Turbo Concepts Stg1 Temperature Rise

A pair of readings that I often take when logging the car are the air temperature going into the turbocharger compressor, and that when it comes out.

Auber pressure sensor installed in intake pipe

Shown above with the arrow is the location where the temperature reading is taken of the air entering the turbocharger compressor.  The sensor in the picture is not a temperature probe.

Auber Instruments Air Intake Temperature Sensor
Auber Air Temperature Sensor installed in charge pipe joining turbo and intercooler

Above is the location of the temperature reading for the air exiting the turbocharger compressor.  This is the hardpipe that joins the compressor outlet to the intercooler inlet endtank.  I believe this temperature reading is somewhat lower than what exits the compressor due to cooling that takes place in the hard pipe prior to reaching the probe tip.  Since this same location is used for each setup I have tested, even though the measurement is probably not an accurate reading of the compressor outlet temperature, the relative performance between different turbochargers should be correct.

I have found that even without any boost (compressing the air) taking place the mere passage of the air through the housing and compressor wheel causes the air temperature to rise around 25 degrees Fahrenheit.

Shown below is a boost profile that I am operating the Turbo Concepts Stage 1 turbochargers at:

Turbo Concepts Stage 1 Boost and IAT @ 48F
Turbo Concepts Stage 1 Boost and IAT @ 48F

These readings were taken when the ambient temperature was 48 degF.  Also shown is the intake air temperature as recorded with the car’s charge air temperature sensor.

The rise in air temperature through the Turbo Concepts turbocharger when operated at the boost level shown above is displayed in the chart below:

Turbo Concepts charge air temperature rise
Turbo Concepts charge air temperature rise

This is showing how much difference there was in the air temperature leaving the turbocharger compared to the temperature upon entry.  Note that even though the boost pressure drops over the course of the pull that the air temperature is rising.  The compressor housing acts like a heat sink, absorbing energy from the air when it is compressed.  Over the time span of the pull the capacity of the housing to absorb energy declines, and the energy remains in the air, leading to the temperature rise.

It’s important to keep in mind that this chart is showing relative temperatures, the temperature of the air entering the turbocharger is approximately 60 degF in the case with the lowest starting temperature.  By the time the air is compressed, in each case it leaves the turbochargers above 200 degF.  As was pointed out, the location of the outlet probe results in a lower reading than is the true outlet temperature.  It’s likely the true outlet temperature could be 25-50 degrees hotter than what is being recorded.

Another interesting aspect of this data is the IAT compared to the compressor outlet temperature.  After the charge air passes through the cross flow heat exchanger (Silly Rabbit Motorsport Intercooler), and is hit with a squirt from the 4mm Aquamist nozzles I use with a water-methanol injection setup, the temperature is dropped from over 200 degrees to between 78-92, not too far above ambient temperate.

Next up I’ll be comparing these results with some of the other turbochargers that I have measured.