AP Racing ⨉ Essex CP9668 Radi-CAL Competition Front Brake Kit for RZ34 Nissan Z

AP Racing ⨉ Essex CP9668 Radi-CAL Competition Front Brake Kit for RZ34 Nissan Z

Elevate your RZ34 Nissan Z’s front braking performance with the AP Racing ⨉ Essex CP9668 Radi-CAL Competition Front Brake Kit. Despite its larger size, this game-changing kit saves over 25 unsprung lbs. from the car’s nose compared to OEM brakes. At the heart of the kit are the AP Racing CP9668 Radi-CAL Pro5000R six-piston calipers, optimized for performance. The kit features 372x34mm, 72 vane AP Racing discs and employs 25mm (1 inch) thick brake pads, each component meticulously designed to resist the heat of extended track sessions. With pistons appropriately sized for a seamless fit with the OEM master cylinder and ABS system, this kit ensures flawless integration and superior performance. Perfectly compatible with either the OEM rear brakes or the AP Racing by Essex Rear Brake Kit, this front brake kit delivers unmatched braking performance, transforming your ride into a true track-ready machine.

Radi-CAL

• AP Racing has brought about a revolution in brake technology through its patented Radi-CAL asymmetrical brake caliper design. This groundbreaking advancement relies on state-of-the-art technologies like Computer Aided Design (CAD) and Finite Element Analysis (FEA). Unlike traditional designs from the past, this modern technology enables the creation of uniquely unconventional calipers with an organic shape that pushes the boundaries of innovation. Radi-CAL calipers, widely recognized as the epitome of brake caliper technology, have consistently set new benchmarks since their introduction in 2007. Their outstanding performance has been demonstrated on race tracks across various professional motorsport levels, earning numerous victories and establishing their reputation as a game-changer in brake performance.
• Benefits of the Radi-CAL Design
  • Significant Stiffness Enhancement – The Radi-CAL calipers demonstrate a significant improvement in stiffness, surpassing conventional calipers with a remarkable increase of over 30% in both static and dynamic stiffness. This enhanced stiffness plays a crucial role in minimizing deflection when subjected to loads, resulting in superior pedal feel, precise modulation, even pad wear, and an extended lifespan for the caliper.
  • Substantial Weight Reduction – Additionally, the Radi-CAL design achieves a substantial reduction in weight by eliminating unnecessary caliper mass, despite the notable increase in stiffness. This reduction in weight contributes to improved overall performance.
  • Optimized Airflow – To optimize airflow, the Radi-CAL calipers are meticulously engineered, allowing air to circulate more efficiently around and through the caliper. This efficient airflow facilitates superior heat evacuation and cooling, thereby enhancing the overall brake performance.
  • Efficient Packaging – The thoughtful design of the Radi-CAL caliper includes an asymmetric profile and internal fluid porting, enabling efficient packaging. This design allows for more flexible installation options in tight spaces without compromising performance.

CP9668 PRO5000R Calipers – The Everyman Radi-CAL

• The highly anticipated Radi-CAL Pro5000R brake caliper is now available, representing years of continuous evolution and refinement. These calipers offer exceptional high-performance capabilities suitable for racers of all experience levels. Drawing inspiration from F1 and Sprint Cup technology, the design philosophy behind these calipers transcends the ordinary by combining lightweight construction with functionality and aesthetic appeal.
• Advancements in manufacturing techniques have made the Pro5000R calipers more accessible and convenient without compromising their peak performance capabilities. Previously, these intricate calipers were crafted from expensive proprietary aluminum alloy billets, which made them prohibitively expensive for average club racers, time-trialers, or HPDE participants. However, a breakthrough in manufacturing has been achieved with the Pro5000R calipers utilizing a new drop forging operation. This significant improvement has led to a substantial reduction in production expenses and, consequently, the entry cost for these calipers.
• As a result, this remarkable technology is now within reach for a wider audience, enabling more individuals to experience the benefits and performance advantages offered by these technologically advanced brake systems. Whether you’re an enthusiastic club racer or someone eager to hit the track, the Radi-CAL Pro5000R calipers present an ideal choice.

