Perrin Front Mount Intercooler Boost Tube Kit - Red - 2015-2021 STI

Perrin Front Mount Intercooler Boost Tube Kit Red 2015-2021 STI | 2.25"-2.75" Diameter | Performance Boost Tubes

Overview

The Perrin Front Mount Intercooler Boost Tube Kit is designed specifically for the 2015-2021 Subaru WRX STI, delivering improved airflow and enhanced boost efficiency. This kit replaces the restrictive OEM boost tubes with larger diameter, smooth mandrel-bent aluminum tubes that optimize the path of compressed air from the turbocharger to the intercooler and throttle body. It’s ideal for STI owners looking to maximize their vehicle’s power potential without compromising reliability or requiring immediate ECU tuning.

Engineered with precision, the boost tubes feature a stepped diameter design—2.25 inches from the turbo outlet expanding to 2.75 inches near the intercooler and throttle body—to reduce pressure drop and turbulence. The CNC mandrel bending ensures smooth airflow transitions, while oversized beaded ends secure silicone couplers firmly at any boost level. The kit also includes custom CNC-machined aluminum intercooler brackets, a high-capacity washer fluid tank, and a powder-coated coolant overflow tank to maintain proper clearance and fitment around OEM components.

By improving charge air cooling and reducing intake restriction, this kit has been dyno-proven to add 10 to 20+ wheel horsepower across various power levels. The design balances performance gains with ease of installation and durability, making it a practical upgrade for Subaru WRX STI enthusiasts who want reliable power improvements without immediate tuning. For those pursuing further modifications, additional gains can be unlocked with proper ECU recalibration tailored to the full setup.

Features & Specifications

This Perrin Front Mount Intercooler Boost Tube Kit is engineered for the 2015-2021 Subaru WRX STI and features stepped boost tube diameters from 2.25" to 2.75". Constructed from lightweight CNC mandrel-bent aluminum, it delivers improved airflow and boost efficiency for Subaru enthusiasts seeking reliable power gains and OEM-level fitment.

• Brand: Perrin Performance
• Product: Front Mount Intercooler Boost Tube Kit Red
• Part Number: PSP-ITR-438-3RD
• Fitment: 2015-2021 Subaru WRX STI
• Material: CNC Mandrel-Bent Aluminum
• Finish: Powder Coated Red
• Construction: CNC Machined, Mandrel Bent Tubing
• Origin: Made in USA
• Boost Tube Diameter: 2.25" (Turbo Outlet) to 2.75" (Intercooler/Throttle Body)
• Included Tanks: Powder Coated Coolant Overflow Tank, 6061 Aluminum High Capacity Washer Fluid Tank
• Mounting: CNC Machined Direct-Mount Aluminum Brackets
• Power Gains: +10 to 20+ Wheel HP (Dyno Proven)
• Tuning Required: No tuning required for stock ECU, tuning recommended for additional gains

Key Benefits

• Performance: Increased airflow reduces pressure drop, improving turbo efficiency and power delivery.
• Durability: CNC mandrel-bent aluminum tubes resist cracking and deformation under boost pressure.
• Fitment: Designed for direct bolt-on installation with custom brackets and tanks to maintain OEM clearance.
• Cooling Efficiency: Improved charge air cooling supports consistent performance during spirited driving or track use.
• Appearance: Powder-coated red finish adds a clean, performance-oriented look under the hood.
• Value: No immediate ECU tuning required, allowing power gains without additional expense or complexity.

What's Included

• 1× Perrin Front Mount Intercooler Boost Tube Kit Red
• 1× Powder Coated Coolant Overflow Tank
• 1× 6061 Aluminum High Capacity Washer Fluid Tank
• 1× Set of CNC Machined Direct-Mount Aluminum Intercooler Brackets
• Mounting hardware and silicone couplers
• Installation instructions