This HKS Evo X catback was developed to improve your torque and horsepower. Full (75mm) 2.9 inch cat-back with a great deep throaty sound. Adds HP and increased throttle response. Piping is mandrel bent with a stainless steel muffler and includes a bung for the 02 sensor. Sound: Low deep growling sound. Provides a loud tone under acceleration, moderately quite at idle. TECH TIP: Direct bolt on, includes EVERYTHING for an easy installation. NO other modifications needed. Bolts up to the existing stock exhaust hangers.
To maintain the exhaust efficiency, enlargement of the exhaust pipe is usually required; the sound level tends to be increase and low-tone. The exhaust system with a cannon ball-shaped shell usually has lower silencer capacity than an oval-shaped shell; therefore, to reduce the sound level, the pipe diameter is narrowed. However, a narrow pipe diameter also reduces the exhaust efficiency and increase the exhaust pressure.
HKS utilized original unique technology to maintain the exhaust capacity and sound level to meet the JASMA standard which is more severe than the regular safety standard. Inner structure of the silencer was redesigned so the unwanted low exhausts resonance was eliminated, and the sound quality was improved.