During the course of taking measurements of intake air temperature I decided to log the turbo compressor intake air temperature under some harsh conditions.
Temperature of the day was around 90 degrees and a thirty minute drive had been completed. The car was parked with the hood down for about twenty minutes. At this point a second drive was started and the temperature of the air entering the turbocharger was recorded.
The intake in use was one of the better ones that I have tested for isolating the intake air from the engine compartment air. As the chart shows by the orange line which is the air temperature entering the intake, the air temperature of the air entering the airbox quickly drops to close to ambient.
Of main interest to me is the blue line, the temperature of the air as it enters the turbocharger. Starting just under 165 degF it drops rapidly then steadies around 30 degF above ambient. During a stop the temperature spikes again, and then with some driving it eventually drops to around 25 degF above ambient.
The most interesting result from this experiment is that under extreme starting conditions the temperature entering the turbocharger can get close to what is normally experienced during a cold start drive of this length of time.