The Brief
The owner wanted more sound and more power from his FL5 Type R without going overboard. The factory exhaust is quiet for what the car is, and the K20C1 has proven headroom for a clean tune. The goal was a catback exhaust with proper titanium tips and a custom dyno tune to extract what the factory leaves on the table.
The Approach
We went with the HKS Legamax Sports catback for the exhaust. It’s a well-engineered system with a proper tone that suits the FL5 without being obnoxious. The titanium tips look the part sitting in the factory diffuser and the build quality is what you’d expect from HKS. For the tune side, the FL5 ECU needs to be jailbroken before Hondata FlashPro can communicate with it. This is a one-time procedure that opens the ECU for reflashing, allowing full access to fuel, ignition, cam timing, and boost targets through the FlashPro interface.
The Build
The factory catback was removed and the HKS Legamax Sports system went in. Straightforward swap that bolts up to the factory mid-pipe. With the exhaust sorted, we moved to the ECU. The jailbreak process was completed to unlock the FL5’s ECU for FlashPro access. From there, the car was tuned on our Dynapack with a custom calibration optimising fuel delivery, ignition timing, cam phasing, and boost targets on 98 octane. The tune was built around daily reliability with a focus on better throttle response and extracting the power the factory tune leaves on the table.
The Result
The Legamax Sports gives the K20C1 a deeper, more aggressive tone under load while staying refined at cruise. The active exhaust valve integration means it’s still quiet when you want it to be. The custom tune cleans up the factory fueling and ignition tables, with improved throttle response, smoother power delivery, and stronger pull through the mid-range.
