Introduction
The Cusco Street ZERO A Coilovers are a top-of-the-line street series model designed to enhance your vehicle's performance and ride comfort. They feature full-length adjustable height adjustment and 40 levels of attenuation force, allowing for precise tuning to suit various driving conditions and preferences. This manual provides essential information for the proper installation, operation, and maintenance of your coilovers.
Key features include:
- Full-length adjustable car height adjustment (front and full tap type).
- Front: Camber adjustable pillow upper mount; Rear: Reinforced rubber upper mount.
- Freely adjustable attenuation force with 40 levels.
- Equipped with CPRV (Pressure Regulating Valve) for consistent attenuation at low speeds.
- Designed specifically for vehicle models to ensure sufficient bump stroke even when lowered.
- Adjustment screws with nickel-chrome plating for rust protection.
Product Overview
This image displays the four individual coilover units, each consisting of a spring, damper, and upper mount, designed for vehicle suspension. The units are predominantly blue with black springs and orange adjustment rings.
This image features the "Street ZERO A" logo prominently at the top, followed by a white rally-style Toyota GR Yaris adorned with Cusco racing livery. This illustrates the performance application of Cusco products.
Setup and Installation
Installation of coilovers requires specialized tools and automotive knowledge. It is highly recommended that installation be performed by a qualified professional. Improper installation can lead to vehicle damage, poor performance, or safety hazards.
Pre-Installation Checks:
- Verify that the coilover model (6C1-61N-CN) is compatible with your vehicle (Toyota GR86 ZN8 or Subaru BRZ ZD8).
- Inspect all components for any shipping damage or missing parts. Refer to the "What's in the Box" section for expected contents.
- Ensure you have all necessary tools, including a torque wrench, spring compressor (if required for disassembly of old suspension), and appropriate sockets/wrenches.
General Installation Steps (Consult a professional service manual for detailed vehicle-specific instructions):
- Safely lift the vehicle and secure it on jack stands.
- Remove the wheels.
- Carefully remove the OEM suspension components.
- Install the new Cusco coilovers, ensuring proper orientation and torque specifications for all bolts and nuts.
- Adjust the initial ride height as desired (refer to the "Operating" section for adjustment details).
- Reinstall wheels and lower the vehicle.
- Perform a wheel alignment after installation to ensure proper handling and tire wear.
Operating and Adjustment
The Cusco Street ZERO A Coilovers offer extensive adjustability for both ride height and damping force, allowing you to fine-tune your vehicle's suspension to your driving style and road conditions.
Ride Height Adjustment:
These coilovers feature full-length adjustable car height adjustment. This means the spring preload and damper stroke remain consistent regardless of ride height, preserving ride quality. To adjust ride height:
- Loosen the lower lock ring on the coilover body.
- Rotate the main body of the coilover to raise or lower the vehicle. Clockwise rotation typically lowers the vehicle, while counter-clockwise raises it.
- Once the desired height is achieved, tighten the lower lock ring securely.
- Recommended Car Height Adjustment Width: Front: 1.0 - 0.0 inches (25 - 0 mm); Rear: 1.0 - 0.2 inches (25 - 5 mm).
This image provides a cross-section view of the shock absorber, highlighting the nickel-chrome plating on the adjustment screw for rust prevention. It also includes a graph demonstrating how damping force changes across 40 levels, from soft to hard, and how it relates to piston speed.
Damping Force Adjustment (40 Levels):
The coilovers feature 40 levels of damping force adjustment, allowing precise control over ride comfort and handling. The adjustment dial is typically located at the top of the shock absorber shaft (for strut type) or at the bottom (for some multi-link applications).
- To adjust, locate the knurled dial on the coilover. No special tools are required for adjustment.
- Rotate the dial clockwise for a firmer ride (increased damping force) and counter-clockwise for a softer ride (decreased damping force).
- Ensure that adjustments are made evenly on both sides of the vehicle (front and rear) to maintain balanced handling.
- The CPRV (Pressure Regulating Valve) ensures consistent attenuation even at low speeds, providing optimal ride comfort and high maneuverability across all speed ranges.
