my X300 is an XJR , supercharged, so the air compression in the supercharger generates a lot of heat.
Typically, data from OBDII reader gives air intake temps about 25’-30’C higher than ambient after a hard sustained run, dropping to about 16-17’C above ambient after a few miles of gentle throttle. I understand the air intake temp sensor is in the inlet manifold, close to the head, so presumably some heat radiates from the head to the inlet runner, as evidenced by the apparent rise in intake temp when the car has been parked for 10-15 minutes after a run, then is started up again.

today I bought a cheap temperature sensor with a 2.5 meter wire to the probe, and drove with the probe taped in various positions under the bonnet.
it is winter here, and the outside temperature dropped from 11’ To 7’C whilst I was doing this.
i initially taped the sensor to the snorkel mouth of my standard air box. In light traffic it read about 4-5’C above ambient, but within a kilometre of open road at 80-100 km/h, was reading the same as ambient, ie: 11’C.
To me, this negates the need for a cold air induction (at least, for open road use in winter!) and validates my decision to revert from K&N pod back to std air box and paper filter (I spend minimum time in heavy traffic).
I can still max out my MAF at about 4200 rpm at full throttle with a 10% larger Powerhouse drive pulley, so I don’t need more airflow.

i then tried the probe taped to the aluminium ducting where it says ‘XJR6’ in red paint. That read a steady 20’C with ambient temp of 8-10’C, so air flow getting a bit warmer after it has run over the top of the inter cooler housing. At this point, air intake temp on the OBDII was about 28-30’C, so the intercooler with its new Bosch water pump is doing a good job. Admittedly, it is winter, and this was after several miles of open road motoring, the last mile or so at about 90-100mph.

i then taped it to a small brake pipe at the rear of the engine bay, exhaust side, and it would rise as high as 47-50’C when stopped in traffic, quickly dropping to 33’C when moving.

I’ll repeat all this in the heat of our summer (30’C plus), then try the TWR XJS trick of popping the bonnet open to increase airflow out of engine bay to see if this makes a difference in an XJR...