Audi S3 8P / 8V – BTCC Big Brake Kit – Endurance AP Racing CP9668 25mm Pad Complete Upgrade | XC3 Engineering

XC3 Engineering 25mm Endurance BTCC Big Brake Kit – Audi S3 8P / 8V

Unlock serious braking performance from your Audi S3 8P or 8V with the XC3 Engineering BTCC Big Brake Kit, built around AP Racing CP9668 Pro 5000 R six-piston endurance calipers.

This complete front brake upgrade combines 368 × 36 mm ex-BTCC floating rotors, full-depth 25mm Pagid RSL29 endurance brake pads, XC3 precision-engineered rotor bells and caliper brackets, braided brake lines and AP Racing floating hardware.

Designed for demanding fast-road, trackday and endurance-style use, the kit offers increased thermal capacity, longer pad life and more consistent braking performance under repeated high-temperature conditions.

Why Choose the CP9668 Endurance Kit?

The AP Racing CP9668 is designed around a deeper 25mm brake pad, giving it a clear advantage for drivers who regularly subject the car to longer or more demanding braking sessions.

Potential benefits include:

• Increased braking consistency
• Greater thermal capacity
• Longer pad life
• Improved endurance capability
• Better resistance to brake fade
• Stronger repeatability under repeated heavy braking
• Motorsport-derived component design
• Suitable for trackday and high-performance road use

AP Racing CP9668 Pro 5000 R Calipers

At the heart of the system are AP Racing CP9668 Pro 5000 R six-piston endurance calipers.

These are designed for serious performance use and feature a deeper 25mm pad format compared with the 18mm format used in the CP9660.

The increased friction material volume can help improve:

• Consumable life
• Heat management
• Long-session consistency
• Suitability for endurance-focused use

Choice of Caliper Finish

The CP9668 calipers are available in a choice of:

• Nickel Plated
• Anodised Grey

The nickel-plated option provides a premium corrosion-resistant finish, while the anodised grey option gives a more motorsport-focused appearance.

25mm Pagid Racing RSL29 Endurance Pads

The kit includes brand new Pagid Racing RSL29 25mm endurance brake pads.

RSL29 is a proven endurance-focused compound known for progressive response, good modulation and strong consistency over longer sessions.

Key characteristics include:

• Progressive pedal feel
• Good modulation
• Strong endurance performance
• Long pad life
• Good disc life
• Predictable response

This makes RSL29 especially well suited to drivers who want a confidence-inspiring pad for repeated track use without an excessively aggressive initial bite.

368 × 36 mm Ex-BTCC Floating Rotors

The kit uses 368 × 36 mm ex-BTCC floating brake rotors.

These motorsport-derived discs provide substantial thermal capacity and are designed to cope with repeated high-energy braking.

The larger rotor size helps manage heat, while the floating construction allows controlled expansion as temperatures increase.

Floating Rotor Design

As the brake rotor heats up, the floating bobbin system allows the disc to expand more freely relative to the bell.

This can help support:

• More consistent braking
• Improved thermal behaviour
• Reduced thermal stress
• Better repeatability under heavy use

XC3 Anodised Rotor Bells

XC3 Engineering rotor bells are included as part of the kit.

These provide the interface between the Audi hub and the BTCC rotor, helping ensure:

• Accurate rotor positioning
• Correct disc alignment
• Strong structural support
• Reliable performance under load

XC3 Anodised Caliper Brackets

The XC3 caliper brackets are engineered to position the AP Racing CP9668 calipers correctly relative to the 368mm rotors.

Accurate caliper positioning helps maintain:

• Correct pad sweep
• Proper disc alignment
• Consistent brake geometry
• Reliable braking performance

AP Racing Floating Bobbin Hardware

AP Racing bobbin kits are included to mount the floating rotors correctly to the XC3 bells.

These components allow the disc and bell assembly to function as a proper floating brake system.

Braided Front Brake Lines

A pair of braided front brake lines is included.

Braided hoses can help reduce line expansion under pressure, contributing to a firmer and more consistent brake pedal feel.

Chemi Black High-Tensile Hardware

High-tensile Chemi Black caliper bracket hardware is also included.

This provides a strong and secure mounting solution for the brake conversion.

Improved Thermal Capacity

Track use places far greater demand on the braking system than normal road driving.

Higher speeds, more grip and repeated stops all generate substantial heat.

The combination of:

• 368 × 36 mm rotors
• Floating disc construction
• Six-piston CP9668 calipers
• 25mm endurance pads

creates a braking system designed to manage those loads more effectively.

Improved Braking Consistency

One of the key advantages of this setup is repeatability.

The kit is designed to provide more consistent braking throughout:

• Long track sessions
• Repeated high-speed stops
• High-grip tyre use
• Endurance-style driving

Reduced Risk of Brake Fade

Larger rotors and higher-capacity pads can help slow the rate at which braking performance deteriorates as temperatures rise.

This can improve confidence and consistency during prolonged hard use.

Ex-BTCC Rotor Condition

The supplied rotors are inspected ex-BTCC motorsport components.

Because these are previously used competition parts, cosmetic marks and visible signs of prior use should be expected.

This provides access to high-level motorsport hardware at a more cost-effective price than an equivalent fully new setup.

Ideal for Track-Focused S3 Builds

This kit is particularly well suited to:

• Audi S3 8P track builds
• Audi S3 8V track builds
• Clubsport cars
• Semi-slick tyre setups
• High-power road builds
• Long-session track use

Professional Installation Required

Professional installation is strongly recommended.

Braking systems are safety-critical and should be fitted by a suitably experienced technician.

Installation checks should include:

• Caliper alignment
• Rotor alignment
• Hardware torque
• Brake hose routing
• Pad sweep
• Wheel clearance
• Full system bleeding

Wheel Clearance

Wheel clearance must be checked before ordering.

Compatibility can depend on:

• Wheel diameter
• Spoke profile
• Offset
• Barrel clearance

Aftermarket wheels should always be checked carefully before purchase.

Vehicle Fitment

Compatible with:

• Audi S3 8P
• Audi S3 8V

What's Included?

• 2 x AP Racing CP9668 six-piston endurance calipers
• Choice of Nickel Plated or Anodised Grey finish
• 2 x Ex-BTCC 368 × 36 mm floating brake rotors
• 2 x XC3 anodised rotor bells
• 2 x XC3 anodised caliper brackets
• 2 x AP Racing floating bobbin kits
• 1 x Pair braided front brake lines
• Chemi Black high-tensile bracket hardware
• 1 x Set Pagid Racing RSL29 25mm endurance brake pads

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