Radi-CAL = Massive Dynamic Stiffness Increase

• Over the years, various approaches have been employed to reduce the size of brake calipers while ensuring sufficient stiffness. These strategies have involved robust caliper bridge designs, two-piece calipers with steel through-bolts, the utilization of exotic materials such as Beryllium and MMC, forging instead of casting, and the adoption of monobloc designs. All these innovations aimed to make calipers lighter, smaller, and stiffer. Despite these efforts, the traditional rectangular, boxy shape continued to be the accepted norm for calipers.
• AP Racing has challenged the conventional belief that a rectangular box is the most efficient shape for a brake caliper. They have demonstrated that the traditional design is not optimal. When a caliper clamps brake pads against a rotating disc, a substantial tangential friction force is generated between the pads and the disc. This force pulls the caliper strongly toward the spinning disc, and the caliper withstands this force through its rigid mounting points on the spindle.
• During braking events, the caliper experiences dynamic loads that cause it to twist or deform into a parallelogram shape. AP Racing recognized the significance of this dynamic force and specifically designed the Radi-CAL caliper to address it. Unlike traditional calipers that were designed without full consideration of the forces they would encounter, the Radi-CAL caliper was intentionally created with a deep understanding of the forces present during braking events.
• The Radi-CAL caliper optimally distributes its mass diagonally rather than concentrating it at the ends of the caliper. This design enables the caliper’s mass to effectively support the forces acting on it during braking, rather than relying solely on an empty box structure. Additionally, this redistribution of mass allows for a substantial reduction in overall weight by eliminating non-essential, non-load-bearing material from the caliper body.
• WHAT DOES THE ABOVE MEAN FOR YOU, THE DRIVER? IT MEANS A SIGNIFICANTLY FIRMER BRAKE PEDAL WITH SUPERIOR MODULATION UNDER ALL CONDITIONS. IT ALSO MEANS MORE EVEN PAD WEAR WITH LESS TAPERING, AND A LONGER CALIPER SERVICE LIFE.

Radi-CAL = Ultra-Lightweight, Compact Design with High Airflow

• As mentioned earlier, the Radi-CAL design philosophy considers not only what is present but also what is absent. The intentional redistribution of caliper mass creates voids in unconventional areas. This strategic removal of mass from the caliper body optimizes its overall shape, resulting in an impressively lightweight and compact size. While competing six-piston calipers typically weigh between 9 to 12 lbs, the CP9668 weighs an astonishingly low 6.8 lbs.
• The approach to brake kit design by Essex has always prioritized efficiency, recognizing that anything larger than necessary adds unnecessary weight. The Radi-CAL caliper perfectly aligns with this philosophy. Many brake packages on the market face challenges with wheel fitment due to oversized discs and 12-piston calipers. This can make it difficult to fit them behind OEM wheels or lightweight alternatives. The goal is to reduce unsprung weight and enable the use of smaller, lighter wheels that are more readily available and cost-effective when paired with R compound tires. Properly designed components that prioritize performance eliminate the need for excessively heavy calipers. Concerns about stiffness resulting from mass reduction are unfounded. AP Racing’s Pro5000R calipers are not only lightweight but also incredibly stiff, specifically designed for racing applications.
• A notable feature of the Pro5000R range is the placement of the bleed screws and fluid pathways. The calipers incorporate internal fluid porting, with only two bleed screws positioned on the inner caliper half. This configuration minimizes the risk of damaging a bleed screw or crossover pipe during wheel changes. Additionally, it reduces the number of bleed screws that require attention during brake fluid replacement. The absence of external piping and bleed screws also allows for rounded outer corners, improving clearance with wheel spokes.
• Compared to traditional calipers, the design of the Pro5000R enhances airflow between and around the pistons and brake fluid pathways. This improved airflow contributes to better overall system operating temperatures, leading to enhanced performance and durability.

