The factory turbo on the Nissan RB25DET quickly becomes a limitation once boost and supporting modifications increase. The Tomei ARMS MX8265 Journal Bearing Turbocharger Kit (part number TB401A-NS06A) is a complete, application-specific upgrade designed to deliver stronger mid-range response, higher peak power, and improved efficiency while remaining a true bolt-on solution for RB25DET-powered Skylines.
At the heart of the MX8265 is a CNC-machined billet compressor wheel (54.8 mm inducer / 76.2 mm exducer) produced from aerospace-grade A2618 aluminum. The lightweight billet design features thinner blades and increased surface area compared with traditional cast wheels, improving airflow and reducing rotational inertia for faster spool. The turbine side uses a high-temperature K418 alloy wheel (58.8 mm exducer / 67.0 mm inducer) paired with a 0.57 A/R housing optimized for the RB25 exhaust flange. Both compressor and turbine housings are matched at 0.57 A/R to balance response and top-end flow.
The kit utilizes a durable journal bearing center section and includes a multi-rate billet actuator that can be fine-tuned with the supplied springs, allowing precise boost control. Tomei rates the MX8265 combination for approximately 450 horsepower when paired with appropriate fueling, exhaust, and engine management. As a complete kit it includes the necessary gaskets, oil feed and return lines, studs, and hardware for a clean installation on R32, R33, and R34 RB25DET vehicles.
At Terra Firma Automotive, we supply this genuine Tomei ARMS MX8265 Journal Bearing Turbo Kit as a high-quality Japanese upgrade for enthusiasts seeking a reliable step beyond the factory turbo. It offers a strong combination of response, power potential, and bolt-on convenience for serious RB25 builds. Choose Terra Firma Automotive for authentic Tomei turbocharger systems engineered specifically for the RB25DET.
- Genuine Tomei ARMS MX8265 Turbocharger Kit
- Part Number: TB401A-NS06A
- Application: Nissan RB25DET (R32 / R33 / R34)
- Journal bearing center section
- Target power: approximately 450 hp (with supporting modifications)
- CNC billet compressor wheel (54.8 / 76.2 mm, Trim 52)
- High-temperature K418 turbine wheel (58.8 / 67.0 mm, Trim 77)
- Compressor and turbine housing A/R: 0.57
- Multi-rate billet actuator with adjustable springs
- Initial boost setting: 1.0 kgf/cm²
- Complete kit includes gaskets, oil lines, and hardware
- Bolt-on fitment for RB25DET engines
- Improved spool and mid-range response versus stock
- Strong high-RPM power potential
- Durable Japanese engineering
- Available from Terra Firma Automotive
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