Wilwood 120-11137 Forged Superlite Internal Brake Caliper - FSLI4 4-Piston

The Wilwood FSLI4 (Forged Superlite Internal) caliper represents the latest evolution in high-performance brake caliper design, combining differential bore piston technology with innovative internal fluid porting. Engineered for sustained hard braking in oval track, road racing, rally, and off-road applications, this caliper delivers exceptional stopping power while weighing just 4.4 pounds.

Key Features:

• Stress-flow forged aluminum body from premium grade billet for superior strength and reduced weight
• Internal fluid ports eliminate external crossover tubes and potential failure points
• Differential bore pistons provide optimized pad wear characteristics and braking performance
• Reversible design mounts in leading or trailing positions with dual bleed screw assemblies
• Closed-end bridge design with radial transitions increases body strength and deflection resistance
• High-strength steel main bridge bolts with supplemental center bolt prevent body separation under load
• Replaceable SRS stainless steel bridge plates prevent pad edge gouging and eliminate pad rattle
• Machined stainless steel pistons resist corrosion and minimize heat transfer
• High-temperature square-faced O-ring seals provide controlled piston retraction and positive sealing
• Two-piece bleed screw assemblies for reliable, long-term serviceability

Computer-generated solid modeling and stress analysis optimized every aspect of the FSLI4 body design. The stress-flow forging process realigns the metal's internal grain structure to follow the caliper body contours, eliminating machining-induced stress concentrations found in conventional billet construction. The result is measurably superior clamping force efficiency, reduced deflection under load, and unmatched strength-to-weight ratio in a four-piston aluminum caliper.