The Wagner Tuning intercooler for the Mk7 GTI undergoes a flow test and results in 255 CFM @ 28″ of H2O.
Wagner Competition stock location intercooler for the Mk7 GTI has been often cited as one of the best aftermarket intercoolers for the Mk7. A sample product is obtained and is subject of a flow test to compare the Wagner with the stock GTI intercooler as well as other aftermarket intercoolers that have been flow tested.
Before flow testing the Wagner intercooler the flow bench is checked with a calibration plate to ensure accurate readings are obtained.
The Wagner intercooler is then attached to the flow bench on the outlet side by using the Wagner silicone hose and an adapter that is sized to fit the outlet of the silicone hose.
On the inlet side the other Wagner silicone hose is attached and a bell mouth is inserted to facilitate smooth entry of air into the intercooler end tank.
The flow bench is then operated at a test depression of 28″ of H2O and the airflow through the intercooler system is recorded.
The Wagner Tuning Competition intercooler flowed 255 CFM @ 28″ of H2O. This result is shown on the chart along with other stock location intercoolers:
The next chart shows the Wagner intercooler compared with all types of intercoolers, and combinations of intercoolers, that have been tested:
The Wagner Tuning intercooler flows 255 CFM at the test depression of 28″ of H2O. This result is 57 CFM (roughly 29%) more than the stock GTI intercooler and the second highest airflow reading of all flow tested stock location intercoolers.
Airflow through an intercooler, which is an indicator of pressure drop, is an important value because it represents resistance that the turbocharger needs to overcome when supplying air to the engine. It is undesirable to have non value adding work being done by the turbocharger. The catch is that usually the IC generated resistance is a mechanism for improving heat transfer as the air tumbles through the IC core. The pressure drop is undesirable on one hand, and beneficial on the other. This tradeoff makes it impossible to judge an intercooler solely on the basis of air flow or cooling, both are important and optimizing them simultaneously is the challenge of good intercooler design.