ACL 4B8325H-STD Race Rod Bearing Set Standard Subaru FB20 FB25 Forester Impreza

Vehicle Fitment

• 2011-present Subaru Forester (SH/SJ/SK) - FB20 2.0L and FB25 2.5L DOHC Boxer-4 (Naturally Aspirated)
• 2012-2016 Subaru Impreza (GP/GJ) - FB20 2.0L DOHC Boxer-4
• 2017-present Subaru Impreza (GT) - FB20 2.0L DOHC Boxer-4
• 2013-2017 Subaru XV / XV Crosstrek (GP) - FB20 2.0L DOHC Boxer-4
• 2018-present Subaru Crosstrek (GT) - FB20 2.0L DOHC Boxer-4
• 2010-present Subaru Legacy (BM/BN/B4) - FB25 2.5L DOHC Boxer-4
• 2010-present Subaru Outback (BR/BS/BT) - FB25 2.5L DOHC Boxer-4
• 2015-2021 Subaru WRX (VA) - FB20B 2.0L DOHC Turbo Boxer-4 (confirm engine code before ordering)

Fitment Notes

• Fits the third-generation Subaru FB-series boxer engine platform - the FB20 (1995cc) and FB25 (2498cc). These share the same crankpin journal dimensions, making a single bearing set applicable to both displacements.
• Standard (STD) crankshaft rod journal diameter - for use with stock or unworn crankpins at factory diameter only. Oversized variants are available for reground crankshafts.
• Note on WRX fitment: the 2015-2021 WRX uses the FA20DIT turbocharged engine in most markets, not the FB20B. Confirm your specific WRX engine code before ordering. Some JDM and non-US WRX variants use the FB20B.
• Does NOT fit the earlier EJ-series Subaru engines (EJ20, EJ25) - those require different bearings. The FB series replaced the EJ series starting 2010-2012 depending on model.
• Always measure crankshaft rod journal diameter with a micrometer before selecting bearing size. Confirm actual clearance with Plastigage or a dial bore gauge after assembly.
• Sold as a complete set of 8 bearing shells - sufficient for one full 4-cylinder engine build.
• UPC: 9315726450642

Features

• Tri-metal construction: copper-lead alloy lining bonded over a hardened steel backing, with a high-strength overlay plate - engineered for the demands of naturally aspirated and forced-induction Subaru FB-series boxer engines.
• Hardened steel backing on all rod bearings improves structural support of the bearing lining and maintains crush under high sustained loads in the horizontally-opposed engine configuration.
• High-strength overlay plate with reduced thickness provides improved fatigue resistance compared to OEM-spec bearings - a meaningful upgrade for any FB20/FB25 rebuild targeting improved reliability and longevity.
• Increased bearing crush and tighter wall tolerances ensure consistent, secure seating in the connecting rod housing bore, reducing the risk of bearing spin.
• Enlarged ID chamfers on bearing edges accommodate the larger fillet radii found on performance and aftermarket Subaru FB-series crankshafts.
• 3/4-groove design optimizes oil supply to the rod journal and maximizes load-carrying surface area across the bearing face.
• Elimination of flash plating on bearing backs improves heat transfer and maximizes grip between the bearing shell and the rod housing bore.
• Increased eccentricity compensates for bore distortion at high RPM and assists in the formation of a stable hydrodynamic oil film under load.

Specifications

• Part Number: 4B8325H-STD
• Product Line: ACL Race Series
• Application: Connecting Rod Bearings
• Engine Compatibility: Subaru FB20 (1995cc DOHC Boxer-4) and FB25 (2498cc DOHC Boxer-4)
• Crankshaft Size: Standard (STD - Unground)
• Shaft (Crankpin) Diameter: 47.976-48.000mm (1.8888-1.8898 in)
• Tunnel (Housing Bore): 51.000-51.024mm (2.0079-2.0088 in)
• Maximum Wall Thickness at Crown: 1.504mm (0.0592 in)
• Maximum Overall Length: 13.35mm (0.526 in)
• Bearing Material: Tri-Metal Copper-Lead Alloy / Hardened Steel Backing
• Quantity: Set of 8 Shells (complete engine set)
• UPC: 9315726450642

Included Components

• 8x Race Series Connecting Rod Bearing Shells - Standard Size

Product Description

The ACL Race Series 4B8325H-STD connecting rod bearing set is the standard-size performance replacement for Subaru's FB-series boxer engine family - the third-generation flat-4 platform covering the FB20 (2.0L) and FB25 (2.5L) DOHC engines introduced from 2010 onward. The FB-series succeeded the EJ engine family across Forester, Impreza, XV Crosstrek, Legacy, Outback, and WRX applications, bringing updated DOHC architecture with dual AVCS variable valve timing. The FB20 and FB25 share identical crankpin journal dimensions, making this a single versatile set for both displacements at standard crankshaft size.

Built on ACL's Race Series tri-metal platform, these bearings deliver superior fatigue resistance, bearing retention, and oil film stability over OEM Subaru shells - a reliable upgrade for any FB-series engine rebuild. Note the notably short bearing length (13.35mm) characteristic of the FB-series' compact boxer architecture. Verify your specific engine code before ordering, particularly for WRX applications where FA20DIT is common. Always confirm clearances at assembly. Sold as a complete set of 8 shells for one engine.