Code No. 33005-AT014
Outstanding purification performance that meets emissions regulations while improving exhaust flow efficiency.
Catalyst Cell Density Comparison
■Features
- By utilizing a 150-cell catalyst substrate in place of the factory 600-cell catalyst, the HKS Metal Catalyzer achieves approximately 40% lower exhaust back pressure compared to stock.
- The outlet section features a dedicated lost-wax cast design optimized for maximum flow efficiency and is finished with an engraved HKS logo.
- Extensive in-house testing was conducted in accordance with the Japan 2018 Emissions Regulations (WLTC cycle), and official certification has been obtained through an authorized testing agency, providing confidence and peace of mind for street use.
■Contents
| Material | SUS304 Stainless Steel |
| Catalyst Spec | 150-Cell |
| Pipe Diameter | 85mm |
| Sound Level (Stock Catalyst) |
with Stock Muffler: 84dB (Idle: 58dB) with Super Turbo Muffler: 89dB (Idle: 60dB) |
| Sound Level (HKS METAL CATALYZER) |
with Stock Muffler: 88dB (Idle: 60dB) with Super Turbo Muffler: 90dB (Idle: 62dB) |
| Catalyst Weight | 6.43 kg (Stock: 5.12 kg) |
■Performance
Improved exhaust flow efficiency results in gains of up to 7 kW (10 PS) in power and 11 N·m (1.1 kgf·m) in torque. In addition, both power and torque show significant improvements over the factory catalyst throughout the 3,000–6,000 rpm range. These gains contribute to improved drivability and enhanced overall engine response in everyday driving as well as spirited performance applications.
| Max. Power [kW/(PS)pm] | Max. Torque [Nm(kgf･m)/rpm] | |
| HKS METAL CATALYZER + Stock Muffler | 291.5(396.3)/6,100 | 552.2(56.3)/3,800 |
| Stock Catalystic + Stock Muffer | 284.6(386.9)/6,600 | 541.5(55.2)/3,100 |
*Graphs and values are based on in-house testing.
Results may vary depending on vehicle condition and test equipment.
■Layout Comparison
A dedicated lost-wax outlet design, reduced catalyst cell density, and optimized pipe diameter and routing combine to maximize backpressure reduction.
■In-House Test Data
The optimized catalyst substrate reduces backpressure by 40%, making it an effective component for future power upgrades such as increased boost pressure.
| Exhaust Sound Level [dB] | Idle Noise Level[dB] | |
| HKS METAL CATALYZER ＋ STM | 94 | 62 |
| HKS METAL CATALYZER + Stok Muffler | 88 | 60 |
| Stock Catalystic + Stok Muffler | 84 | 58 |
*Graphs and values are based on in-house testing and may vary depending on vehicle condition, equipment, and operating conditions.
*Test engine speed: 3,750 rpm.
- Frequency analysis during close-proximity noise testing shows stronger 300 Hz and 600–700 Hz bands than the stock catalyst, producing a higher-pitched exhaust note.
- Frequencies above 300 Hz and low-frequency tones below 200 Hz are emphasized, creating a more powerful and engaging exhaust sound.
- Combined with the Super Turbo Muffler (31029-AT007), measured close-proximity exhaust noise is 94 dB, remaining within legal limits.
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