I am looking to upgrade the exhaust on my S4. Racing Beat has a 2.5 inch exhaust from the turbo back. Where it is a little smaller than the REVII, should I still consider porting the wastegate?
Would there be enough boost creep to require the work?
Thanks

 

If you plan on removing the catalytic converters from the system you will have to port the wastegate regardless of the larger piping or not. It sounds like your planning to do so if you want to install a full turbo back system. You should also consider getting a fuel cut defender because you will most likely increase the boost with a more free flowing system. Now, if you're keeping the catalytic converters in which they'll provide some back pressure and slow the exhaust gases you may be okay without having to port the wastegate on a 2.5 in system, but from what it seems almost everyone recommends porting the wastegate, especially on the undersized S4 wastegate.

Check out fc3spro.com, there is a lot of information there regarding what supporting mods are required on these turbo cars.