The Golf R intercooler is slightly different than the GTI intercooler. The Golf R IC is a little thicker, ~5 mm by my measurement, and has a higher fin per inch count on the external fins, approximately 11 fins per inch versus the GTI 8 fins per inch.
Testing is being performed to measure airflow through the external fins and the internal fins.
The intercooler external airflow is described in detail in this post. To summarize, the IC is placed on top of an adapter to the flow bench and the air is drawn through the external fins. The core is rotated twice with a measurement made each time so that an average airflow can be calculated. Testing is done at 10″ of H2O.
The external airflow adapter is shown in the picture in front of the intercooler.
The internal airflow is measured after attaching stock intercooler hoses to each IC end tank and placing a bellmouth at the inlet and attaching the outlet hose to the flow bench. Testing is done at 28″ of H2O.
External airflow through the Golf R intercooler is 407 CFM @ 10″ of H2O. This is shown on the chart:
The interior airflow through the Golf R IC is 237 CFM @ 28″ of H2O.
The Golf R intercooler allows 407 CFM @ 10″ of H2O through the external fins. This is the second-highest of the ten intercoolers that have been tested, trailing just the stock GTI IC.
The Golf R IC allows 237 CFM @ 28″ of H2O through the internal fins and end tanks. This is 39 CFM greater than the GTI IC and fifth highest of the thirteen stock location intercoolers that have been tested.
Note: Airflow is one characteristic I consider when comparing product options. Cooling performance is another. Both are important to me to identify a “good” intercooler. The results posted here are one part of a two-part question.