Two-Piece, Drop-Forged Caliper Body

• Traditionally, calipers have been manufactured using a monobloc design, which involves machining them from a single, solid block of proprietary aluminum alloy. This design restricts the machining of piston bores and piston seal grooves to right-angle machine tools that need to be inserted into the caliper. The process of removing all the material and achieving the final shape through specialized tools and multiple setups is time-consuming and expensive. As a result, monobloc Radi-CAL calipers have been priced beyond the reach of the average club racer, time-trialer, or HPDE participant.
• However, the introduction of a new two-piece drop-forging process has made the Pro5000R caliper a reality. This innovative manufacturing technique enables conventional machine tools to directly access the piston bores. As a result, there has been a significant reduction in production time and cost while maintaining an exceptionally rigid structure. This advancement has made the Pro5000R caliper more accessible to a wider range of users, eliminating the cost barrier previously associated with monobloc calipers.

Hard Anodized Finish

• One of the initial weaknesses that stands out in many aftermarket calipers is the finish, usually done with paint in various colors for aesthetic appeal and protection against harsh winter weather corrosion. However, for all its visual appeal, painted calipers have a downside when used in track environments, where heat leads to the finish rapidly deteriorating — chipping, fading, or even changing color — sometimes over a single weekend. The result is an unpleasant hue and the unwanted scattering of paint chips.
• This issue stems from the inability of paint and powder coatings to endure the intense heat experienced during track use. Powder coatings, in particular, can expand with the heat and then fail to contract properly as the caliper cools, resulting in a cracked and loose coating. Paint, depending on its application, can have similar problems. Variations in application can lead to differences in coating thickness, color shades, and consequent issues like cracking, flaking, and inadequate protection of the underlying metal. Additionally, both paint and powder coatings undergo extreme color shifts when heated — red to maroon or black, gold to brown, and black simply deteriorates.
• The calipers used in the Essex Radi-CAL Competition Kits, on the other hand, are not only ultra-lightweight and sturdy under all track conditions, but also feature a hard anodized finish. This finish takes advantage of the natural oxidation process that forms a protective layer on aluminum when it reacts with oxygen in the air — similar to rust formation. By enhancing this process using an electrical current through an acid bath and adding color dyes, the anodizing process results in an extremely durable layer of aluminum oxide.
• This anodized finish is far more suitable for track use, offering a more abrasion-resistant surface than either paint or powder coating. As a result, it won’t chip off as easily when the caliper is struck with a tool, like a wrench, during maintenance. While anodized calipers can still change color when heated, it takes significantly more heat to trigger the change and the color shift is not as dramatic. Most importantly, you won’t have to deal with bits of anodized coating sticking to your pistons.

Ventilated, Domed Back, Stainless Steel Pistons

• There are arguments suggesting that aluminum pistons are ideal for track calipers, asserting that the expansion rates of the pistons and caliper body should be identical when heated. However, these claims lack substantiation and evidence. In reality, all reputable manufacturers of race calipers worldwide exclusively utilize stainless steel or titanium pistons in their high-performance calipers. This preference is based on the proven superiority of stainless steel pistons.
• Stainless steel pistons excel at creating a thermal barrier, effectively reducing heat transfer to the brake fluid and preventing a soft pedal caused by fluid fade on the track. This exceptional performance has been consistently demonstrated across various levels of motorsport. While most aftermarket calipers rely on pressed aluminum pistons, the Pro5000R calipers feature meticulously machined stainless steel pistons, which are more expensive but offer superior benefits.
• To enhance piston stiffness, AP Racing has incorporated a domed shape at the back of the piston. Despite being a seemingly small design element, the introduction of domed back pistons in professional racing received immediate and overwhelmingly positive feedback from drivers. The domed back significantly increases stiffness, resulting in a tangible improvement felt through the pedal. As a result, this design has become the benchmark against which all other designs are measured.
• For enhanced heat resistance, the pistons in the Pro5000R calipers are equipped with ventilation. Air gaps around the edges of the piston facilitate additional air circulation, contributing to the cooling process around the pistons. These features collectively work to slow down and repel the influx of heat into the brake fluid, effectively preventing brake fluid boiling and fade under demanding conditions.

