The HKS Legamax Sports Exhaust System (Part No. 31021-AH005) is a premium cat-back upgrade designed specifically for the 2022+ Honda Civic Type R FL5 equipped with the K20C1 engine.
This system enhances performance, sound, and aesthetics while maintaining compatibility with the vehicle’s factory systems.
Key Features
- Performance Enhancement: The exhaust system features a 75mm full straight design that reduces exhaust pressure by approximately 30% compared to the stock setup. This reduction in backpressure improves exhaust efficiency and can lead to performance gains, especially when paired with ECU tuning solutions like the HKS Power Editor.
- Valveless Design with Actuator: Unlike the stock exhaust, which includes a valve mechanism, the Legamax Sports system adopts a valveless design to optimize exhaust flow. To prevent potential error codes due to the absence of the valve, HKS includes a dedicated actuator that replicates the stock valve’s function, ensuring seamless integration with the vehicle’s electronics.
- Distinctive Sound: The system delivers a sporty exhaust note that is more pronounced than stock (93 dB compared to 84 dB) without causing discomfort during regular driving. The sound tuning eliminates unpleasant muffled tones, providing a clear and engaging auditory experience.
- Premium Materials and Design: Constructed from high-quality stainless steel (S3/S4L), the exhaust features dual 119mm titanium tips engraved with the HKS logo. The design not only enhances durability but also adds a visually striking element to the vehicle’s rear profile.
- Compliance and Certification: The exhaust system is certified under JQR30233117, ensuring it meets specific regulatory standards.
Technical Specifications
- Vehicle Compatibility: Honda Civic Type R FL5 (2022+)
- Engine: K20C1
- Main Pipe Diameter: 74.7mm transitioning to dual 60.5mm
- Tip Diameter: 119mm
- Material: S3/S4L Stainless Steel with Titanium Tips
- Weight: Approximately 18.5 kg
- Ground Clearance: Approximately 125mm from the factory front under panel
- Noise Level: 93 dB (HKS) vs. 84 dB (Stock)
HKS LEGAMAX SPORTS FOR HONDA CIVIC TYPE R FL5 K20C 31021-AH005










