What is the difference between AP Racing Competition and Road brake kits?

Competition kits are built for track use — they feature anodized calipers with stainless steel pistons (no dust boots), anti-knockback piston springs, and high vane count floating discs optimized for weight. Pads and fluid are not included so drivers can choose their preferred compounds. Road kits are designed for street-driven cars with occasional track use — they have painted calipers with aluminum pistons and dust boots for weather protection, include sport pads and fluid, and come with one-piece or two-piece disc options.

What is the AP Racing Radi-CAL caliper and why is it better?

Radi-CAL is AP Racing's patented asymmetrical caliper design using advanced FEA modeling to redistribute material based on dynamic loads. Compared to traditional calipers, Radi-CAL delivers 30%+ greater stiffness, 33% less deflection, and significantly lower weight — the CP9660 weighs just 6.13 lbs and the CP9668 just 6.83 lbs. This translates to better pedal feel, more consistent braking, and improved thermal management. Radi-CAL technology is used in Formula 1, NASCAR, and nearly every major professional racing series.

What does the ENP finish mean on AP Racing calipers?

ENP stands for Electroless Nickel Plating — a hard, corrosion-resistant nickel coating applied to the caliper body. ENP provides superior environmental protection compared to standard anodizing, making it the ideal choice for cars that are driven on the street and see track days. The distinctive silver-nickel finish gives a clean, factory-quality look behind the wheel.

Which AP Racing caliper should I choose — CP9660 or CP9668?

The CP9660 is a 4-piston Radi-CAL caliper and the CP9668 is a 6-piston Radi-CAL caliper. The CP9668 offers more clamping force and a larger pad contact area, making it the better choice for heavier vehicles, high-horsepower builds, or dedicated track cars. The CP9660 is lighter and more compact — ideal for builds where weight savings and packaging are priorities. Both use the same Radi-CAL Pro5000R technology with identical stiffness and thermal advantages.

Will an AP Racing big brake kit fit my stock wheels?

Most AP Racing by Essex big brake kits require a minimum wheel diameter of 18 inches, with some larger kits requiring 19 or 20-inch wheels. Wheel spoke design, offset, and width all affect clearance. Essex provides detailed fitment guides with caliper-to-wheel clearance diagrams for every kit. Always verify wheel clearance before purchasing. Our team at FFP can help you confirm fitment — call 805-206-2523.

Do I need to upgrade my rear brakes if I upgrade the front?

Not necessarily, but it's recommended for the best braking balance. Upgrading only the front shifts the brake bias forward, which can cause the rear end to become unstable under heavy braking — especially on track. Essex offers matched front and rear kits for most applications to maintain proper brake proportioning. For street-only use, a front-only upgrade is common and effective.

Does Function Factory Performance install AP Racing brake kits?

Yes — our Thousand Oaks, California shop (49 Taylor Ct, Unit B) offers professional installation of all AP Racing by Essex brake kits. Brake kit installation is precision work that includes caliper alignment, rotor runout measurement, line routing, bleeding, and proper pad bedding. Our technicians have hands-on experience installing these kits on Mustangs, BMWs, and McLarens. Call 805-206-2523 to schedule installation.

Are AP Racing by Essex brake kits street legal?

Yes. Both the Road and Competition kits are street legal. The Road kits are specifically designed for daily-driven vehicles and include dust boots, weather sealing, and street-oriented pads. Competition kits are also street legal but lack dust boots and weather protection — they're better suited for cars that see primarily track use. All kits meet or exceed OEM braking standards.