Mk7 GTI Stock Downpipe Flow Test

Downpipe Flow Test

Background:

With a downpipe exchange in process there are a pair of downpipes available to conduct a flow test. The products are a stock Mk7 GTI downpipe and a USP catted downpipe.

Test Procedure:

Each downpipe is connected to a flow bench using a straight silicone coupler hose. There is a bellmouth attached to the inlet end of the downpipe.

USP Downpipe Bellmouth
USP Downpipe Bellmouth

The flow bench is operated at a test depression of 28″ of H2O and the airflow at this pressure is recorded.

The USP downpipe has a reducer attachment at the outlet end to connect to the stock GTI exhaust.

USP Exhaust Reducer Coupler
USP Exhaust Reducer Coupler

Test Results:

The stock GTI downpipe is tested first and flows 224 CFM.

Mk7 GTI Stock Downpipe Flow Test
Mk7 GTI Stock Downpipe Flow Test

Next the USP Motorsports downpipe is tested, producing a reading of 450 CFM.

USP Downpipe Flow Test
USP Downpipe Flow Test

The results are compared in the following chart:

Mk7 GTI Downpipe Flow Test
Mk7 GTI Downpipe Flow Test

Conclusion:

The USP Motorsport catted downpipe flows approximately double the airflow of the stock GTI downpipe at the test depression of 28″ of H2O.

8 thoughts on “Downpipe Flow Test”

  1. Jeff,

    Thanks for the reply! I have the same DP. I love your site. You pretty much test everything that I want to do to my MK7 Golf. Keep up the great work.

    John

  2. Nice! It would be interested to see the difference between catted and cat-less options. Good job either way!

  3. Any chance you’re willing to cut up that stock DP and test using only the primary cat?

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