Background:
A previous post discussed the development of a Mk8 PCV port adapter that would allow a temperature probe to be inserted into the Blaze ATOM inlet hose to measure the intake air temperature before it reaches the turbocharger compressor.
This presents an additional opportunity to measure the air temperature at the PCV port with the Mk8 PCV in a couple of different configurations.
Test configurations:
With the full Mk8 PCV conversion, a line supplies bypassed charge air into the intake. This bypassed air is at a higher temperature than the intake air due to the turbocharger compressor compressing it.
The line does not supply a large quantity of air, but air at 200-300 degrees Fahrenheit being supplied to the intake side of the compressor wheel is undesirable.
This configuration is described as the Blaze (Venturi).
Disconnecting this supply line is a second configuration that more closely replicates an Mk7 PCV setup. The vacuum inside the intake can still pull some air from the crankcase. This is described as the Blaze configuration.
The final configuration involves disconnecting the PCV adapter, described as the Blaze (No PCV).
The intake air temperature measurement before the turbocharger is recorded during a series of full-throttle third-gear pulls. The results for each configuration are averaged.
Test results:
The outside air temperature (OAT) is similar for all three test cases.
Disconnecting the PCV lines produced the lowest intake air temperature, as shown by the orange line in the chart below.
A higher pre-turbocharger air temperature is recorded when the PCV line is connected, and the venturi line is disconnected. The blue line represents this.
With the attached venturi line, the highest air temperature and a significant air temperature variation are recorded. The red line in the chart above shows these.
The next chart shows the data collection for the venturi line attached case. The pre-turbocharger air temperature increases significantly with the subsequent pulls, causing the variation seen with the average line.
The turbocharger outlet air temperature also increases with the subsequent pulls.
Conclusions:
The Mk8 PCV system was tested in three different configurations to evaluate the effect on the pre-turbocharger air temperature.
The lowest pre-turbo air temperatures were measured with the PCV system disconnected. Attaching the PCV without the venturi line increased the pre-turbocharger air temperature. Connecting the venturi line produced a greater increase than attaching the PCV system.