Description

The CUSCO LSD Spec-F Series is a specialized, track-focused limited slip differential system engineered for the GR Yaris, offering refined torque sensitivity and tailored lock-up characteristics for advanced competition and high-performance driving. As an evolution of the standard CUSCO LSD, the Spec-F variants feature modified initial torque ranges and optimized internal components to provide a more progressive and controllable lock-up feel, ideal for drivers seeking maximum chassis adjustability and precision at the limit.

Product Highlights

🏁 Competition-Optimized Spec-F Tuning
The Spec-F designation indicates a refined calibration for competition use, featuring a lower and more sensitive initial torque range (2-4 kgf·m) compared to the standard version. This allows for smoother, more progressive engagement and finer modulation of lock-up by the driver.

🔧 Customizable Performance Profiles
Choose from two distinct lock-up characteristics to perfectly match your driving style and vehicle setup:

• 1-Way LSD Spec-F: Provides lock-up exclusively during acceleration (on-throttle). Engineered for drivers who want maximum, controllable traction on corner exit with minimal effect on corner entry.

  • Available Initial Torque Settings: 3.5° or 4.5° (with Spec-F’s 2-4 kgf·m sensitivity)

  • Product Code: LSD-1C7-FT

• 1.5-Way LSD Spec-F: Provides strong lock-up during acceleration and moderate lock-up during deceleration. This dual-phase action helps stabilize the vehicle during trail-braking and corner entry while delivering aggressive traction on exit.

  • Available Initial Torque Settings: 3.5°/20° or 4.5°/20° (with Spec-F’s 2-4 kgf·m sensitivity)

  • Product Code: LSD-1C7-VT15

⚡ Enhanced Drivability & Chassis Control

• Progressive Engagement: The Spec-F’s lower initial torque allows for smoother application of locking force, giving experienced drivers more nuanced control over power delivery and vehicle rotation.

• Optimized for Slick Tires: The calibration is particularly effective with high-grip slick or semi-slick tires, where subtle differential behavior has a significant impact on lap times and balance.

• Standard RS Spring Set: Includes 6 high-rate RS springs as standard for consistent and durable clutch pack operation under extreme conditions.

Technical Specifications & Product Codes

All Spec-F Models Include:

• Initial Torque Range: 2-4 kgf·m (Spec-F Specific)

• Springs: RS Spring Standard (6 pieces)

1-Way LSD Spec-F:

• Lock-Up Function: Acceleration (On-Throttle) Only

• Available Settings: 3.5° or 4.5°

• Product Code: LSD-1C7-FT

• JAN Code: 4996338108814

1.5-Way LSD Spec-F:

• Lock-Up Function: Strong on Acceleration, Moderate on Deceleration

• Available Settings: 3.5°/20° or 4.5°/20°

• Product Code: LSD-1C7-VT15

• JAN Code: 4996338108821

* Toyota GR Yaris RS grade model 5BA-MXPA12 (FF) is unconfirmed

Selection & Professional Notes

🎯 Ideal Application:

• Spec-F is designed for experienced drivers and dedicated competition vehicles (Time Attack, Circuit Racing, Drift).

• The nuanced engagement is best utilized by drivers who can feel and exploit subtle changes in differential behavior.

⚠️ Mandatory Professional Installation & Setup
This is a complex mechanical assembly requiring differential disassembly, precise shimming, and specialized knowledge. Installation must be performed by a certified differential or racing specialist. Proper break-in procedures with CUSCO LSD-specific fluid are required.

🔩 Not a “Street” Differential
The Spec-F’s lower initial torque and aggressive tuning are optimized for competition. For primarily street-driven vehicles or those seeking a more forgiving engagement, the standard CUSCO LSD may be a more suitable choice.