Anti-Knockback Springs

• AP Racing calipers incorporate stainless steel pistons with anti-knockback (AKB) springs. While it may be surprising to find springs in pistons, they serve a crucial purpose. Knockback, which causes the pedal to drop after a series of S turns when entering a brake zone, can be unsettling. Knockback commonly occurs with fixed calipers when the wheel, hub, and bearings deflect during cornering, causing the brake disc to become misaligned with the caliper and brake pads.
• To address this issue, the pistons in AP Racing calipers are equipped with AKB springs. These springs exert tension on the backside of the pistons, helping to push them back into their proper position when the disc deflects and comes into contact with the pistons. By reducing the slack in the system, the AKB springs minimize pedal drop and provide a more reliable braking experience, particularly in heavy brake zones.
• When properly designed and integrated into the caliper, lightweight AKB springs do not cause increased drag or wear on the pads and discs. It is essential to consider the shape and material of the piston seals to ensure optimal performance. The seals in the caliper can be thought of as a spring or hinge attached to the side of the piston rather than just a ring through which the piston slides. The seal deforms slightly due to friction between the outer piston wall and the seal as the pistons slide in or out.
• The inclusion of AKB springs adds a slightly higher force requirement to push the pistons back into their bores compared to without the springs. Once the springs are compressed, they unload and push the piston back to the ‘neutral’ position. Properly designed seals and springs aim to keep the piston in the ‘neutral’ position, not pressed against the disc. The piston can still slide freely in either direction, but initial friction or tension must be overcome to initiate movement. The seal provides this initial friction to limit movement, and the spring adds additional resistance. Consequently, properly designed AP Racing calipers do not drag or cause unnecessary wear.

High Temperature, Low Drag Seals Without Dust Boots

• Essex frequently encounters a surprising question from potential customers regarding the maintenance and rebuilding of calipers in their kits due to the absence of dust boots on the pistons. This question puzzles them because it lacks intuitive reasoning. If a product is specifically designed to withstand the extreme high-heat conditions of track use, it should require less maintenance compared to brake components intended for low-speed and low-temperature street driving.
• It is important to clarify the distinction between piston seals and dust boots, as confusion often arises. All calipers have seals, which are the small rubber rings inside the piston bores. These seals prevent brake fluid from leaking around the pistons. OEM caliper seals are not designed to endure constant exposure to high temperatures without becoming brittle and leaking. However, Essex’s calipers utilize high-temperature seals identical to those used in NASCAR Sprint Cup, ALMS, DTM, and other professional racing series. These high-temperature seals are less prone to becoming brittle and wearing out under the demanding track conditions, resulting in significantly reduced replacement and servicing needs.
• Most aftermarket calipers are designed for year-round road use and come equipped with external dust boots, as illustrated in the example provided. These rubber boots stretch as the pistons extend, aiming to keep contaminants out of the piston bore. While this concept may seem appealing, Essex has observed instances where customers have burned through these boots in a single 20-minute track session. Once the boots are damaged, the pistons are left with tattered and burnt rubber fragments that provide no benefits. Considering the boots are quickly destroyed during track use, it becomes unnecessary to include them in the design, eliminating the mess they create.

Simple Pad Change with Two Bolts, or Quick-Change Spring Clip (CP9668 only)

• When the time comes to replace your brake pads, it’s understandable if you’re not particularly thrilled about the task. However, with the Pro5000R calipers, changing brake pads will no longer be a chore. Say goodbye to struggling with hammers, punches, or pliers. AP’s bridge bolts can be effortlessly removed using a 6mm hex wrench. With this easy removal process, changing pads will be quicker than ever before. In fact, you’ll spend more time removing the wheel than actually swapping out the pads. This means less time fussing around in the paddock and more time enjoying the exhilaration of driving.
• The convenience of the CP9668 caliper extends even further with the inclusion of two bridge options as standard. You can choose between the fixed bridge or utilize the quick-change spring clip that comes with the caliper. Opening the spring clip is as simple as squeezing and lifting. This innovative feature makes changing pads faster and easier than ever before.

Pistons Sized Specifically for Your Car

• The brake systems are meticulously designed to ensure that the sizes of the pistons closely align with the OEM brake torque on a specific axle. This careful selection enables front systems to be seamlessly installed on stock cars without causing any adverse effects or negative impact on the ABS system. There is no requirement to replace the stock master cylinder or the OEM rear brake system, making the installation process straightforward and hassle-free.

