COBB Air Oil Separator (843615) | Subaru WRX 2015-2021

The COBB Air Oil Separator (843615) is engineered to improve crankcase ventilation efficiency and reduce oil vapor ingestion on 2015–2021 Subaru WRX models equipped with the FA20DIT engine. By capturing oil mist before it reaches the intake system, this AOS helps maintain cleaner airflow, reduces carbon buildup, and supports long-term reliability for both stock and tuned applications.

KEY FEATURES

• Separates oil vapor from PCV gases to maintain cleaner intake tract conditions
• Helps reduce carbon deposits on valves and intake components
• Designed specifically for the FA20DIT engine and its unique PCV behavior
• Enhances long-term engine consistency under high boost and elevated temperatures
• Direct-fit installation with model-specific brackets and hose routing
• Durable construction built to withstand demanding engine bay environments

TECHNICAL SPECIFICATIONS

• Multi-stage internal design efficiently separates oil mist from crankcase gases
• Robust aluminum housing engineered for heat resistance and structural integrity
• Utilizes factory-style PCV system routing to maintain OEM engine operation
• Includes bracketry, molded hoses, fittings, and installation hardware
• Designed to improve oil control without affecting boost response or drivability

VEHICLE FITMENT

• Subaru WRX 2015–2021

COBB delivers proven, data-driven performance solutions engineered to optimize your Subaru with unmatched precision and reliability.