Perrin Front Mount Intercooler Boost Tube Kit Black 2015-2021 STI | 2.25” to 2.75” Diameter | Aluminum Boost Tubes

Overview

The Perrin Front Mount Intercooler Boost Tube Kit is designed specifically for the 2015-2021 Subaru WRX STI, offering a direct upgrade to the factory boost tube system. This kit replaces restrictive OEM piping with CNC mandrel bent aluminum tubes that optimize airflow from the turbocharger through the intercooler to the throttle body. It’s ideal for STI owners looking to reduce pressure drop, improve boost response, and unlock additional power potential without the need for immediate ECU tuning.

Engineered with precision, the boost tubes feature a smooth, mandrel-bent design that minimizes turbulence and maximizes airflow efficiency. The tubes increase in diameter from 2.25 inches at the turbo outlet to 2.75 inches near the intercooler and throttle body, ensuring unrestricted air movement. Powder-coated in black, these tubes resist corrosion and maintain a clean, OEM+ appearance. The kit also includes custom CNC-machined aluminum brackets and upgraded coolant and washer fluid tanks to accommodate the new routing, reflecting Perrin’s commitment to quality and functional design.

By improving charge air cooling and reducing pressure losses, this boost tube kit delivers proven gains of 10 to 20+ wheel horsepower across various power levels. The design maintains OEM clearance for easy installation and compatibility with other modifications. STI owners benefit from enhanced throttle response and more consistent boost delivery, making this an essential upgrade for both street and track applications.

Features & Specifications

This Perrin Front Mount Intercooler Boost Tube Kit is engineered for the 2015-2021 Subaru WRX STI and features a progressive diameter design from 2.25” to 2.75”. Constructed from lightweight aluminum with a durable black powder coat finish, it delivers improved airflow and boost efficiency for Subaru enthusiasts seeking reliable power gains without mandatory tuning.

• Brand: Perrin Performance
• Product: Front Mount Intercooler Boost Tube Kit Black
• Part Number: PSP-ITR-438-3BK
• Fitment: 2015-2021 Subaru WRX STI
• Material: Aluminum
• Finish: Black powder coat
• Construction: CNC mandrel bent tubing
• Origin: USA (Perrin Performance)
• Tube Diameter: 2.25” (turbo outlet) to 2.75” (intercooler/throttle body)
• Included Tanks: Aluminum coolant overflow and washer fluid tanks
• Mounting: CNC-machined direct-mount aluminum brackets
• Power Gains: +10 to 20+ Wheel HP (dyno proven)
• Tuning Required: No (tuning recommended for additional gains)

Key Benefits

• Performance: Reduces boost pressure drop for improved throttle response and power delivery
• Durability: Powder-coated aluminum resists corrosion and maintains appearance over time
• Fitment: Designed specifically for 2015-2021 STI with OEM clearance for hassle-free installation
• Quality: CNC mandrel bending ensures smooth airflow and structural integrity
• Value: Adds significant horsepower gains without requiring immediate ECU recalibration
• Completeness: Includes upgraded coolant and washer tanks for proper boost tube routing

What's Included

• 1× Perrin Front Mount Intercooler Boost Tube Kit Black
• 1× Perrin Aluminum Coolant Overflow Tank (powder coated)
• 1× Perrin High Capacity Aluminum Washer Fluid Tank
• Direct-mount CNC-machined aluminum intercooler brackets
• All necessary mounting hardware
• Installation instructions

Installation & Compatibility

Installation of the Perrin Boost Tube Kit is moderately straightforward for enthusiasts with basic mechanical skills and common hand tools. The kit is designed for direct bolt-on fitment with no permanent modifications required. The included coolant and washer tanks simplify routing and clearance issues commonly encountered with larger diameter piping. While no ECU tuning is required to safely run this kit, proper tuning is recommended to maximize power gains and ensure optimal engine performance. Always verify compatibility with your specific STI model year and any other aftermarket modifications installed.

• Professional Installation: Recommended for best results
• Modifications Required: None
• Verify Compatibility: Confirm fitment for 2015-2021 Subaru WRX STI

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