Lifetime Professional Reconditioning Service

• Essex is the designated caliper reconditioning center for AP Racing in North America, fulfilling an official role. Their team of highly skilled service technicians possesses expertise in the rebuilding process of numerous AP Racing calipers every year. These calipers are primarily serviced for renowned motorsport teams, including those participating in prestigious events such as NASCAR Sprint Cup and ALMS.
• Removal and Shipping – To initiate the reconditioning process, simply remove your calipers from the vehicle, ensure they are drained and cleaned, and ship them back to Essex.
• Hardness Testing – Once disassembled, your calipers undergo Rockwell hardness testing to evaluate fatigue and stiffness loss. This comprehensive test helps us assess the extent of wear and determine whether the calipers should be replaced or rebuilt. Fatigued calipers can lead to issues such as pad tapering, increased pad wear, leaky seals, and diminished pedal firmness.
• Ultrasonic Cleaning – Calipers that pass the hardness test undergo a meticulous cleaning procedure in Essex’s state-of-the-art ultrasonic cleaner. This advanced process ensures the removal of all dirt, debris, and brake fluid, surpassing the effectiveness of traditional hand-cleaning methods.
• Inspection and Re-Assembly – All serviceable components of the caliper, including seals, abutment plates, pistons, and bleed screws, are thoroughly inspected and replaced as needed to guarantee optimal performance.
• Cyclical Pressure Testing – After the calipers are rebuilt, they undergo rigorous cyclical pressure testing on a specialized bench. This intensive testing procedure ensures proper functionality and identifies any potential leaks that may only manifest under specific pressure conditions.

Discs – AP Racing Competition J Hook

• The AP Racing J Hook discs included in this system are the epitome of endurance racing excellence. These exceptional components are purpose-built to endure the most rigorous conditions you can expose them to. Renowned for their exceptional durability, these discs have a well-established history in professional racing, boasting multiple victories and championships in esteemed events such as ALMS, Rolex, Grand Am, and others. With their remarkable performance and proven reliability, the AP Racing J Hook discs are the ideal choice for drivers who prioritize top-notch performance and long-lasting reliability in their racing pursuits.

Two-Piece Floating Design with Aluminum Hat

• When exposed to heat, iron brake discs, like most metals, undergo significant expansion. This expansion causes the diameter and circumference of the disc to increase. For one-piece disc designs, this expansion poses a challenge. In the provided image, envision the disc being heated during track use. As the disc expands, the outer edges pull away from the center without any provision to accommodate this expansion. Consequently, the edges of the disc distort and lift, leading to a phenomenon known as coning. Now, imagine the disc mounted vertically in your caliper. Coning directly impacts the contact between the brake pads and the disc, resulting in uneven wear, tapering, and a longer brake pedal.
• In contrast, two-piece discs are specifically engineered to compensate for disc expansion when exposed to heat. This compensation is achieved by incorporating “float” into either the disc itself or the disc hat/bell. In the provided image, the float is integrated into the disc. If you closely observe the picture, you’ll notice that the mounting holes for the hat attachment bobbins are not circular but oblong in shape. These oblong channels enable the hat mounting hardware to slide as the disc heats up and expands. This sliding movement allows the disc to maintain its true position within the caliper without distortion. By adopting this design approach, distortion, stress cracks, and pad taper are minimized, ensuring optimal performance and longevity of the braking system.

Mounting Hardware and Anti-Knockback Spring Clips

• When closely examining the mounting hardware used in Essex’s Competition Kits, you will discover several often overlooked details that distinguish them from inferior products. These components are intentionally designed and not generic bolts sourced from a local retail store. They are custom-made exclusively for Essex and AP Racing in the USA, the same components employed in professional racing applications.
• As mentioned earlier in reference to the piston springs, knockback can present a significant concern when driving on the track. To effectively manage the lateral movement of the disc, which can push the pistons back into the caliper, we utilize anti-knockback spring clips at every alternate disc attachment point. For instance, a ten-bolt disc assembly would incorporate five spring clips, while a twelve-bolt disc would feature six. These spring clips ensure the alignment between the disc hat and the iron ring is maintained while still allowing radial expansion and floatation of the disc. Additionally, they offer the added advantage of preventing any rattling or noise from the disc hat and iron disc assembly.

