BMW M2 / M3 / M4 F80 F82 F83 F87 – BTCC Big Brake Kit – AP Racing CP9660 Complete Upgrade | XC3 Engineering
Unlock serious track-day performance with the XC3 BTCC Big Brake Kit for the BMW M2, M3 and M4 F8X chassis. Designed around the proven AP Racing CP9660 caliper and paired with our CNC-machined bells and carriers, this complete package gives the F8X platform the stopping power it deserves.
The F8X cars are heavier, turbocharged, and place greater thermal load on the front brakes compared to earlier generations. This kit solves the F8X braking weakness by delivering stronger bite, improved pedal consistency and high-temperature endurance, perfect for track, clubsport or fast-road builds.
Kit Contains:
- XC3 Engineering custom anodised rotor bells
- XC3 Engineering custom anodised caliper brackets
- Chemi black bracket hardware
- 2x AP Racing 6 piston Pro 5000 series R calipers CP9660
- Braided brake lines
- 2x AP Racing Bobbins kit
- 2x ex-BTCC 368mm x 36mm rotors
- Ex-BTCC brake pads Raybestos ST45 (Project MU H21 also available please contact us)
The BTCC rotors are previously used components. AP Racing do not offer this rotor size for public sale, as it is exclusively provided to BTCC teams. The rotors we supply have been used during a single session at a BTCC event and have undergone inspection to confirm they are in proper working order.
Pads are also used items, this again keeps our kit as cost effective as possible when replacing considerable parts.
RayBestos ST45 & Project Mu H21 comparison
| Attribute | Raybestos ST45 | Project Mu H21 |
|---|---|---|
| Pad Compound / Material | Mid-to-high performance racing compound, established racing pad material. | High-end carbon-ceramic racing compound, competition-only spec. |
| Intended Use | Endurance, heavy braking road-course racing, clubsport, track days — good balance of performance and rotor/ pad wear. | Motorsport / racing: GT, road course, short-oval, high-demand braking environments; “competition-only” pad. |
| Operating Temperature Range (Rotor) | – 700 °C | 200 °C – 850 °C |
| Friction / Bite & Brake Feel | Consistent, predictable mid-to-high friction — good modulation and stable performance under repeated heavy braking. | Very aggressive, track-optimised friction; strong bite and fade resistance, stable through high heat cycles. |
| Rotor / Pad Wear & Rotor Friendliness | Lower wear rate compared to aggressive race pads; relatively rotor-friendly - a good compromise for clubsport/use with repeated calls. | According to manufacturer - “very kind to the rotor,” even under high stress braking, despite high performance. |
| Use-Case Strengths | - Clubsport/track-day cars that also see occasional road use - Situations needing consistent, repeatable braking under repeated heavy use - Good balance between performance & maintenance (rotor/pad wear) | - Full-on track cars, racing builds (GT, Time Attack, sprint, oval) - High-heat endurance or repeated hard braking - Builds where maximum braking performance is required and pad/rotor wear is accepted as part of use |
| Trade-offs / Considerations | Slightly less aggressive bite than “pure race” pads — may be less dramatic initial feel in very aggressive braking; but good balance overall. | As “competition-only” pad — may be noisy, dusty; cold-bite may be less predictable; less ideal for regular street use; pad/rotor wear may be more demanding. |
Fitment:
BMW M2 M3 M4 F8X with OEM front Hubs
Please note these kits are made to order. We aim to keep everything in stock but some items may have a lead time. Please contact us for availability.