Originally Posted by
fluidmotorunion
The pipe remains at 2.75" from the MAF all the way to the manifold that connects to the turbo. Since the ID of the piping continues to decrease all the way to the turbo, to step it back up would be basically pointless. Even though the ID of our piping is exactly similar to OEM, and utilizes the OEM manifolds, if we were to try to connect these specific airboxes to the OEM MAF piping, we'd hit the hood and run into fitment issues like crazy. So as a result, to get the airflow to the levels we wanted with the airboxes we deemed best for the given application, we had to fab up our own piping of the same ID.