Background:
Flow testing a sampling of Mk7 GTI compatible downpipes continues with the Trackslag catted downpipe.
Test procedure:
The flowbench is first operated with a calibration plate to ensure the measurements are accurate.
The downpipe is attached to the flowbench using a straight silicone coupler and an adapter with an expanding outlet. At the inlet of the downpipe a bellmouth is attached (not shown) to smooth the air entry into the downpipe.
The flow bench is operated at a test depression of 16″ of H2O and air is drawn in through the downpipe inlet.
Test results:
The Trackslag Mk7 downpipe with catalytic converter flows 429 CFM @ 16″ of H2O.
The chart compares this result with other downpipes that have been flow tested:
Conclusions:
The Trackslag downpipe flows 429 CFM @ 16″ of H2O which is approximately 150% more than the stock Mk7 GTI downpipe under the conditions described for this test.
The Trackslag is equipped with a large (as seen in the top picture) 200 cell catalytic converter. This catalytic converter is likely to contribute largely to the flow performance.
What did you think of the quality of the trackslag? Curious on flow of the catless version as well. Thanks for doing what you do!
It looks good to me. By no means am I an authority on welding or downpipe construction though.
I doubt the catless version would flow much differently than the CTS downpipe that I flow tested without the cat.
Thank you for the reply. I apologize I overlooked that write-up on your site. It appears a nice increase compared to catted. Thanks
Hello Jeff,
I am running my car with stage 1 APR. Planning to replace stock catalytic converter with 200 cell. Since stage 2 APR is obsolete, would it worth to use 200 cell catted downpipe with stage 1?
Thanks.
I’m just guessing, I’d be concerned about getting the cat efficiency DTC using an aftermarket catalytic converter.
What would you recommend? Leave the stock downpipe? I have a cat back installed fyi.
You might try asking APR about how their Stage 1 tune would respond to being paired with an aftermarket DP. If you try the 200 cell cat downpipe I would hang onto the stock DP in the event it doesn’t work out and you want to revert back. I think some people have had luck using an O2 sensor spacer on the DP, but I don’t have firsthand experience with that product.
In term of performance, this was their reply:
“Wan,
Not much as it is not calibrated for a downpipe.”
If this statement is valid, no point of upgrading to high flow catted downpipe.
I agree, if APR doesn’t think there’d be much benefit I would not bother.