here.
I searched and came across a thread about a Fast Acting IAT.
Fast acting IAT sensor [Archive] - Club Protege
They had success using the Triumph 955 IAT sensor.
So I need to see if the resistance readings are the same as ours. They probably are.