IAG Stage 1 Blueprinted 11mm Oil Pump 2002-2014 WRX / 2004-2021 STI / 2005-2012 Legacy GT / 2005-2009 Outback XT / 2004-2013 Forester XT

The IAG Stage 1 Blueprinted EJ25 11mm Oil Pump is designed to fit all Subaru EJ series engines, including both single and dual AVCS applications. It is an ideal choice for stock or mildly built IAG 550 engines used in street-driven vehicles, delivering dependable oil pressure and long-term reliability. Each pump is fully measured, blueprinted, assembled, and shipped pre-lubed with assembly lubricant, making it ready for installation right out of the box with all required hardware included.

The oil pump is the heart of the engine, responsible for circulating oil throughout the entire system. Despite its critical role, oil pump quality is often overlooked. Through extensive experience, IAG has found that even brand-new OEM Subaru oil pumps can suffer from assembly inconsistencies, including improper hardware torque and rotor clearances that fall outside of specification. These issues can lead to reduced oil pressure and, in severe cases, costly engine damage.

To address these concerns, the IAG Stage 1 Blueprinted EJ25 11mm Oil Pump improves upon the factory design through careful inspection, refinement, and precise assembly. Each pump undergoes a comprehensive inspection process to ensure the rotor clearances, pressure relief valve operation, and internal hardware are all within proper tolerances. The pump is also modified to increase oil pressure, helping to maintain consistent oil delivery under demanding conditions.

Every Stage 1 pump begins as a brand-new OEM Subaru 11mm oil pump. It is completely disassembled and inspected for debris or contaminants, then ultrasonically cleaned to remove any impurities. The pressure relief valve piston is REM polished to achieve a low surface roughness, reducing friction and minimizing the risk of galling or sticking in the bore—an issue commonly found even in new factory pumps. After polishing, the piston is reinstalled and verified for proper operation.

The rotors are carefully measured and confirmed to be within manufacturer specifications before installation. During final assembly, all components receive a light coating of assembly lubricant to aid priming on initial startup and reduce friction. The backing plate is installed using Loctite on the hardware, each fastener is properly torqued, and final torque verification marks are applied.