An XS-Power bipipe was delivered a few days ago to go into the Get Healthy Silver S4 that I’m currently working on.   Since the product has not been flow tested, and this one is available, I decided to stick it onto the flowbench and see how it performs.

The XS-Power bipipe intake diameter is 51 mm on the inside of the pipe.  Here is how this compares to the other alternative bipipes I have measured the inlet size of:

• APR:  49.8 mm
• WDR-54:  52.4 mm
• WDR-60:  59.3 mm
• RS4:  61.1 mm

I tested the XS-Power Bipipe with a Stock B5 S4 Throttle Body at 28″ of H2O and recorded a CFM of 545.  This compares to some of the other bipipe options as follows:

Peak airflow ranking correlates with the inlet diameter, the XS-Power bipipe places just above the APR bipipe and a little below the WDR-54 bipipe.

With the APR bipipe being discontinued the XS-Power bipipe presents a new option that is similar in design as well as performance.

In the past I’ve noted that different results occur when the inlet hoses are connected to the bipipes.  The comparison above is using just the bipipe without an inlet hose.

To illustrate how the inlet hose alters the airflow through the bipipe a comparison with and without the inlet coupler hose is shown below:

The APR bipipe shows the greatest increase in airflow with the coupler hoses attached, having a maximum airflow equivalent to the XS-Power bipipe within the measurement margin of error.  All of the bipipes see a reasonable gain in airflow when the Intercooler coupler hose is attached to the end of the bipipe.