Description

VTT Billet High-Flow Oil Cap Vent Adapter

For BMW Gen 2 B58TU, S58, B48 & B46 Engines

Building a high-horsepower BMW B58TU, S58, B48, or B46? As boost pressure increases, so does crankcase pressure. If that pressure isn’t properly managed, it can lead to oil leaks, excessive oil consumption, smoking, reduced ring seal, power loss, and in severe cases, engine failure.

Proper crankcase evacuation is one of the most overlooked aspects of building a reliable, high-powered turbocharged BMW. As cylinder pressure increases, so does blow-by. If the crankcase cannot evacuate that pressure efficiently, the pressure begins working against the piston rings, reducing ring seal while forcing oil vapor throughout the engine.

BMW’s factory crankcase ventilation system was designed around OEM horsepower levels and emissions requirements—not 700, 1,000, or even 2,000+ horsepower.

Through years of developing some of the world’s quickest BMWs, we’ve found that traditional -10AN vent systems quickly become a restriction on high-power builds. Even many -12AN systems begin reaching their limits as power continues to increase.

To solve this, VTT developed our Billet High-Flow Oil Cap Vent Adapter.

Precision CNC machined from billet aluminum, the adapter securely replaces the factory oil cap while providing a massive -16ORB outlet, allowing you to configure the crankcase ventilation system exactly how your build demands.

Whether you’re running upgraded factory turbos, hybrid turbos, or a full-frame single turbo conversion, this system provides substantially greater ventilation capacity than the factory PCV system while integrating seamlessly into virtually any external catch can or breather setup.

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Features

• Precision CNC-machined billet aluminum construction
• Direct replacement for the factory oil cap
• Attractive billet oil cap design
• OEM-style locking mechanism
• Fits OEM B58TU, S58, B48 and B46 valve covers
• Compatible with all VTT Billet and Cast Valve Covers
• Integrated internal oil separation passages designed to reduce large oil droplets before entering the catch can
• Large -16ORB outlet
• Supports vent sizes from -12AN through -20AN
• Compatible with virtually any catch can or atmospheric breather system
• Designed specifically for high-horsepower turbocharged BMW engines

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Why Upgrade?

As horsepower increases, so does crankcase pressure.

If that pressure isn’t evacuated efficiently, it can contribute to:

• Excessive oil consumption
• Oil leaks
• Smoking under boost
• Reduced piston ring seal
• Increased crankcase pressure
• Reduced engine efficiency
• Inconsistent performance
• Increased stress on engine seals

Increasing crankcase ventilation capacity allows the engine to evacuate blow-by more effectively while helping maintain crankcase stability during high boost and sustained high-RPM operation.

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Available Fitting Options

Choose the configuration best suited for your build.

Straight Fittings

• -16ORB to -12AN Male (17.4mm Hose ID)
• -16ORB to -12AN Male with 1/8″ NPT Sensor Port
• -16ORB to -16AN Male (22.2mm Hose ID)
• -16ORB to -16AN Male with 1/8″ NPT Sensor Port
• -16ORB to -20AN Male (28.5mm Hose ID)

Low Profile Fittings

• 90° Low Profile -12AN Male
• 90° Low Profile -16AN Male

Ideal where hood clearance is limited.

Optional Check Valve

-16AN One-Way Check Valve

Maintains crankcase vacuum during idle and light throttle operation while allowing unrestricted crankcase evacuation during boost.

(Additional fittings may be required depending on your installation.)

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Vehicle Compatibility