Continuing the series of bench tests where intercooler options for the Mk7 GTI are tested for cooling efficiency. The next product to be tested is the Audi Performance and Racing stock location intercooler.
Briefly recapping, the intercooler has heated air flowed through it with the outlet air temperature measured throughout the test. After two minutes of heating a fan is turned on to force air through the core fins while the heated air continues to be flowed through the core.
The outlet air temperature over ambient readings from the APR intercooler are shown on the next chart along with the stock Mk7 GTI intercooler.
Previously the APR intercooler was flow tested on the flow bench but the results were obtained with a slightly different setup. The APR IC was retested using the current configuration that uses intercooler hoses and an adapter to the flow bench that is more representative of the throttle body attachment on the GTI.
With the new setup the APR intercooler flows 216 CFM @ 28″ of H2O.
Adding the bench cooling test to the data obtained with other intercoolers produces this chart:
Applying both the cooling performance and flow performance to generate a data point on the composite performance chart:
The bench cooling results for the APR intercooler are very similar to the other aftermarket intercoolers for the first 75 seconds of the test. After 75 seconds through to the end of the test the APR intercooler shows greater cooling versus the other intercoolers. Near the end of the cooling phase of the test the Forge intercooler approaches the cooling performance of the APR intercooler.
For the cooling criteria chosen, temperature rise at 2 minutes into the test, the APR intercooler has the best performance of the intercoolers tested. Airflow through the APR intercooler is second best among the products that have undergone both bench tests.
The APR intercooler overall performance is similar to the Unitronic intercooler. For this reason the APR IC will be installed on my GTI for further testing.
As bench data is recorded and can be compared with vehicle data logs for different intercoolers how well the two correlate will be better understood. It is possible the performance criteria from the bench test will be adjusted to better correlate with vehicle data logs.
The criteria for comparison on the composite chart is airflow at 28″ of H2O and degrees of temperature increase in output air after two minutes with high temperature internal airflow and no external cooling airflow. Other criteria could have been selected and while probably would not alter the results of the airflow comparison, the cooling comparison would be different depending on the criteria chosen. For instance, had 60 seconds been selected as the time to record temperature rise then the AMS IC would have ranked higher in cooling performance than the other intercoolers.
Another consideration is that the tests are not being made under the same conditions that the vehicle operates. Use of these results to draw conclusions about on vehicle performance depends on the confidence each person gives to the test methods. With five product data points for the bench tests and one product data point on my GTI there isn’t sufficient information to determine how well the bench cooling test correlates with on vehicle cooling performance.