On the topic of the IAT relocation:
I messed around with a couple intake setups. Ended up with my current one, threw relocating the IAT sensor and a computer reader,I mapped out air/fuel mixtures and intake air temperature. There's huge differences between the free air temperatures. Stock intake my temperatures were 99-101 degrees at running temperature. I relocated the IAT sensor just short of the stock intake box and it was still around 98-100 alibi: i did not have that little horn on the box. After making a super low budget ie. 50 dollar, intake setup and mounting the IAT sensor prior to the cleaner the temps dropped to 94-95. Then I made a heat shield and attempted to close it off totally from the engine compartment and made sheet metal modifications so air flows around the hood into the chamber and around the passenger side headlight into the chamber, the temps dropped significantly to more or less outside air temperature, I've seen low 50's in the winter since, but the day I did it for comparison sake was 77 degrees. When the ECM maps out the fuel mixture it takes the IAT and manifold absolute pressure together to configure the air-fuel mixture. So yes the ECM does know. This is no theory, I've worked on the Turbine engines on the aircraft I now fly, their are giant curves in performance for intake air temperature. Obviously not as substantial on our 4.0L. And it doesn't just ramp your mixture up to rich either, it maps it out, at idle and up threw 1/4 throttle there's little difference, where it jumps is prior to and at WOT. I try not to end up there, but there is a change in fuel mapping. I try to be conservative in the modifications I do and driving, I don't want a gas guzzling hog, I could care less about being fast, my goal is overall engine efficiency with a delectable exhaust tone.
Notice the postition of the IAT sensor right prior to the heat shield:
This video was before the porting of 99+manifold and head, and before the APN headers.
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Background on my engine setup: 98 4.0L with homemade intake, Flex-a-lite electric fan, 62mm throttle body, 99+ ported intake manifold, ported head, indexed and side gapped auto lite spark plugs, APN headers 2.25" at the collar to 2.5" pipe around and out to a Flowmaster super 40 series and out the back. Choking it down to 2.25, then back up to 2.5" helps the low end torque.