AMS Performance EJ25 Intake Manifold Uncoated (AMS.31.08.0001) | Subaru 2002-2014 WRX / 2004-2021 STI

The AMS Performance EJ25 Intake Manifold Uncoated is engineered to maximize airflow efficiency and intake performance for Subaru WRX 2002–2014 and Subaru STI 2004–2021 applications equipped with EJ25 engines. Developed using advanced CFD modeling and extensive real-world testing, this intake manifold is designed to support high-horsepower street, track, and motorsports builds where consistent airflow distribution, cylinder balance, and top-end power are critical.

KEY FEATURES

• High-performance intake manifold designed specifically for Subaru EJ25 engines
• Large-volume plenum and equal-length runners optimize airflow distribution
• CNC-machined billet bellhorns function as internal velocity stacks
• Uncoated finish allows for custom thermal coating or polishing
• Engineered for high-horsepower, boosted, and competition-level applications

TECHNICAL SPECIFICATIONS

• Component Type: Intake manifold
• Engine Compatibility: Subaru EJ25
• Plenum Volume: 4.5 liters
• Runner Length: 13 inches (equal length)
• Runner Diameter: 2.5 inches (63.5 mm) tapered
• Bellhorn Design: CNC-machined billet velocity stacks
• Throttle Body Compatibility: Accepts up to 70 mm throttle body with mild porting
• Finish: Uncoated (raw)
• Performance Data: Manufacturer testing has shown gains of up to approximately 51 wheel horsepower in select high-performance builds

VEHICLE FITMENT

• Subaru WRX 2002–2014
• Subaru STI 2004–2021

PRODUCT NOTES

• Not compatible with top-mount intercooler configurations due to runner design.
• May require mild clearancing of the A/C compressor line on certain 2008+ STI models.
• Some port matching may be required when used with CNC-ported or hand-ported cylinder heads.
• Standard intercooler piping may require custom fabrication depending on throttle body orientation.
• Reverse throttle body orientation requires alternator relocation, A/C compressor removal, and custom intercooler piping.
• Requires aftermarket top-feed fuel rails and lines; factory fuel rails and side-feed injector systems are not compatible.

AMS Performance engineers race-proven performance components and systems designed to deliver measurable power gains, reliability, and repeatable results for street, track, and motorsports applications.