What is porting?

Porting is the technique of improving airflow by removing additional material away from a component.  Typical components are intake and exhaust manifolds, turbos, wastegates and oxygen sensor housings, all of which can be opened up to achieve better airflow.  Porting the O2 sensor housing and/or wastegate is an often recommended cure for boost creep.  This uncontrollable rise in intake pressure is often caused by the turbo pushing more air than can be possibly be dumped out of the wastegate and downpipe, despite the wastegate being completely open.

Porting is considered something of an art, with most established vendors claiming that a poor porting job will actually reduce airflow.  Some porting services also come with polishing, which some consider a waste owing to the contaminants present in exhaust air.

Many vendors offer porting services for both new and used components.