You have no items in your shopping cart.
The factory C8 brakes can stop a Corvette. That's not the problem.
The problem begins when you add slicks, aero, speed, heat, and repeated high-energy braking events and then ask the system to deliver the same pedal, the same modulation, and the same confidence every single lap.
The AP Racing by Essex CP9660 Competition Brake Kit is built specifically for that job: six-piston Radi-CAL racing calipers, 18mm-thick motorsport pads, fully floating 372x34mm 72-vane AP Racing J-Hook discs, stainless pistons, anti-knockback technology, racing seals, and approximately 14 fewer pounds hanging from the nose than the factory Z51 brake package.
A driver can adapt to almost any reasonable brake torque. What destroys confidence is a pedal, bite point, or response that changes as the session progresses.
Caliper stiffness, stainless pistons, racing seals, and rigid lines reduce the variables between your foot and the brake pads.
Highly ventilated racing discs and proper motorsport pads are designed to absorb and reject enormous amounts of energy repeatedly.
A stiff caliper gives the driver a clearer relationship between pedal pressure and braking torque instead of hiding it behind component flex.
Pads, discs, seals, pistons, and other wear components are designed around the reality that race brakes eventually need service.
We ran AP Racing brake systems exclusively on our C5 race car for seven years. During that time, we never once gave serious thought to whether the braking system was capable of doing what we were asking from it.
We're now asking the same thing from a roughly 3700-pound C8 running slick tires and substantial aero. Still no drama.
That's really the highest compliment we can give a brake system. When you're hurtling toward a braking zone, you have plenty of things to think about already. Whether the pedal is going to be where you left it should not be one of them.
Traditional brake calipers tend to look like boxes because that's a convenient shape to manufacture.
AP Racing's Radi-CAL architecture instead puts material where the caliper actually needs it during a braking event. The asymmetric shape is designed around the dynamic loads trying to twist and distort the caliper while the pads clamp a rotating disc.
The result is an architecture with more than a 30% increase in static and dynamic stiffness compared with conventional caliper designs while simultaneously removing unnecessary mass.
The CP9660 weighs only about 6.2 pounds without pads despite carrying six pistons and enough brake capacity for serious competition use.
Less caliper deflection means less pedal travel wasted bending the caliper, better modulation, and more consistent pad contact across the disc.
The CP9660 weighs approximately 6.2 lb without pads versus roughly 11.1 lb for the factory Z51 front caliper.
No external crossover tubes means fewer vulnerable parts hanging off the caliper and more efficient packaging around the wheel.
The thinner 18mm-pad architecture gives the CP9660 substantially more wheel-spoke clearance than its big-pad CP9668 sibling.
AP uses machined stainless-steel pistons rather than aluminum. Stainless steel transfers heat far less readily, helping create a thermal barrier between the screaming-hot brake pad and the hydraulic fluid behind it.
The pistons are ventilated and use a domed-back architecture for additional stiffness.
Behind them sit anti-knockback springs. During hard cornering, hub and disc movement can push the pads and pistons backward into the caliper. The next time you hit the brake pedal, you first have to take up that unwanted clearance.
The springs help keep the pistons where they belong, reducing the dreaded surprise long pedal when you arrive at the next braking zone.
Virtually every major detail in the Pro5000R exists because brake temperature on track is dramatically different from anything encountered during normal road use.
Motorsport-style high-temperature piston seals are designed to survive repeated high-heat operation without becoming brittle.
Bellows-style dust boots can burn and deteriorate at racing temperatures. Pro5000R calipers simply eliminate them.
Electroless Nickel Plating provides a durable, easy-to-clean surface that handles the heat and abuse of competition use.
The CP9660 and CP9668 are extremely closely related six-piston Radi-CAL calipers. The meaningful difference is not brake torque or the number of pistons. It's how much brake pad fits between the two halves of the caliper.
Both versions use the same basic 152.1mm x 54mm pad footprint. The CP9660 uses an 18mm-thick pad. The CP9668 stretches that same pad architecture to 25mm.
Our default choice for conventional HPDE, time trial, and sprint-race use. An 18mm race pad still contains a tremendous amount of material, while the thinner caliper saves weight and gives you roughly 14mm more wheel-spoke clearance than the CP9668.
Designed for multi-hour endurance racing, extremely heavy pad consumption, or anyone willing to trade additional width and weight for fewer pad changes. Including the additional pad mass, the CP9668 setup is roughly one pound heavier and approximately 14mm wider.
AP designed the Pro5000R around frequent race-car maintenance.
The bridge hardware comes out with a simple 6mm hex wrench without removing the caliper from the car.
