Forged Superlite Internal Caliper – Part No: 120-11331
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Forged Superlite Internal 4 ST
Prod #: 120-11331
Price: $420.91
Forged Superlite Internal 4 ST - Product Summary
Caliper No: 120-11331
Forged Superlite Internal 4 ST

Pistons
Piston Count 4
Piston Area (in²) 5.18
Piston Type Thermlock
Dust Boot No
Rotor Dimensions
Rotor Width (in) 1.25
Rotor Diameter(in) 13.06
Pad Dimensions
Pad Area (in²) 8.2
Pad Volume (in³) 4.9
Duty Rating & Material
Material Forged Aluminium
Weight(Lbs) 5.2
Colors & Finish
Color Anodize
Finish Type III Anodize

Mounting
Mount Center(in) 3.50
Mount Position
Mount Side Right Hand
Mount Type Lug
UPC Number
UPC 889545001389
Product Documents
Product Data Sheet

Click To Download
Installation Instructions


WARNING: Cancer and Reproductive Harm
www.P65Warnings.ca.gov
Applicable to Brake Pads Only

120-11331 - Product Description

Forged Superlite Internal 4 ST

FSLI4 and FSLI4/ST calipers provide the pad wear performance advantages of differential bore pistons with the option for ultimate heat protection using Thermlock® pistons in the ST models. Differential piston bores compensate for leading-edge mechanical loading and temperature variances across the pad face to reduce pad taper wear in sustained high temperature applications. Thermlock® pistons in the ST models block heat transfer from the pads and reduce temperatures in the caliper, fluid, and seals by up to 25% over standard stainless steel pistons. These are the go-to calipers for all types sustained hard braking on dirt and asphalt ovals and a wide range of off-road, rally and road course applications.

These new FSLI4 and FSLI4/ST models use the latest innovation to the Superlite family of calipers. They have been redesigned with internal fluid ports that eliminate the external fluid cross-over tubes, along with any potential problems that could arise from a damaged tube. The transfer tube has been replaced with two additional bleed screw assemblies which allow this group of right and left hand oriented differential piston bore calipers to be mounted in either a leading or trailing position.

The most noteworthy feature of all the FSLI caliper models is the exceptional strength and reduced weight of the forging. With assembled weights just at 4.4 pounds, the caliper body design in itself is a product of computer generated solid modeling and stress analysis technology. Each caliper features closed end bridges with a radial transition down to the main body and piston bore housings. The elimination of machined steps and sharp shoulders in this critical critical area provides a measurable increase in overall body strength and resistance to deflection under load. Every FSL body is stress-flow forged from a premium grade aluminum alloy billet. Stress-flow forging realigns the metal's internal grain structure to flow within the contour of the caliper body. This process eliminates the stresses and interruptions to the internal grain structure that occur when machining a straight block billet.



Product Specifications

Rotor Compatibility
Rotor Width (in) 1.25
Maximum Rotor Width (in) 1.38
Minimum Rotor Width (in) 1.19
Maximum Rotor Diameter(in) 13.06
Minimum Rotor Diameter(in) 11.75

Brake Pad Specifications
Brake Pad Type 1 7420
Brake Pad Type 2 N-A
Brake Pad Type 3 N-A
Total Pad Area (in²) 8.2
Total Pad Volume (in³) 4.9
Mount
Piston Specifications
Piston 1 Bore (in) 1.88
Piston 2 Bore (in) 1.75
Piston 3 Bore (in)
Total Piston Area (in²) 5.18

Mounting Specifications
Mount Type Lug
Mount Side Right Hand
Mount Center(in) 3.50
Mount Hole Size(in) 0.45
Mount Height(in) 2.85
Inlet Thread Size 1/8-27 NPT
Pad Dimensions & Part Numbers
Pad Dimensions for the Forged Superlite Internal 4 ST Pad Dimensions for the Forged Superlite Internal 4 ST Zoom Image
Axle Set P/N
Pad Type
Compound
Non-Bedded Pads - by Compounds
7420
BP-10
7420
BP-20
7420
BP-28
7420
BP-30
7420
BP-35
7420
BP-40
7420
BP-45
7420
BP-Q
7420
PolyMatrix H
Bedded-In Pads - by Compounds
7420
BP-40
7420
PolyMatrix B
7420
PolyMatrix H
Mount Dimensions & Part Numbers

Dimensions for the Forged Superlite Internal 4 ST Dimensions for the Forged Superlite Internal 4 ST Zoom Image

Additional Notes

FSLI calipers use high strength steel main bridge bolts in tension and a supplemental center bridge bolt to provide maximum resistance and strength against deflection and body separation under load. The center bridge support also provides positive pad retention with quick access when it’s time for service. Clamping force, structural deflection, and volume displacement tests have proven the superior strength and efficiency of the FSL. Simply stated, there is no better way to build a stronger or more efficient one or two-piece aluminum caliper body at equal or lower weight.

FSLI calipers feature all of Wilwood’s latest refinements and proven performance features including replaceable SRS stainless steel bridge plates. SRS plates extend caliper life by preventing wear at the bridge abutments otherwise caused by pad edge gouging. Spring tension in the SRS plates also eliminates pad rattle and helps to dampen the vibration harmonics that can contribute to squeal under braking. Other standard Wilwood features include high-temperature, square faced o-ring seals for positive sealing, controlled piston retraction, and long service life in high heat conditions. Machined stainless steel pistons are used in the standard models to resist corrosion, retard heat transfer, and eliminate backside deflection under pressure. Two-piece bleed screw assemblies provide long, reliable service life and are easily replaced if necessary.


Parts & Accessories

O-Ring Kit 130-2427
Replacement Dust Boot N-A
Replacement Piston 1 200-7550
Replacement Piston 2 200-7551
Replacement Piston 3 N-A
Replacement Piston 4 N-A
Cross-Over O-Ring Kit 130-10540
Bridge Bolt Kit 230-7541
Wear Plate L/H 300-5923
Wear Plate R/H 300-5922
Pad Retainer N-A
Bleed Screw Kit 220-0627
Self Bleeder Tube N-A
Cross-Over Tube N-A
Recommended Caliper Adapters & Bolt Kits
150-12245K
150-12245K
PAD,7420-40,SL6,.80 THK,W/BRIDGE,AXLE SET
PAD,7420-40,SL6,.80 THK,W/BRIDGE,AXLE SET
150-12245K
150-12245K
PAD,7420-40,SL6,.80 THK,W/BRIDGE,AXLE SET
PAD,7420-40,SL6,.80 THK,W/BRIDGE,AXLE SET
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Version: 3.05 June 23, 2023