AP Racing CP9448 4-Piston Caliper with StopFlex Carbon Ceramic Brake Disc Big Brake Kit
Official Warranty: 1‑year free replacement for quality defects or coating issues under normal (non-track) use.
StopFlex Carbon Ceramic Brake Disc Kit (C/SiC) + AP Racing CP9448 4-Piston Calipers
A competition-ready front brake upgrade. This kit combines the AP Racing CP9448 4-piston caliper with StopFlex carbon-ceramic technology. Engineered for lightweight performance cars, it delivers a massive reduction in unsprung weight and exceptional fade resistance.
What changes for you (real-world):
- Massive weight reduction: The carbon-ceramic system is typically ~40–50% lighter than iron equivalents, sharpening steering response and suspension compliance.
- Precise Modulation: The AP Racing CP9448's rigid forged body delivers superior pedal feedback compared to OEM sliding calipers.
- Fade-free performance: Discs engineered to remain stable at temperatures near 900°C.
- Longer service life: Discs target 250,000–300,000 km in typical road use, with no flash rust or corrosive brake dust.
Fitment confirmation (we keep it simple):
- Year / Make / Model / Wheel Size (VIN helps)
We engineer the brackets, hat offsets, and disc dimensions (355–440 mm) to fit your specific vehicle hub and wheel clearance.
Bolt-On Package List
| Item | What it is | Why it matters |
|---|---|---|
| AP Racing CP9448 4-Piston Calipers | Genuine fixed forged aluminum calipers (Front Axle). | Robust 4-piston design optimized for performance road and track use; provides excellent control and even pad pressure. |
| StopFlex Street Carbon Ceramic Discs (C/SiC) | Long-fiber carbon-ceramic friction rings engineered for road use. | Delivers high friction stability, massive weight savings, and resistance to thermal shock. |
| StopFlex CNC-machined Aluminum Hats | Precision hats matched to your vehicle's hub. | Ensures correct offset and alignment for a true bolt-on installation. |
| StopFlex CCB-optimized Pad Set (Match Your Calipers) | Pad compound specifically formulated for carbon-ceramic discs. | Prevents noise and accelerated wear issues common with mismatched pads; tuned for strong cold bite. |
| Mounting Brackets & Hardware | Application-specific CNC brackets and high-grade bolts. | Adapts the radial-mount AP Racing caliper to your vehicle's knuckles securely. |
Carbon-Ceramic vs. Cast-Iron / Steel Discs
| Item | StopFlex Carbon-Ceramic (C/SiC) | Cast-Iron / Steel Disc |
|---|---|---|
| Typical disc weight (same size class) | Often about ~50% lighter than steel/iron discs of similar size. | Heavier rotating mass at the wheel. |
| Service life (typical road use) | 250,000–300,000 km target for typical road use (conditions matter: vehicle weight, driving style, pad choice). | Common guidance is ~30,000–70,000 miles (≈48,000–113,000 km), strongly usage-dependent. |
| Corrosion & appearance | No flash rust; stays visually clean behind the wheel. | Surface rust after rain/storage is normal; cosmetic “orange” is common. |
| High-temperature stability (material + failure modes) | Carbon-ceramic discs are built to remain structurally stable under repeated high-energy stops. Common “wrong-use” risks are impact damage (chips) and pad mismatch. | Cast iron is robust for road use, but high disc temperatures can lead to hot spotting, thermal cracking, and fade. Dynamometer testing for gray cast iron discs commonly reaches ~600°C range before issues arise. |
| Heat flow & cooling needs (why ducts matter) | Lower thermal conductivity means more heat stays near the friction surface. Perfect for street/short stints, but long lapping sessions need better ducts/venting so fluid doesn't cook. | Grey cast iron has relatively high thermal conductivity, allowing heat to spread quickly into vanes/airflow. Helps with steady heat dumping until the system is overwhelmed. |
Choose Your Disc Style
Three variants built around the same long-fiber carbon-ceramic core. Pick the one that matches how you actually drive.
Street
- Face design: Drilled + Big Cooling Holes
- Cooling core: Directional internal venting
- Coating: Ceramic coating (street durability + clean look)
- Use: Daily, canyon runs, highway pulls, short light track sessions
Track-Day
- Face design: Blank + Hive Cooling Holes
- Cooling core: Hive-style internal cooling
- Coating: Ceramic coating (balanced street + heat tolerance)
- Use: Street + occasional track days (best with proper brake ducts)
Race-Only
- Face design: Blank + Hive Cooling Holes
- Cooling core: Hive-style internal cooling
- Coating: No coating (race-focused surface)
- Use: Dedicated track/race cars with strong cooling and regular inspections
Note: Not intended for street use.
Technical Specifications
| Caliper spec | AP Racing CP9448 (4-Piston), forged aluminum fixed body, radial mount. |
| Disc material | StopFlex carbon-ceramic composite (C/SiC), street-focused surface engineered for road use. |
| Disc diameter range | 355–440 mm (application-specific). |
| Construction | Two-piece floating disc system with StopFlex CNC-machined Aluminum Hats. |
| Pad set | StopFlex CCB-optimized Pad Set (Match Your Calipers). |
| Kit compatibility | Custom engineered for your specific Year/Make/Model to ensure caliper clearance and hub fitment. |
Specs are finalized per vehicle. We prefer “correct fitment + correct pad match” over generic claims.
FAQ
Is this a universal kit?
No. While the calipers are AP Racing CP9448, the mounting brackets and hats are custom-machined. We confirm your Year / Make / Model / Wheel Size (VIN helps) to build a kit that bolts directly to your specific spindle.
Will it work from cold on the street?
Yes. We pair the discs with a StopFlex pad compound designed for street use. You get immediate bite without needing to "warm up" the brakes, even in sub-zero winter conditions.
How long do the discs last?
For typical road use, StopFlex targets 250,000–300,000 km. Heavy track use will reduce this lifespan, but they still significantly outlast iron rotors under similar stress.
Can I use any pad that fits the CP9448 caliper?
Physically yes, but we strongly advise against it. Standard organic or semi-metallic pads meant for steel rotors can damage the carbon-ceramic surface or cause noise issues. Always use the StopFlex CCB-optimized Pad Set.
Do I need to change my master cylinder?
In most cases, no. We calculate the piston area to work with your factory hydraulic system. We recommend a full fluid flush with high-temp brake fluid during installation.
Is there a bed-in process?
Yes. A controlled bed-in builds a consistent transfer layer on the disc. We include a specific procedure with the kit (moderate stops, then cool-down) to ensure optimal performance.
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