Next in a bench cooling test series is a do88 Mk7 GTI intercooler. Several intercoolers that are under consideration for use on my GTI are being subjected to this test, along with a flow test, to identify candidates to install on my car for further testing.
My goal is to eventually determine the best intercooler for meeting my use criteria.
The bench cooling test involves attaching the intercooler to a flow bench to regulate airflow through the IC. At the IC outlet there is a temperature sensor placed in the air stream to record conditioned air temperature throughout the test.
At the IC inlet a pair of hot air sources are attached. A fan to supply forced air to the cooling fins is hung in front of the intercooler.
The test commences with ambient air being drawn through the intercooler without any forced cooling air supplied. The hot air is supplied for two minutes and the outlet air temperature is recorded continuously. At two minutes the fan is turned on and cooling air passes through the IC core. The outlet temperature is monitored for another minute.
The hot air supply is removed and the core is allowed to cool until it has returned to ambient temperature. The test is repeated twice to gather three data sets that are averaged.
During one test run the outlet temperature is recorded as long as it takes for the intercooler outlet temperature to begin to drop.
The chart below is a comparison of the do88 intercooler along with all of the intercoolers that have been tested thus far.
The next chart uses an expanded temperature axis to more clearly show the difference between the aftermarket intercoolers, omitting a portion of the stock GTI IC curve.
The do88 most closely resembles the result from the Unitronic test.
The extended cooling test is shown next:
The do88 intercooler is the second fastest cooling IC, trailing the Unitronic.
The do88 intercooler performs similar to the other aftermarket intercoolers during the first 40 seconds of the test. From 40-70 seconds the results mirror those of the Forge IC, and thereafter it is similar to, but slightly better than the Unitronic IC through to the two minute mark.
During the extended cooling the do88 heats more than all but the AMS IC. The do88 begins cooling during the extended phase sooner than all but the Unitronic IC.
Combining these bench cooling results along with the previous flow testing results places the do88 on the composite performance chart as shown below:
The do88 is unique among the products tested up to now by virtue of having a very high air flow and decent cooling performance. While not in the group with the lowest temperature rise ICs it does outperform the Unitronic IC that I have used with success for a while. Determining how well this intercooler performs on my GTI is something I plan to investigate.
This is a bench test. On the car the quantity and temperature of air exiting the turbocharger will exceed the conditions of the bench test. As more data is recorded on the bench and vehicle how well the two correlate should become clearer.
This test is one part of an effort to identify the “best” intercooler for my GTI. “Best” is determined by factors I consider important and these factors may not be important to other owners.
Use of this data to make conclusions about intercooler performance on a vehicle depends on the confidence each person gives to the test methods.