This image provides a detailed look at the internal workings of the coilover's damping system, including the piston rod, needle valve, and the CPRV (Pressure Regulating Valve), which helps maintain consistent damping force across various speeds.
This image illustrates the function of the CPRV (Pressure Regulating Valve) in maintaining optimal damping force. It also highlights compatibility with the optional e-Con2 damping controller, which allows for in-cabin electronic adjustment of damping force.
For even more convenient damping adjustment, the coilovers are compatible with the optional Cusco e-Con2 electronic damping controller (sold separately). This allows for in-cabin adjustment of the 40 damping levels.
Maintenance
Regular maintenance is crucial for the longevity and optimal performance of your Cusco Street ZERO A Coilovers.
- Regular Cleaning: Keep the coilover bodies, springs, and adjustment threads clean from dirt, salt, and debris. Use mild soap and water, then rinse thoroughly.
- Inspect for Damage: Periodically check for any signs of leaks from the damper seals, bent shafts, damaged springs, or loose components.
- Check Torque: After initial installation and periodically thereafter (e.g., every 5,000 miles or after track use), re-check the torque of all mounting bolts and nuts to ensure they are secure.
- Lubrication: While the adjustment screws are nickel-chrome plated for rust protection, applying a thin layer of silicone grease to the threads can further aid in smooth height adjustments and prevent seizing.
- Alignment: Always perform a wheel alignment after any significant ride height adjustments or suspension component replacement.
Troubleshooting
If you experience issues with your coilovers, consider the following common troubleshooting steps:
| Symptom | Possible Cause | Solution |
|---|---|---|
| Excessive Noise (clunking/squeaking) | Loose mounting bolts, worn bushings, spring coil bind, debris in upper mount. | Check and re-torque all mounting hardware. Inspect bushings for wear. Clean spring seats and upper mounts. |
| Uneven Ride Height | Incorrect height adjustment, uneven spring preload, damaged component. | Re-measure and adjust ride height on all four corners. Ensure spring preload is consistent. Inspect for bent components. |
| Poor Ride Quality (too harsh/too soft) | Incorrect damping force setting, incorrect spring rates, damaged damper. | Adjust damping force (refer to "Operating" section). Verify correct spring rates are installed. If issues persist, professional inspection of dampers may be needed. |
| Oil Leaks from Damper | Damaged seal, internal damper failure. | This indicates a serious issue. Contact Cusco support or a qualified suspension specialist for repair or replacement. |
If troubleshooting steps do not resolve the issue, please contact Cusco customer support or a certified automotive technician.
Specifications
| Feature | Detail |
|---|---|
| Model Name | Street ZERO A |
| Item Model Number | 6C161NCN |
| Manufacturer Part Number | 6C1-61N-CN |
| Fitment | Toyota GR86 Model: ZN8 (October 2021 onwards) Subaru BRZ Model: ZD8 (August 2021 onwards) |
| Height Adjustment Type | Full length adjustable (front and full tap type) |
| Upper Mount (Front) | Camber adjustable pillow upper mount |
| Upper Mount (Rear) | Reinforced rubber upper mount |
| Damping Force Adjustment | 40 levels, freely adjustable |
| Standard Front Spring Rate | 7 kgf/mm (065-150-07R) |
| Standard Rear Spring Rate | 7 kgf/mm (065-180-07) |
| Recommended Front Height Adjustment | 1.0 - 0.0 inches (25 - 0 mm) |
| Recommended Rear Height Adjustment | 1.0 - 0.2 inches (25 - 5 mm) |
| Item Weight | 55.4 pounds |
| Package Dimensions | 27.56 x 19.69 x 15.75 inches |
Warranty and Support
Cusco products are manufactured to high standards. While specific warranty details are not provided in this manual, generally, Cusco offers a 1-year or 10,000km warranty on its products, requiring user registration.
For technical support, warranty claims, or further assistance, please contact Cusco customer service or your authorized dealer. Always provide your product model number (6C1-61N-CN) and proof of purchase when seeking support.
What's in the Box: According to the kit configuration.