Perrin PSP-INT-401RD 2.4in Red Silicone Turbo Inlet Hose for Subaru WRX/STI/Fore

Vehicle Fitment

• 2002-2007 Subaru WRX (EJ205, 2.0L H4 Turbocharged)
• 2004-2021 Subaru STI (EJ257, 2.5L H4 Turbocharged)
• 2004-2008 Subaru Forester XT (EJ255, 2.5L H4 Turbocharged)

Fitment Notes

• Does not fit the 2019 Subaru STI S209 - the S209 uses a different turbocharger and inlet configuration that is not compatible with this hose
• Removal of the intake manifold is not required for installation; however, access is tight and intake manifold removal may be performed to ease the process on some builds
• On 2006-2007 WRX, the hose fits close to the power steering banjo bolt line; this is a known clearance condition and does not affect function or long-term fitment
• Compatible with both stock and aftermarket intake systems - an aluminum coupler is included for use with stock airbox setups and can be omitted when using a compatible aftermarket intake
• No ECU tune or recalibration required for installation on stock or mildly modified applications; additional power gains are possible with supporting ECU tuning
• Not available for sale in California
• Sold individually - one turbo inlet hose kit per purchase

Features

• Smooth interior wall construction eliminates the restrictive pleats and corrugations found in the OEM rubber inlet hose, allowing air to flow freely into the turbocharger inlet with significantly less turbulence and restriction
• 2.4-inch inner diameter is larger than the OEM part, increasing total airflow volume to the turbocharger and reducing turbo spool time for sharper throttle response and improved mid-range acceleration
• 5-ply stainless steel wire mesh reinforcement is embedded within the silicone layers throughout the length of the hose, adding structural rigidity and preventing hose collapse under vacuum draw from restrictive filter elements or high-boost applications
• Machined aluminum BOV return insert is bonded directly into the silicone layers at the blow-off valve connection point, providing a solid, leak-free connection that eliminates the soft-wall failure common at OEM hose BOV spigots
• Glass-filled reinforced nylon coupler (rated to 400°F) joins the inlet hose to the intake system, providing a smoother air transition than metal connectors while maintaining rigidity and strength under sustained engine bay temperatures
• OEM-style plug-and-play crankcase vent diagnosis connector is the only aftermarket turbo inlet hose design to retain the factory emission control device connection without defeating or bypassing the OEM vent system
• All vacuum spigots are 1/2" inner diameter for maximum flow capacity from crankcase vents and other vacuum connections throughout the intake system
• Heat-resistant silicone construction maintains elasticity and seal integrity across the full temperature range of the engine bay, from cold starts through sustained wide-open-throttle operation and track use
• 5-year manufacturer warranty from Perrin Performance covers defects in materials and workmanship from the original date of purchase

Specifications

• Part Number: PSP-INT-401RD
• Color: Red
• Inner Diameter: 2.4 inches
• Construction: 5-Ply Heat-Resistant Silicone with Stainless Steel Wire Mesh Reinforcement
• BOV Insert: Machined Aluminum (bonded into silicone)
• Coupler Material: Glass-Filled Reinforced Nylon (rated to 400°F)
• Vacuum Spigot Inner Diameter: 1/2 inch (all ports)
• Connector Material: Glass-Reinforced Nylon (rated to 400°F)
• Tune Required: No
• Warranty: 5-Year Manufacturer Warranty

Included Components

• 1x Perrin 2.4" Red Silicone Turbo Inlet Hose (PSP-INT-401RD)
• 1x Glass-Filled Reinforced Nylon Coupler
• 1x OEM-Style Diagnosis Connector
• 1x 15-inch Vacuum Hose
• 1x Size 48 Hose Clamp
• 1x Size 36 Hose Clamp
• 1x Size 6 Hose Clamp
• 2x 1/2"-to-1/2" 90-Degree Connector
• 2x 1/2"-to-3/8" 90-Degree Connector
• 1x Perrin License Plate Frame

Product Description

The Perrin PSP-INT-401RD is a 2.4-inch red silicone turbo inlet hose engineered as a direct upgrade replacement for the factory rubber inlet hose on the 2002-2007 Subaru WRX, 2004-2021 STI, and 2004-2008 Forester XT. The OEM inlet hose uses a corrugated, pleated rubber design that creates turbulence and restriction in the airflow path between the intake filter and turbocharger inlet - a design driven by manufacturing cost rather than performance. The Perrin hose replaces this with a fully smooth interior wall, a larger 2.4-inch inner diameter, and 5-ply stainless steel wire mesh reinforcement embedded within the silicone layers. The result is a measurable improvement in airflow volume and velocity reaching the turbo inlet, translating to reduced spool time, sharper throttle response, and improved power across the RPM range without requiring any ECU tune on stock or mildly modified applications.

Where most aftermarket turbo inlet hoses require defeating or bypassing the factory crankcase vent diagnosis connector - which can trigger check engine lights or emissions issues - the Perrin PSP-INT-401RD is the only design on the market to include an OEM-style plug-in diagnosis connector that retains full factory emission system function. The machined aluminum BOV return insert is bonded directly into the silicone body at the blow-off valve connection point, eliminating the flex and potential leak path present at the OEM rubber spigot. All vacuum and vent spigots are sized at 1/2" inner diameter for unrestricted flow, and all connectors are glass-reinforced nylon rated to 400°F - engineered to hold up to sustained track use and high underhood temperatures without cracking or softening over time.

The kit includes a glass-filled reinforced nylon coupler for smooth integration with the factory airbox and compatible aftermarket intake systems, along with all hose clamps, vacuum hose, 90-degree connectors, and hardware needed for a complete installation. Intake manifold removal is not required, though the installation is a tight fit and patience is recommended. The hose is available in red (PSP-INT-401RD), black, and blue, and is backed by a 5-year manufacturer warranty from Perrin Performance. Owners of the 2019 STI S209 should note this hose is not compatible with that model's unique turbo inlet configuration.