Duct 7 – APR PEX


The air temperature results using the IE V2 intake prompted me to go back through my records to see if any of the other intakes I’ve used were logged similarly.

I found the APR PEX intake had been installed when I had the pre-turbo air temperature sensor installed, so this gave me the opportunity to see how that intake setup compares to the previous configurations that have been tested.

APR PEX Intake - Installed
APR PEX Intake – Installed

Test Process:

The drive made when I was recording data with the APR PEX is very similar to what I have done with the various prior Duct tests.

The car is driven to a location suitable for making full-throttle acceleration pulls. This provides some time for the engine components to warm up. Then a series of pulls are made with a short break in between pulls. These pulls are made in third gear beginning at approximately 2,000 RPM and concluding around 6,300 RPM. The air temperature entering the turbocharger is measured during these pulls.

At the time that the APR PEX was installed, the GTI was operating with the Shuenk IS38+ turbocharger.

Test Results:

An overview of the recording session with the APR PEX intake is shown on the chart.

APR PEX Session Overview

Configurations that are being compared in the remaining charts are:

Duct Configuration LabelDuct Configuration Description
D1CTS Intake / Stock Air Duct
D2CTS Intake / Stock Duct w/ Open Driver’s Side
D3CTS Intake / Stock Duct w/ Open Drv. Side and Covered Rear Pax Side
D4CTS Intake w/ Foam Around Heat Shield / D3 Configured Air Duct
D5CTS Intake Without Heat Shield / D3 Configured Air Duct
IE V2 (D6)IE v2 Intake / IE v2 Air Duct
APR PEX (D7)APR PEX / D3 Configured Air Duct

The first chart shows the Turbo inlet air temperature versus the outside air temperature at the start of the pull.

The square symbol is the mean temperature difference value. All temperature measurements are in degrees Fahrenheit.

The next chart shows the pre-turbo air temperature rise, or fall (if below zero), during the pulls:

The final chart shows how high the pre-turbo air temperature is above the outside air temperature at the end of the pull.


Pre-turbocharger intake air temperatures were measured with the GTI equipped with an APR PEX open intake and the results compared with several other configurations that have been tested.

The APR PEX pre-turbo air temperatures were equivalent to or better than all of the other configurations that have been tested thus far.


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