Harness the full potential of your FA24 engine with the HKS GT-SPEC Super Manifold w/ Catalyzer. Built on decades of Japanese engineering excellence, this stainless steel equal-length exhaust manifold is designed to maximize high-RPM horsepower while maintaining strong, responsive mid-range torque for street and track use alike.

Featured in New Products Oct '25

HKS Overview Video with Sound Clups

Stainless Steel Performance & Precision

The HKS GT-SPEC Manifold embodies HKS’ long-standing exhaust development expertise. Each unit is precision-engineered from high-quality stainless steel, featuring a 4-2-1 equal-length layout that delivers superior exhaust gas scavenging and optimal flow efficiency. This manifold ensures the FA24 engine breathes freely — unlocking crisp throttle response and improved power delivery across the RPM band.

Advanced Catalyzer Design

Low-Density Metal Catalyst – Utilizes a metal catalyst with significantly lower cell density than the OEM ceramic design, drastically reducing exhaust resistance.
Optimized Metal Composition – Achieves 2018 Japanese emission compliance through optimized precious metal ratios, balancing performance with environmental standards.
Third-Party Certified – Independently tested and certified to meet strict emission control requirements.
Improved Flow Dynamics – The re-engineered flange design ensures smooth transitions and minimizes turbulence at the cylinder head.

Bypass Pipe System – Pressure Control Technology

In high-performance naturally aspirated engines, strong vacuum pulses are accompanied by intense pressure waves. HKS mitigates this with a strategically engineered Bypass Pipe System, connecting individual runners to balance pressure oscillations without affecting vacuum dynamics. This design enhances Inertia Exhaust Gas Efficiency—the ability to extract residual gases from combustion chambers—resulting in flatter torque curves, improved throttle response, and superior drivability.

4-2-1 Straight Junction Super Header Layout

Unlike traditional 4-1 race headers that sacrifice low-end torque for top-end power, HKS employs a 4-2-1 “Straight Junction” architecture that delivers real-world performance. This configuration accelerates exhaust flow through calculated pressure differentials, efficiently evacuating gases and maintaining velocity through the collector. The result is improved torque, sustained mid-range pull, and extended top-end breathing—ideal for both street and track applications.

Key Features

Stainless steel 4-2-1 equal-length manifold
Low-density metal catalyst for reduced restriction
Optimized internal gas dynamics for improved flow
Bypass pipe system for balanced pressure and torque stability
High-RPM horsepower gains without compromising drivability
Complies with Japanese 2018 emissions regulations
Direct bolt-on fitment for FA24 engines

Experience the pinnacle of naturally aspirated performance tuning with the HKS GT-SPEC FA24 Super Manifold w/ Catalyzer. Engineered for those who demand precision, reliability, and results — on the street or the circuit.

Output Characteristic Comparison

GT Manifold + HPSL2 - Max Output(kW/rpm) 160.7/6900 Max Torque (Nm/rpm) 236/4500
Stock + HPSL2 - Max Output (kW/rpm) 158.6/6800 Max Torque (Nm/rpm) 230.7/3200
Normal - Max Output (kW/rpm) Max Torque (Nm/rpm) 158/6900 228.4/3300

2022+ GR86 / BRZ Exhausts

HKS GT-SPEC FA24 Super Maifold W/ Catalyzer - 2022+ Subaru BRZ / Toyota GR86