Another product from White Dog Racing was sent to me for flow testing and comparison to the White Dog Racing bipipe products that I previously flow tested, along with the few other Audi B5 S4/RS4 bipipe options.

This time I received a 60 mm bipipe with RS4 throttle body.

I was interested to see how much of a difference adding the RS4 throttle body would make to the flow performance of the 60 mm WDR bipipe versus the S4 throttle body that was used with the prior tests, and also compared to the full RS4 intake setup.

Results:

 

The flow through the WDR-60/RS4 product far surpassed that of all the other bipipe combinations I have flow tested thus far.

Curious about how the flow would be affected by adding the silicone adapter/couplers to the inlet of the pipe, I compared three setups: bare metal, a 2.5″ coupler, and a 2.5″ to 2.25″ hump hose coupler.

Results of these three cases measured at 16″ of H2O were:

The addition of the 2.5″ coupler improved airflow measurably.  The reduction from 2.5″ to 2.25″ caused a small decrease in airflow.

Conclusion:

The White Dog Racing 60mm bipipe combined with the RS4 throttle body has achieved the highest airflow through a bipipe / throttle body combination that I have measured.