The next Mk7 GTI intercooler to undergo testing is the stock location replacement made by Mishimoto. The purpose of the test is to generate data under well controlled conditions that can be used to compare different IC options for the Mk7 GTI.
The bench cooling test does not replace testing on the Mk7 GTI, but provides information about the heat exchanger performance that can be used along with data gathered through other means to assess the various products available.
Briefly recapping the bench cooling test, the Mishimoto intercooler will be attached to the flow bench to help regulate hot airflow through the IC. A pair of hot air sources (heat gun and hair dryer) will supply air to the IC inlet, and at the IC outlet there is a temperature sensor that displays the output air temperature.
Air is run through the core for 2 minutes after which a cooling fan is turned on to force air through the IC cooling fins. The temperature continues to be monitored for one more minute.
The results of the Mishimoto cooling test are shown below along with the stock GTI intercooler.
The Mishimoto IC cools the outlet air significantly more than the stock intercooler for the period of evaluation.
The next chart compares the Mishimoto intercooler with all of the other intercoolers that have been tested up to now.
Looking more closely at the results by scaling the temperature axis to exclude a portion of the stock IC results:
Adding the Mishimoto temperature performance, along with previous flow testing results, to the composite performance chart:
The Mishimoto intercooler output air temperature at the conclusion of the bench cooling test is the lowest of all of the intercoolers that have been tested up to now.
The bench cooling test so far has looked at how the different intercoolers compare over a three minute time period with hot air being flowed through the intercooler.
Data was recorded for some of the intercoolers for a longer period of time after the heat source was removed at 180 seconds. At 180 seconds the heat source was removed and the flow bench continued to pull outside air through the IC with the cooling fan continuing to push air through the cooling fins. This was done to observe when the output temperature would begin to drop. The extended measurements are shown on the next chart:
The data line ends when the first reading is taken showing the outlet air temperature decreasing.
For example, the outlet air temperature from the AMS intercooler begin to increase at approximately sixty seconds into the test. The temperature continues to increase and peaks at 240 seconds into the test at approximately 31.5F degrees above the starting temperature. The next sample reading at 250 seconds indicates the outlet temperature has gone down to 31F. Because the temperature has begun to decrease the data line is stopped at 250 seconds.
This phase of the test might (emphasis on might because at this point it is just speculation) give some insight into how well each of the intercoolers recovers after a boost event on the GTI.
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 obtained during 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 six 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.