Hat Design

• In addition to their various advantages, floating two-piece discs offer the additional benefit of minimizing heat conduction to the hubs and bearings. This reduction in heat transfer helps reduce wear and tear on these crucial components, ultimately contributing to their prolonged lifespan. The disc hats, which play an integral role in the assembly, undergo meticulous craftsmanship using 6061 heat-treated billet aluminum. This ensures exceptional strength, even in high-temperature conditions. To further optimize their performance, the hats are treated with a hard anodized coating. The choice of material and coating is specifically tailored to withstand the intense heat generated by the iron discs. Notably, the hats are designed with scallops on the underside, facilitating effective heat dissipation along the outer face of the disc once they are installed.

Internal Vane Quantity and Quality

• The internal vane design of AP J Hook discs distinguishes them from OEM-style discs and other aftermarket brands. Unlike the pillar vane designs commonly found in OEM discs, AP Racing discs utilize a different approach. Pillar vanes consist of interconnected posts or pillars that connect the two halves of the disc, creating turbulence as air flows through them. This design prioritizes disc face stability and cost efficiency rather than efficient heat evacuation. Some OEM discs feature straight, non-directional internal vanes, which offer better airflow than pillar vanes but still fall short of the directional vanes employed in AP Racing discs.
• AP Racing discs feature directional vanes that optimize airflow by spinning in a specific direction, maximizing the amount of air passing through the disc. Each pair of AP Racing discs is specifically designed for a particular side and cannot be swapped. The vane orientation and shape are precisely engineered to promote smooth airflow and enhance cooling performance.
• Furthermore, AP Racing discs surpass many aftermarket discs in terms of vane count. While most aftermarket discs have 30 to 48 vanes, AP Racing’s J Hook discs boast a higher vane count, typically ranging from 60 to 84 depending on the application. The increased vane count enables higher airspeed, improved heat transfer, reduced air recirculation between vanes, and minimized deflection at the disc face. Compared to OEM-style or competitor’s 48 vane discs, the 60+ vane discs offered by AP Racing demonstrate enhanced resistance to coning, distortion, and cracking. They also provide benefits such as reduced brake fade, minimized judder, more consistent pad contact, and extended service life.
• By comparing the internal vane designs, one can observe the distinctive features of the AP Racing J Hook disc. Notably, the AP Racing disc exhibits a wider air gap between the disc faces, allowing for significantly increased airflow into and through the disc. The uniform and directional vane design further contributes to superior airflow performance.
• It is worth noting that most cooling air entering a brake disc originates from the backside of the discs, especially when brake ducts are utilized. A comparison between an OEM pillar vane disc, an OEM dual-cast disc (technically a two-piece disc), and the AP Racing J Hook disc highlights the differences. The AP Racing disc provides a clear and unobstructed path for cooling air to enter and flow through the disc, whereas the OEM discs feature narrower inlet ports and potential obstructions that hinder the flow. As a result, the AP Racing disc maintains significantly lower temperatures, reducing the likelihood of cracking and wear.

Exclusive AP Racing J Hook Slot Pattern

• When modifications such as slots or holes are introduced to a brake disc, they can impact heat transfer. These modifications create cool spots around the slots or holes as the disc heats up, which is less than ideal. Ideally, heat should be evenly distributed across the disc to facilitate effective cooling by airflow and radiating away from the disc. The presence of cool spots can lead to areas of stress concentration and increase the likelihood of disc cracking. Furthermore, cool spots cause uneven distortion of the disc’s face, resulting in uneven pad deposits, vibrations, and judder.
• OEM discs address this issue by leaving the disc face blank, avoiding the formation of cool spots. While this reduces the risk of noise, vibration, and harshness (NVH), it also leads to a decrease in pad bite and a reduced tactile feel of the disc through the brake pedal. On the other hand, many competitive aftermarket discs feature straight slots, which tend to create cool spots across the disc face between the slots.
• Extensive research and development testing conducted by AP Racing has resulted in the development of the J Hook design. This design creates a consistent pathway of evenly distorted material on the disc face. The hooks are strategically spaced around the disc’s circumference and from the inside edge (where the hat attaches) to the outer edge, with a slight overlap to promote even heat distribution and distortion. In addition to reducing the risk of cracking, the even heating of the disc promotes the formation of a uniform transfer layer of pad material during the bedding-in process.

