You were correct. I spent a few days playing with that part of the intake and
I tried it. With the snorkel off in the city I saw the temps get up to 126
. But with the snorkel on I saw 106. I'm pretty sure thats right because the temperature was 100 degrees in the shade. I didn't see as much on he highway (maybe 3-6 extra degrees at 50 mph)
If your going to try logging the temps, I would log after the engine has been running for a while to get everything warm. Then log one drive with it taken out and another with it in. I have some driving graphs where I recorded IAT by accident and they dont say much. They basically say that the temp went up about 1-3 degrees per minute until I got enough speed to blow cooler air in. When I was looking into temps for the intake I did a few at idle and they said the air is about 20 degrees warmer without the snorkel.