Product Fitment:
2002-2007 Subaru WRX
2004-2021 Subaru STI
The Tomei ARMS BX8265 Ball-Bearing Turbocharger Kit is a high-performance turbo upgrade designed for Subaru EJ20 and EJ25 single-scroll engines. Engineered to deliver fast spool and strong top-end power, this turbo uses advanced materials and precision manufacturing to provide reliable performance for both street and track builds targeting up to approximately 450 horsepower with proper supporting modifications.
At the heart of the BX8265 is a CNC-machined billet aluminum compressor wheel made from aerospace-grade A2618 material. The lightweight design and thinner blades improve airflow efficiency and help the turbo spool faster compared to traditional cast compressor wheels.
For precise boost control, the turbo features a multi-rate billet wastegate actuator with interchangeable springs. Multiple springs can be combined to fine-tune boost pressure for your specific setup, giving tuners the flexibility needed for performance builds.
Designed for Subaru EJ-series engines with single-scroll turbo configurations, the ARMS BX8265 offers improved airflow capacity, durability, and consistent boost response for enthusiasts seeking stronger mid-range torque and high-RPM performance.
Key Features
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Ball-Bearing Turbocharger Design for improved response and durability
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CNC Billet A2618 Compressor Wheel for increased airflow and faster spool
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Multi-Rate Billet Wastegate Actuator with included springs for adjustable boost control
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Designed for EJ Single-Scroll Turbo Applications
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Supports Up To Approximately 450 HP with proper supporting modifications
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High-Strength Turbine Materials for durability under extreme heat and boost conditions
Turbocharger Specifications
| Specification | Details |
|---|---|
| Turbo Model | ARMS BX8265 |
| Bearing Type | Ball Bearing |
| Target Power | ~450 HP |
| Initial Boost Setting | 1.0 kgf/cm² |
| Compressor Wheel | 54.8mm Inducer / 76.2mm Exducer |
| Compressor Trim | 52 |
| Compressor Material | CNC Billet A2618 Aluminum |
| Turbine Wheel | 58.8mm Exducer / 67mm Inducer |
| Turbine Material | Cast K418 |
| Compressor Housing A/R | 0.78 |
| Turbine Housing A/R | 0.57 |
| Scroll Type | Single Scroll |
Performance Overview
The Tomei ARMS BX8265 is engineered for enthusiasts looking for a balanced turbo upgrade that delivers strong horsepower gains while maintaining responsive spool characteristics. With its billet compressor wheel, ball-bearing center section, and adjustable wastegate actuator, this turbocharger provides a dependable solution for Subaru EJ performance builds targeting the 400–450 horsepower range.