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ACT Streetlite Steel Flywheel 2004-2021 STI - 600235 - Subimods.com

ACT Streetlite Steel Flywheel 2004-2021 STI

$476.00
$588.00
$588.00 - $588.00
$588.00
$476.00 - $476.00
$476.00
-19% -19%
32 In Stock, Usually Ships within 1-2 Business Days
SKU 600235
by ACT
Lease to own Pay as low as $/week

DETAILS

ACT Streetlite Steel Flywheel 2004-2021 STI | Performance Enhancement | Drivetrain Upgrade

Overview

The ACT Streetlite Steel Flywheel is a high-quality upgrade designed specifically for Subaru WRX STI models from 2004 to 2021. This performance-oriented flywheel reduces rotational mass, resulting in quicker throttle response, more precise engine engagement, and smoother acceleration—ideal for enthusiasts who want to optimize their daily driver or spirited street car. Crafted from hot-forged chrome-moly steel, it offers superior strength and heat tolerance compared to OEM cast flywheels, ensuring durability under demanding driving conditions.

Built with a focus on engineering excellence, the ACT Streetlite Flywheel features precision CNC machining and dynamic computer balancing. This meticulous manufacturing process guarantees high RPM stability and long-lasting reliability, making it a dependable choice for Subaru owners who demand performance without sacrificing safety or daily drivability. Its design lowers inertia while maintaining rigidity, providing a noticeable improvement in engine response and overall drivetrain feel. Whether you're tuning for more power or simply upgrading your OEM component, this flywheel enhances the driving experience for Subaru enthusiasts who value quality and performance.

By reducing the rotational mass, this flywheel allows your STI to rev more freely, translating into quicker acceleration and more responsive throttle control. Its compatibility with stock and aftermarket clutches makes it a versatile upgrade for those looking to improve engagement and durability. Perfect for street-driven Subarus, the ACT Streetlite Steel Flywheel offers a reliable, high-performance solution that elevates your vehicle’s drivetrain dynamics without compromising everyday usability.

Features & Specifications

This ACT Streetlite Steel Flywheel is engineered for Subaru WRX STI models and features a hot-forged chrome-moly steel construction, delivering increased strength and heat resistance for demanding street driving and tuning applications.

  • Brand: ACT
  • Product: Streetlite Steel Flywheel 2004-2021 STI
  • Part Number: (Refer to product details for specific part number)
  • Fitment: Subaru WRX STI (2004-2021)
  • Material: Hot-forged chrome-moly steel
  • Finish: Natural steel with protective coating
  • Construction: CNC machined and computer-balanced
  • Origin: Made in the USA

Key Benefits

  • Enhanced Throttle Response: Reduces rotational mass for quicker engine revving and more immediate power delivery, improving street driving feel.
  • Durability & Heat Tolerance: Constructed from high-strength chrome-moly steel, offering superior heat resistance and longevity under spirited driving conditions.
  • Reliable Fitment: Precisely CNC-machined with high RPM stability, ensuring a seamless upgrade for your STI without compatibility issues.
  • Improved Drivetrain Engagement: Lower inertia enhances clutch engagement and overall driving feel, making shifts smoother and more predictable.
  • OEM Replacement Quality: Designed to match or exceed OEM standards, providing peace of mind for daily drivers and performance enthusiasts alike.

What's Included

  • 1× ACT Streetlite Steel Flywheel
  • Installation hardware (if included in kit)
  • Installation instructions

Installation & Compatibility

Installing the ACT Streetlite Steel Flywheel is a straightforward process for experienced DIY enthusiasts with basic mechanical skills. However, due to the importance of proper clutch engagement and drivetrain balance, professional installation is recommended. The flywheel is a direct bolt-on replacement for OEM units on Subaru WRX STI models from 2004 to 2021, ensuring a perfect fitment and reliable performance. Tuning your ECU or clutch setup may be beneficial to maximize the benefits of reduced rotational mass and to ensure optimal drivability. Always verify compatibility with your specific vehicle year and trim before installation.

Which Clutch Kit is Right for Me: HD or XT? 

