Wilwood 120-16683-Y Forged Narrow Superlite Radial Mount Brake Caliper - 4R

The Wilwood Forged Narrow Superlite 4R (FNSL4R) caliper represents the latest evolution in high-performance brake caliper technology. Designed for radial mounting, this caliper simplifies installation and offers two planes of adjustment for precise alignment over the brake disc, making it ideal for a wide range of performance and racing applications.

Advanced Forged Construction:

At the heart of the FNSL4R's exceptional performance is its stress-flow forged aluminum body. Each caliper is forged from premium-grade aluminum alloy billets using a specialized process that re-aligns the metal's internal grain structure to flow within the contour of the caliper body. This eliminates the internal stresses and grain interruptions that occur with traditional billet machining, resulting in superior strength and durability. Despite its robust construction, the caliper weighs just 4.9 pounds, achieved through computer-generated solid modeling and FEA stress analysis.

Key Features:

• Radial mounting design with dual-plane adjustment capability
• Stress-flow forged aluminum body for maximum strength-to-weight ratio
• One-piece stainless steel pistons with slow heat transfer properties and superior corrosion resistance
• Available in multiple piston bore sizes for front or rear brake applications
• Compatible with Wilwood Thermlock pistons for enhanced thermal barrier performance
• SRS (Stainless Rotor Saver) bridge plates eliminate pad gouging and extend service life
• Spring-loaded SRS plates eliminate pad rattle and reduce harmonic vibrations that cause squeal
• Two-piece bleed screws on each end with internal fluid crossovers for protection against debris damage
• High-temperature square-faced bore seals provide maximum sealing area and controlled piston retraction

Thermal Management:

The FNSL4R is engineered to manage extreme heat conditions. The stainless steel pistons provide natural thermal resistance, while optional Thermlock pistons create a multi-part thermal barrier that further reduces heat transfer from the pads to the caliper body, seals, and brake fluid. This translates to cooler operating temperatures, extended component life, and reduced risk of heat-induced brake fade during demanding driving conditions.

Compatible with the complete range of Wilwood pad compounds, allowing you to precisely match brake response and heat capacity to your specific competition or performance driving requirements.