Cusco Lightweight Aluminum Pulley Set

2011–2025 Subaru WRX / STI GDB / GRB / GVB / VAB 2.0L EJ20 / EJ25

Part #: 6A1 733 A

Overview

The Cusco Lightweight Aluminum Pulley Set is designed to enhance the performance and efficiency of your Subaru WRX or STI equipped with EJ20 or EJ25 engines. Crafted from high-quality aluminum, this pulley set reduces rotational mass, leading to less stress on your engine components and improved acceleration response. Ideal for enthusiasts seeking to optimize their vehicle's performance, this set offers a combination of durability, lightweight construction, and a striking blue finish that complements your engine bay.

By replacing the stock pulleys with these lightweight alternatives, you'll experience a noticeable reduction in parasitic drag, which can contribute to better throttle response and potentially increased horsepower and torque. The installation process is straightforward, typically taking around two hours, making it accessible for DIY enthusiasts and professional mechanics alike.

Key Features

The Cusco Lightweight Aluminum Pulley Set incorporates several advanced features designed to maximize performance and reliability:

• Constructed from high-grade aluminum for a lightweight yet durable solution that withstands engine heat and stress.
• Significantly reduces the rotational mass of the crank and alternator pulleys—crank pulley weighs only 790 grams (1.74 lbs) compared to the stock 2.3 kg (5.07 lbs), and alternator pulley weighs just 76 grams (0.16 lbs) versus 300 grams (0.66 lbs).
• Precision-machined for perfect fitment and smooth operation, ensuring no adverse effects on belt tension or alignment.
• Finished in a vibrant blue color, adding a sporty aesthetic to your engine bay.
• Designed specifically for Subaru EJ20 and EJ25 engines, ensuring compatibility and optimal performance gains.
• Engineered to help support better acceleration, throttle response, and overall engine efficiency by reducing rotating inertia.
• Manufactured with quality craftsmanship to ensure long-lasting performance and resistance to engine heat and vibration.

Construction & Design

The Cusco pulley set features a one-piece aluminum construction that combines strength with lightweight properties. Each pulley is CNC-machined to precise specifications, guaranteeing a perfect fit and smooth operation. The use of high-grade aluminum not only reduces weight but also provides excellent heat dissipation, helping to maintain optimal engine temperatures during spirited driving or track use. The vibrant blue anodized finish adds a sporty look while providing corrosion resistance, ensuring the pulleys maintain their appearance over time.

Performance & Sound

While specific horsepower or torque gains are not provided, the reduction in rotational mass directly contributes to improved engine responsiveness and acceleration. The lightweight pulleys help decrease parasitic losses, allowing your engine to operate more efficiently. Additionally, the aluminum construction can subtly influence engine sound, often resulting in a slightly more aggressive and sporty tone during acceleration, enhancing the driving experience.

Installation & Fitment

The Cusco Lightweight Aluminum Pulley Set is designed as a direct bolt-on replacement for the stock pulleys on your Subaru WRX or STI with EJ20 or EJ25 engines. The installation process typically takes about two hours and requires basic hand tools. No special modifications, cutting, or tuning are necessary, making it a convenient upgrade for both DIY enthusiasts and professional installers. Proper belt tension should be checked after installation to ensure optimal performance and longevity.

• Easy bolt-on installation with standard hand tools
• No cutting, drilling, or tuning required
• Compatible with stock belts and accessories

What's Included

• Complete set of lightweight aluminum pulleys for crank and alternator
• All necessary mounting hardware and fasteners
• Installation instructions

Ideal For

• Performance enthusiasts looking to improve engine responsiveness
• Subaru WRX and STI owners seeking a lightweight upgrade
• Drivers aiming to reduce engine stress and enhance acceleration
• DIYers and professional mechanics performing bolt-on modifications

Emissions Note

This product is designed for off-road or racing use only and may not be legal for street use in all regions. Please check local regulations before installation.