Background:
Several months ago, I posted a flow test of the CC Design 4″ GESi catted downpipe. This part was en route to my Golf R, where it would be replacing an AWE Tuning HJS catted downpipe.
With the swap completed, the AWE Tuning downpipe was available for flow testing.
Test setup:
The downpipe would be attached directly to the flow bench, and a bellmouth adapter would be installed at the inlet to smooth airflow into the downpipe.
The flow bench would be operated at a depression of 16″ of H2O, and the airflow rate through the downpipe would be recorded.
Test results:
The AWE Tuning downpipe flows 231 CFM @ 16″ of H2O. This is shown on the graph along with all other dowpipes that have been flow tested.
The AWE Tuning downpipe is on the lower end of the downpipes tested. To some extent, this is expected, since a number of the products tested were catless, and others use high-flow catalytic converters that do not perform sufficiently to prevent a CEL for catalyst inefficiency—something that the catted AWE downpipe is designed to address.
The piping is also smaller than the CC Design downpipe it was replaced by, and I was curious to see if the different downpipes would produce different performance from the car.
Street Test:
With the CC Design downpipe on the car, and a number of logs made with the AWE Tuning, I just needed to log the R and see how it compares with the previous logs.
Notably, the last time I logged the Golf R with the AWE Tuning downpipe under similar environmental conditions was almost 2 years ago; therefore, I cannot be confident that no other factors contributed to the logged outcome.
Boost pressure and turbocharger wastegate duty are reasonably similar, with the AWE Tuning downpipe showing a slight increase in wastegate duty cycle.
Evaluating the acceleration data with Virtual Dyno shows an estimated average increase of 45 whp.
This difference is large enough to be statistically significant, but with only two data points, the comparison lacks the power to detect the effect, even with a large difference of means values:
The bottom line is that there is some indication that the car is accelerating more quickly with the CC Design downpipe, but there is insufficient data to rule out distortion caused by random or systematic errors.
Conclusion:
The AWE Tuning catted downpipe for the Mk7 was flow tested and compared with other downpipes available for the Mk7.
The AWE Tuning downpipe flows 231 CFM @ 16″ of H2O.
This measure is on the low end of the downpipes which have been flow tested, a collection that consists of products that are catless and ones with a 200-cell-per-inch catalyst, both of which are inadequate to prevent the triggering of a cat inefficiency code, something the AWE downpipe is designed to avoid.
A street comparison with a higher-flowing downpipe was inconclusive but suggested the higher-flowing product yielded greater peak horsepower.