2023–2025 Honda Civic FL5 Helix Air Oil Separator

Overview

Modern turbocharged engines recirculate crankcase blowby gases back into the intake tract through the factory PCV system. While effective for emissions control, these gases also carry oil vapor, fuel, and moisture that can accumulate in the intake manifold over time. These contaminants contribute to carbon buildup on intake valves, reduce effective fuel octane, and increase the likelihood of detonation. The PRL Helix Air Oil Separator is designed to remove these contaminants before they are reintroduced into the intake system, helping maintain a cleaner intake path and more consistent engine operation without venting metered air or altering factory drivability.

At the core of the PRL AOS is a proprietary internal helix that creates controlled centrifugal motion within the canister. As blowby gases enter the system, heavier oil droplets, fuel, and moisture are forced outward toward the walls of the can, where they condense and collect at the bottom. The cleaned air is then routed back into the intake system, ensuring closed loop operation and preserving proper fueling behavior. The system is fully serviceable and must be drained at regular intervals, with service frequency depending on climate and driving conditions.

Each PRL Helix AOS is designed and produced in house using CNC machined 6061-T6 billet aluminum and finished with a durable hard anodized coating. The canister is available in both Black and Silver anodized finishes and is paired with a laser cut and CNC bent 304 stainless steel mounting bracket. Custom molded reinforced rubber hoses, billet aluminum fittings, a billet check valve, and Viton O-rings are used throughout the system to ensure long term durability, chemical resistance, and a clean OEM style installation suitable for the FL5 engine bay.

Quick Specs

• CNC machined 6061-T6 billet aluminum canister with hard anodized finish
• Available in Black or Silver anodized options
• Proprietary internal helix separation design
• Custom billet aluminum fittings and billet check valve
• Viton O-rings for superior durability and chemical resistance
• NBR reinforced rubber hoses designed for engine bay environments
• 304 stainless steel laser cut and CNC bent mounting bracket
• Retains closed loop operation and does not interfere with emissions equipment

Fitment

• 2023–2025 Honda Civic Type-R (FL5)

What’s Included

• PRL Helix Air Oil Separator canister
• Stainless steel mounting bracket
• Custom molded hose set
• Billet fittings and check valve
• All required clamps and installation hardware

INSTALL GUIDE