The design can also use AP's quick-change spring-clip bridge, making pad swaps absurdly fast. In many cases you'll spend more time removing the wheel than actually changing the brake pads.
The caliper gets most of the attention, but the disc is where the kinetic energy of the car actually becomes heat. Consequently, a huge amount of the engineering in this system lives in the rotor assembly.
The iron ring can grow radially as temperature increases without forcing the aluminum hat to follow that expansion, reducing coning, distortion, stress, and uneven pad contact.
Left- and right-specific curved internal vanes actively pump cooling air through the disc instead of relying on a simple non-directional internal structure.
AP's J-Hook slot pattern provides pad-face cleaning and bite while promoting more uniform thermal behavior across the disc face.
Heat-treated aluminum hats reduce unnecessary rotating mass while reducing heat conduction into the hubs and wheel bearings.
That sounds obvious, but accommodating thermal expansion is one of the fundamental differences between a serious racing rotor and a conventional one-piece road-car disc.
When a constrained iron disc heats and expands, it can distort into a cone. Once that happens, the pads are no longer meeting a flat disc. Pad taper, judder, inconsistent pedal travel, and cracking can follow.
AP's fully floating architecture allows the iron ring to expand relative to the hat while continuing to run true in the caliper. This is not a styling feature. It's how a racing disc survives repeated thermal cycles.
A common approach to building a "big brake kit" is simply to make everything enormous.
Essex takes the opposite approach: use enough brake to survive the job, then remove mass anywhere it isn't contributing to performance.
~14 lb lighterThe complete CP9660/372 front system removes approximately 14 pounds of unsprung mass from the nose compared with the factory C8 Z51 brake package.
Essex selects piston sizing specifically around the C8 so the front kit works with the factory hydraulic and electronic systems rather than treating the Corvette as a generic chassis with a brake bracket attached to it.
Caliper piston area is selected to work with the factory master cylinder rather than requiring a wholesale hydraulic-system redesign.
Piston sizing and brake torque are chosen to closely mimic the original axle relationship so the factory ABS system can remain.
The front CP9660 package can be installed with the OEM rear braking system or paired with the corresponding AP Racing by Essex rear kit.
Diameter is only half of brake-to-wheel fitment. Spoke shape and offset determine whether a wheel clears the outside face of the caliper.
The CP9660's thinner 18mm-pad architecture gives it approximately 14mm more spoke clearance than the CP9668, making it an especially attractive choice when you're trying to run smaller or lighter wheels.
Good news: the factory C8 19-inch Trident front wheel is a confirmed no-spacer fit with the CP9660 / 372mm package.
Essex has also confirmed several factory Z06 and Forgeline applications, but wheel fitment should still be physically verified for your exact wheel.
Download Wheel Fitment TemplateThe Pro5000R architecture prioritizes track performance, heat tolerance, low mass, rapid servicing, and pedal consistency.
That means features you might expect from an OEM street caliper—most notably external rubber dust boots—are intentionally absent. Competition pads can also make noise, and depending on pad dimensions and whether a tension kit is installed, some pad rattle may be present.
If your priority is silence, road salt, winter corrosion protection, and never thinking about brake maintenance, you're looking at the wrong category of brake system.
If your priority is repeated braking at race-track temperature, you're in exactly the right place.
We actually prefer it that way.
Brake compound selection depends enormously on tire, vehicle weight, track, driver, session length, temperature, and personal preference. Stuffing a generic set of pads in an expensive race brake kit simply so the box can say "pads included" doesn't do anyone a favor.
The CP9660 uses one of the most common large motorsport pad shapes on the market, allowing you to choose the compound that actually makes sense for your car.
We stock G-LOC pads specifically for the CP9660 / CP9661 family in the proper 54mm radial depth and 18mm thickness. Our pads are also supplied without the retention eyelet that otherwise needs to be ground or cut off for use in the Pro5000R caliper.
Pad-tension / anti-rattle hardware is optional rather than included. This allows the caliper to accommodate pads from a wide range of manufacturers while giving customers who care about paddock or street NVH an additional noise-control option.
Shop G-LOC Pads For CP9660 / CP9661Read the complete Essex C8 front-brake installation procedure before taking the car apart. One particularly important C8-specific step: disconnect the battery before opening the hydraulic system.
View Installation Guide →Print the template at 100% scale and physically check your wheel. Wheel diameter alone does not guarantee spoke clearance around a brake caliper.
Download Fitment Template →These kits are expensive. So are tires, entry fees, engines, bodywork, and mistakes caused by arriving at a braking zone without complete confidence in the pedal. AP Racing Competition systems are built so the brakes become one less variable between you and a fast lap.
