Quote:
Originally Posted by Megahurtz
Pretty sure IAT 2 is pre rotor and intercooler. I see IAT2 drop on stock cars.
IAT3 is allegedly the true post rotor temp. MAT's are calculated based on multiple sensors.
That's how I've always understood and tuned with.
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Hey Megahertz...
It's my understanding that IAT.2's come from the TMAP sensor at the back of the drivers side blower (post intercooler bricks) Which is why those numbers will / should decrease after a pull thanks to higher air velocity, and reduced heat soak from the intake runners / blower. Air is moving too fast to heat up. (this assumes your HX system is working properly) The only problem that I am aware of is that the OEM sensor is very slow acting, and does not accurately capture spikes in temp changes.
Which is why I am adding a new RIFE IAT sensor on the passenger side, as well as an IAT temp sensor on the hot side of the blower. I am not certain, but I believe I'll be the first. Doing this to better support future testing and system design. Stay tuned for more on this one!
MAT's are calculated as you noted, from RPM, Speed, ECT, EOT, Ambient Temps, Boost Pressure, etc...
I guess the logic is that it would be too risky to base your timing curve on the actual IAT.2 sensor data, and should there be an issue with the sensor the car could suffer. It seems much safer to base the timing table on a calculated number that ignores the spikes in IAT.2 if they did exist. The problem for us, is that number is heavily biased for safety, not power efficiency.
I suppose thats why many tuners will raise the IAT.3 threshold for timing being pulled?
That said, do you ever adjust that table? If so, can you share your methodology?