The choice between an HD (Heavy Duty) and XT (Xtreme Duty) clutch depends on your power level and driving style. The HD clutch is ideal for daily drivers and street-focused builds, offering a 20-50% increase in clamping force while maintaining smooth engagement and drivability. It is best suited for vehicles with mild to moderate performance upgrades that see a mix of city driving and occasional track use. On the other hand, the XT clutch is designed for high-performance applications, providing up to a 150% increase in clamping force with a more aggressive engagement. This makes it the preferred choice for heavily modified vehicles, track-focused builds, and those requiring maximum durability and grip. If you prioritize comfort and versatility, the HD clutch is the better option, while the XT clutch is the right choice for extreme performance and aggressive driving.

What’s the Difference Between a Full-Face Disc and a Pucked Clutch? 

Choosing between a full-face organic disc and a pucked cerametallic disc depends on your driving habits and performance needs. A full-face organic disc is best suited for daily driving and mild performance upgrades, offering smooth engagement, longevity, and quiet operation, making it ideal for street-focused vehicles with basic modifications. In contrast, a pucked cerametallic disc is designed for high-performance applications, featuring quick engagement, superior heat resistance, and higher torque capacity. This makes it the go-to option for racing, drifting, and vehicles with significant power upgrades. If you prioritize comfort and seamless engagement for daily use, the full-face organic disc is the right choice. However, if you need rapid engagement and superior performance under extreme conditions, a pucked clutch is the better option.

When Should I Choose a Single Disc Over a Twin Disc Clutch? 

The decision between a single disc and twin disc clutch depends on your vehicle’s power level and intended use. A single disc clutch is best for daily drivers and vehicles with moderate performance upgrades, handling up to 400-600 FT-LB of torque. It provides smooth engagement, an OEM-like pedal feel, and cost-effective performance, making it a great choice for street use with bolt-on modifications like intakes, exhausts, and tuning. Conversely, a twin disc clutch is ideal for high-performance builds exceeding 600 FT-LB of torque, offering superior heat dissipation, higher torque capacity, and faster shifts. This makes it the preferred option for competitive motorsports, aggressive driving, and vehicles requiring extreme torque handling. If you want a balance of affordability and daily drivability, a single disc clutch is the way to go, whereas a twin disc clutch is essential for high-power builds and track-ready performance.

How Do I Decide Between a Prolite and Streetlite Flywheel? 

The choice between a Prolite and Streetlite flywheel depends on your driving style and vehicle modifications. The Streetlite flywheel is designed for daily drivers and street builds, featuring slightly more mass to improve drivability, smooth engagement, and better heat dissipation. This makes it a great option for vehicles that see a mix of city driving and occasional track days. In contrast, the Prolite flywheel is engineered for racing and aggressive performance, offering a lightweight design that reduces mass for quicker revs, sharper throttle response, and faster shifts. This makes it ideal for high-horsepower or lightweight builds focused on track performance. If you need a flywheel that balances comfort and performance for versatile driving, the Streetlite flywheel is the better choice. However, if you prioritize ultimate responsiveness and fast acceleration, the Prolite flywheel is the superior option.

Brand Logo
ACT Performance Flywheels

ACT Performance Flywheels

ACT Performance Flywheels are built for strength, durability, and precision using a one-piece chrome-moly forging, which surpasses billet steel, aluminum, and cast iron in performance. Featuring an integral ring gear that is induction-hardened for maximum gear life, these flywheels are engineered for optimal mass distribution, ensuring excellent strength, heat dissipation, and reduced inertia. CAD-designed, CNC-machined, and computer-balanced, they deliver smooth operation across all RPM ranges. Heat-treated and tempered, ACT Performance Flywheels are crafted for reliability and precision, making them an ideal choice for high-performance applications.

DESIGN AND ENGINEERING

DESIGN AND ENGINEERING

Advanced Clutch Technology designs, engineers and develops products by leveraging decades of track and performance street experience. Advanced CAD, FEA simulation and CAM tools help ensure highly optimized performance, reliability and repeatability. These key advantages are produced by combining the best engineering and design methodologies with the latest in materials and manufacturing techniques.

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