VTT - External PCV Adapter fittingVTT External PCV Adapter fitting Adapter fitting that is required to convert your N54 to external PCV if you want to keep your crankcase under vacuum at idle, and anytime you have a vacuum condition in your intake manifold. Must be used in conjunction with our billet check valve, and PCV delete fitting or plugging of the intake PCV ports. Installs inline on the throttle body, and adds a 8AN male to adapt to our catch cans, or any custom set up. Made