Complex Metallurgy Developed Through 50+ Years of Experience

• Boasting a rich legacy of over 50 years in brake component design, AP Racing has an outstanding track record that speaks to their expertise and reliability. Their components have been utilized in cars that have triumphed in over 750 Formula 1 races, solidifying their reputation as a trusted industry leader. In fact, it’s noteworthy that during any given race weekend, AP J Hook discs can be found on 75% or more of the NASCAR Sprint Cup grid.
• Leveraging their vast experience and knowledge, AP Racing has developed a proprietary iron alloy renowned for its exceptional durability. This alloy is meticulously engineered to withstand the rigorous conditions it will encounter. Unlike OEM discs that prioritize cost-effectiveness and ease of production, AP Racing’s design objectives are fundamentally different. Their unwavering focus is on delivering uncompromising performance and reliability, ensuring that their products can endure demanding usage without compromise.

Caliper Brackets & Hardware

• The caliper brackets included in this kit undergo precision machining from heat-treated 6061 T6 billet aluminum, renowned for its exceptional strength and durability. To further enhance their resilience, the brackets undergo a rigorous hard anodizing process. The same high standards employed in professional racing are maintained, using aircraft-grade hardware that meets stringent quality requirements.
• An outstanding feature of these brackets is their thoughtfully designed cutaway feature. This design allows for precise fitting of various brake duct kits currently available in the market. The cutaway design ensures a precise and secure fit, facilitating efficient cooling and airflow to the brakes, a crucial aspect for achieving optimal performance on the track.

Brake Ducting

• The use of aftermarket brake ducts in conjunction with Essex’s Competition Brake Kits is not recommended. Based on extensive experience, Essex has encountered packaging limitations that make it exceedingly challenging to achieve effective airflow from the front of the car to the center of the brake discs. The narrow diameter of the duct hoses and limited space within the fender well often pose obstacles when attempting to install properly-sized hoses that can provide sufficient cooling. Additionally, many aftermarket systems direct cooling air to incorrect locations, resulting in uneven cooling and temperature variations across the disc surface. These temperature differentials can contribute to premature cracking.
• Moreover, the plates used to attach brake ducts at the wheel hub can inadvertently trap heat against the inner disc face, leading to an overall increase in system temperatures. Considering these factors, the use of aftermarket brake ducts is not recommended.
• If your vehicle is equipped with OEM brake ducts that channel air into the wheel well or features air deflectors within the wheel area, it is acceptable to retain them. However, if you have installed an Essex Designed AP Racing Competition Brake Kit and observe higher-than-expected temperatures during operation, it is advised to contact Essex to discuss potential solutions.
• It is crucial to avoid attaching any additional components between the caliper bracket and the suspension upright. Attaching ears or tabs from a brake duct system between the bracket and upright can misalign the caliper from its intended orientation, posing a significant risk of damage to the entire brake system or the vehicle. The bracket should be directly bolted to the upright as originally intended, without any objects sandwiched in between.

Spiegler Stainless Steel Brake Lines

• The Competition Kits are supplied with premium stainless steel brake lines, known for their outstanding quality. Spiegler lines surpass competing options with their comprehensive array of features, offering unmatched performance advantages.

Disc Burnishing / Bedding Service

• Neglecting proper preparation before taking your brake discs out on the track can lead to issues such as juddering, vibration, and cracking. However, conducting the necessary preparations at the circuit can be challenging, as it consumes valuable practice time and may pose hazards to other drivers in close proximity. Moreover, on-track preparations lack consistency due to external factors like changing weather conditions or traffic, which can impede the repeatability required for optimal bedding and consistent stopping and restarting.
• To address these concerns, Essex now offers a professional burnishing service accessible to all customers. Initially exclusive to their racing clientele, this service allows individuals to have select Competition Brake Kits pre-burnished at Essex’s facility. Drawing on years of experience servicing discs for elite teams, Essex’s skilled technicians employ an automated computer system and adhere to a stringent regimen based on feedback from top drivers and crews. This guarantees maximum efficiency from AP Racing disc brake sets.
• It is worth noting that the pads included in your kit will not be pre-burnished. In other words, the burnishing procedure for the discs does not have to be performed with the exact set of pads that come with your kit. Essex will perform the disc burnishing in the pad compound of your choice, ensuring the benefits of the procedure while using the provided pads in your kit.

