HKS 31019-AF022 Silent Hi-Power Type-S Cat-Back Exhaust System

The HKS Silent Hi-Power Type-S (31019-AF022) is a race-inspired cat-back exhaust system engineered for turbocharged applications. Drawing directly from HKS's involvement in endurance and GT racing in Japan, this system features an offset muffler and optimized piping layout designed to maximize exhaust flow by minimizing unnecessary bends for the straightest possible exhaust path.

What sets the Silent Hi-Power apart from the standard Hi-Power series is its integrated "Silent Chamber" technology. This inner silencer is built directly into the muffler body and targets low-frequency exhaust drone at cruising speeds. Because the Silent Chamber uses a closed-end design, only a minimal volume of exhaust gas enters it — meaning exhaust flow through the main system is virtually unobstructed, with no measurable performance penalty. At high RPM, the system opens up to deliver a strong, aggressive performance exhaust note.

Key Features:

• Exhaust style: HP Type-S (Silent Hi-Power)
• Primary material: SUS304 (S304) stainless steel muffler, piping, and tip assembly
• Center pipe diameter: 75mm (approx. 2.95")
• Tip outer diameter: 120mm (approx. 4.72")
• Integrated Silent Chamber reduces low-RPM cabin drone without restricting flow
• Race-inspired offset muffler design improves exhaust velocity and mid-range boost response for turbocharged engines
• High-lustre polished stainless finish for lasting appearance
• Designed for 2-door chassis configuration

The SUS304 stainless steel construction ensures corrosion resistance and a high-shine finish that holds up under sustained performance use. The Silent Hi-Power series is an ideal upgrade for enthusiasts who want meaningful power gains and an engaging exhaust note without the constant low-RPM drone of a full race exhaust.