Shown below are the results of the first drive with the air temperature sensor located on the back side of the air filter.

The most remarkable result from this drive is that the temperature inside the airbox, after the air filter, exceeds that further down the intake, prior to entering the turbocharger compressor housing – labeled TOdegF.  From just after 1000 seconds until around the end of the drive the intake air is being cooled by the intake piping, relative to the temperature it reaches inside of the airbox.  That never occurred on the previous drive and raises the possibility that the air filter is contributing a fair amount to the warming of the intake air.

There are a couple of differences from the prior drive, the outside air temperature was about 15 degF greater, and there was a bit more stopping during the first portion of this drive.  The prior drive is shown below:

I will be making at least one more drive with this configuration to check for consistency in the results.

After reviewing the temperature measurements from the last drive home I decided that I wanted to move the airbox temperature sensor probe from the pre-filter side of the airbox to the post-filter side.

I set about making this move when I hit a snag, while attaching a 7mm socket to the end of a wrench the socket fell, down between the radiator carrier and the engine.  It bounced off one part and then the dreaded silence, indicating that it had not fallen through to the garage floor.

Peering down between the spaces I could not spot the socket, and as the photo above indicates, I had to try a bit more to see if I could find the stray tool.  Unfortunately even with the front end in the service position I could not find the socket nor bounce it free from wherever it landed.  I wasn’t going to drain the coolant to pull the whole front of the car off so I resigned myself to settling to use a 9/32″ socket instead until it either the 7mm falls out in the garage, or I purchase a replacement 7mm socket.

I continued on with what I had come out to the garage to do 90 minutes earlier, repositioning the air temperature sensor to the post-air filter side of the airbox.

The airbox was reassembled and positioned back where it regularly sits.  This sensor will work in conjunction with the sensor shown below.