The COBB 15-20 Subaru WRX Air Oil Separator does not have enough exact application evidence to assign safe vehicle YMM. Match manufacturer part number 843615, complete vehicle, engine and transmission configuration, factory equipment, required calibration, emissions eligibility, interfaces, and every product note before ordering.

Key Features

• Billet 6061-T6 Aluminum Body: Lightweight at 1.4 lbs yet robust for track or street use, with black anodized finish and laser-etched Cobb logo.
• 4AN Nylon Braided Hoses: High-flow fittings and durable lines rated for extreme boost levels up to 30 psi.
• Integrated Check Valve: Retains full boost pressure in the crankcase while allowing oil-laden vapors to separate efficiently.
• Complete Bolt-On Kit: Includes custom bracket, all hardware, fittings, and hoses for plug-and-play fitment on VA-chassis WRX.
• CNC-machined components ensure exact fit and leak-free operation.
• Precision-machined billet 6061-T6 aluminum with black anodizing for corrosion resistance and a factory-style appearance under the hood.

Fitment

Specifications

What’s Included

One new COBB product in the exact configuration and quantity identified by manufacturer part number 843615. Calibrations, hardware, hoses, clamps, gaskets, adapters, wiring, fluids, tools, and companion components are included only when expressly stated for this exact part number.

About COBB

COBB develops engine-management, intake, cooling, exhaust, drivetrain, suspension, and vehicle-accessory products for supported performance platforms. Correct selection remains exact-vehicle, exact-configuration, exact-interface, and exact-part-number specific.

Related COBB Products

• Cobb 08-14 Subaru WRX / 08-20 STI Air Oil Separator
• Cobb 06-07 Subaru WRX / 04-07 STi Air Oil Separator
• Cobb 13-18 Ford Focus ST Air Oil Separator

Browse the COBB collection for related tuning, intake, cooling, exhaust, drivetrain, and chassis products.

Frequently Asked Questions

Why is fitment verification required for this COBB product?
Exact vehicle application evidence is not complete enough for safe YMM. Confirm the vehicle, drivetrain, factory equipment, calibration, emissions eligibility, interfaces, and exact part number before ordering.

Are all supporting parts included?
Only components expressly listed for the exact manufacturer part number are included. Tuning, hardware, hoses, clamps, gaskets, adapters, wiring, fluids, and companion components may be separate.

Is tuning or calibration required after installation?
Requirements depend on the exact product and vehicle. Intake, fuel, boost, turbo, and engine-management changes may require a compatible calibration before operation.

Installation Instructions

Follow the current COBB and factory service instructions for this exact part number. Verify fitment, factory equipment, emissions eligibility, required calibration, software and firmware, interfaces, hardware, fluid or electrical connections, and clearances before installation. Inspect the completed work and confirm safe operation before full-load use.