High Output Alternator for Subaru Legacy (2015-2017) 2.5L

Direct-Fit 250A High Output Alternator for 2015-2017 Subaru Legacy (BN)

What it Does: The 250 amp high output alternator replaces the factory charging unit on the 2015-2017 Subaru Legacy to supply increased amperage, preventing critical voltage drop under heavy electrical loads.

The Stock Subaru Legacy Electrical Limitation

The factory charging system on the BN chassis Subaru Legacy is engineered strictly for base electrical demands. When aftermarket sound systems, high-draw lighting, or performance electronics are installed, the stock unit suffers from thermal saturation and excessive voltage drop at idle speeds. Sustained current demand overtaxes OEM diodes and stator coils, resulting in system voltage sagging below 13.0V, premature battery degradation, dimming headlights, and erratic electronic control module (ECM) operation.

The Engineering Solution

Engineered for high-demand duty cycles, this 250-amp alternator utilizes heavy-gauge copper stator windings, a precision dynamic-balanced rotor, and high-temp sealed bearings to minimize parasitic drag and dissipate heat effectively. Featuring an internal solid-state voltage regulator, it stabilizes system charging between 13.5V and 14.5V across the entire RPM band. The housing retains factory mounting ears, pulley geometry, and plug polarity, facilitating direct bolt-in installation onto the FB25 engine block with zero wiring harness splicing.

What's Included

• 1x 250 Amp High Output Alternator (Part # 44010)

Technical Specifications

Compatibility

• 2015 Subaru Legacy 2.5L (Base, Premium, Limited)
• 2016 Subaru Legacy 2.5L (Base, Premium, Sport, Limited)
• 2017 Subaru Legacy 2.5L (Base, Premium, Sport, Limited)

Frequently Asked Questions & Fitment Warnings

Does this fit the BN Legacy?

Yes, this is a direct fit for the 2015-2017 Subaru Legacy equipped with the FB25 2.5L engine. Does not fit 3.6L H6 models.

Do I need to upgrade my vehicle wiring when installing this unit?

While this alternator utilizes the factory connector and charge post, upgrading the main battery charge wire and chassis ground straps (Big 3 upgrade) is strongly recommended to handle 250-amp flow without thermal resistance.

The Subaru Performance Standard

Maintain consistent electrical stability and uninterrupted sensor signals on your boxer powertrain, ensuring mission-critical electronics run efficiently even under heavy demand.