GFB 2221 Lightweight Alternator Pulley 6061-T6 Aluminum Scion FR-S Subaru BRZ

Vehicle Fitment

• 2013-2016 Scion FR-S (2.0L FA20 H4)
• 2013-2020 Subaru BRZ (2.0L FA20 H4)
• 2017-2020 Toyota 86 (2.0L FA20 H4)

Fitment Notes

• Alternator pulley replacement only - this is a single pulley, not a kit; for the matching lightweight water pump pulley, see GFB 2223; for both pulleys together, see GFB bundle 2221-2223
• OEM diameter - this is a same-size lightweight pulley, not an underdrive pulley; it reduces rotating mass without changing pulley ratio or accessory drive speed
• No supporting modifications or ECU tuning required - direct bolt-on replacement
• Not compatible with 2021+ Subaru BRZ or 2021+ Toyota GR86 (FA24 engine)
• Backed by GFB's lifetime warranty
• UPC: 9328022002712

Features

• 77% weight reduction over the factory alternator pulley - GFB pulley weighs 0.18 lb vs. the factory pulley at 0.44 lb, a savings of 0.26 lb
• 83% reduction in rotating inertia - inertia (not just mass) is the key metric for how much effort the engine expends spinning the pulley on every revolution; reducing inertia by 83% produces a significantly more noticeable improvement than the raw weight saving alone suggests
• The effect is similar to a lighter flywheel - the engine feels more eager to rev, throttle response sharpens, and there's a stronger sense of acceleration throughout the RPM range
• CNC-machined from a single billet of aircraft-grade 6061-T6 aluminum - precision tolerances ensure perfect fit and long-term reliability with no slop or vibration
• Black anodized finish - superior wear resistance and a stealthy underhood appearance
• Manufactured in Australia in accordance with ISO 9001 quality standards

Specifications

• Application: Alternator Pulley
• Pulley Diameter: OEM diameter (same-size replacement, not underdrive)
• Material: 6061-T6 Aluminum (aircraft-grade billet)
• Finish: Black Anodized
• GFB Pulley Weight: 0.18 lb (0.082 kg)
• Factory Pulley Weight: 0.44 lb (0.200 kg)
• Weight Savings: 0.26 lb (59%)
• Rotating Inertia Reduction: 83%
• Compatible Engine: FA20 (2.0L Horizontally-Opposed Four-Cylinder)
• Country of Manufacture: Australia
• Quality Standard: ISO 9001
• Warranty: Lifetime
• UPC: 9328022002712

Included Components

• 1x GFB Lightweight Alternator Pulley (black anodized 6061-T6 aluminum)

Product Description

The GFB 2221 is a lightweight alternator pulley for the FA20-powered Scion FR-S (2013-2016), Subaru BRZ (2013-2020), and Toyota 86 (2017-2020). CNC-machined from a single billet of aircraft-grade 6061-T6 aluminum and black anodized for wear resistance, it replaces the heavy factory steel alternator pulley with a component that weighs 0.18 lb versus the factory's 0.44 lb - a 59% weight reduction.

Weight alone, however, undersells the upgrade: because the pulley's rotating inertia is reduced by 83%, the engine must do significantly less work to spin it on every revolution, producing an effect similar to a lighter flywheel. The car feels more willing to rev, throttle response sharpens, and there's a stronger sense of acceleration at all RPM levels. Unlike underdrive pulley kits, the 2221 is an OEM-diameter replacement that does not change the alternator's drive speed - making it suitable for daily-driven vehicles without concerns about charging system output at idle.

No tune or supporting modifications are required - this is a direct bolt-on swap. For maximum benefit, pair with the GFB lightweight water pump pulley (GFB 2223) or purchase both together as the GFB 2221-2223 two-piece pulley kit. GFB backs this pulley with a lifetime warranty for the original owner.