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.
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.
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.
The stock GTI downpipe is tested first and flows 224 CFM.
Next the USP Motorsports downpipe is tested, producing a reading of 450 CFM.
The results are compared in the following chart:
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”
Is that the two (2) piece DP from USP?
Yes. There is a link to the USP product at the intro of the post.
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.
Nice! It would be interested to see the difference between catted and cat-less options. Good job either way!
Thanks, if one becomes available I’ll test it to compare with.
Any chance you’re willing to cut up that stock DP and test using only the primary cat?
No, I’m not interested in doing that.
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