Features

• Saves 25+ unsprung lbs. from nose of the car vs. OEM brakes, despite being considerably larger.
• Features AP Racing CP9668 Radi-CAL Pro5000R six piston calipers.
• 372x34mm, 72 vane AP Racing disc.
• Uses 25mm (1 inch) thick brake pads.
• Every component designed to resist the heat of extended track sessions.
• Pistons sized properly to allow for seamless integration with OEM master cylinder and ABS system.
• Designed to work with OEM rear brakes or the AP Racing By Essex Rear Brake Kit.

What’s In The Box

• One pair AP Racing CP9668 Radi-CAL Pro5000R six piston calipers.
• One pair 372x34mm AP Racing 72 vane J Hook racing discs, with fully floating 6061 hard anodized aluminum hats, and attachment hardware.
• One pair caliper mounting brackets and hardware.
• One pair Spiegler Stainless Steel Brake Lines with abrasion resistant coating.
• Detailed installation instructions.
• Brake pads are NOT included with this system.
  • Selecting the right racing brake pads is a highly subjective decision. While some manufacturers include a set of low-quality pads with their brake kits, Essex takes a different approach. Instead of including pads that may not meet your preferences, they have chosen to separate the cost of the pads from their system. This allows customers to have the freedom to choose the pads that best align with their specific needs and desires. When you purchase this kit, you have the opportunity to select one set of front pads at a significant discount compared to their retail price. This approach empowers you to make a personalized choice and ensures that you are investing in the brake pads that perfectly suit your requirements.
  • DS1.11 – The DS1.11 brake pad is recognized as a moderate option for endurance racing compounds, offering a lower mu (friction coefficient) than the 3-12. It requires more pedal pressure but provides drivers with decreasing torque as temperatures rise. Some drivers find that this offers better control with street tires, although it may not last as long due to less aggressive wear against the discs. Nonetheless, it offers impressive resistance to high temperatures, although not as much as the 3-12. The DS1.11 is mainly distinguished by its sensation and fade resistance, making it well-suited for this type of racing.
  • DS2500 – When it comes to the track, dedicated race pads generally offer better performance. However, the DS2500 is an exceptional hybrid street/track pad that provides moderate bite and good resistance to fading. It also offers manageable levels of dusting and noise compared to other street pads. Some vehicles may produce some squealing when using this pad for its intended purpose. However, if your needs include high-speed driving, canyon runs, or occasional light track use with road tires, the DS2500 is unmatched in performance.
  • DS3.12 – Released in 2019, the DS3.12 is the latest addition to Ferodo’s impressive DS line. It was specifically designed to meet the high demands of modern sports cars, which have increased horsepower and aerodynamics, resulting in heavier curb weights and the need for stickier tires. Extensive testing has shown that the DS3.12 offers an impressively consistent torque curve across a wider range of temperatures compared to other pad compounds on the market. This means that each time you apply your brakes on turns or tracks, the performance remains consistent regardless of how hot they get. The DS3.12 also exhibits higher mu properties, requiring less pressure on the pedals for frequent braking, thus maintaining performance without fading even in hotter temperatures. This revolutionary compound sets itself apart not only from related products but also has the potential to become the gold standard once testing is completed.
  • DSUNO – For customers who appreciate the effectiveness of the DS1.11 brake pads but desire increased stopping power, the DSUNO pads are worth considering. While this compound may not offer as much longevity compared to the DS1.11, its peak friction coefficient (mu) is greater once it reaches the optimal operating temperature on the track.
• Pad Tension Clips (frequently referred to as anti-rattle clips) are NOT included with these Competition Kits, but they do offer them as an option if you’re concerned about NVH.
  • The AP Racing calipers in this system offer a notable advantage: they are designed to accommodate pads from various manufacturers. Each pad manufacturer has their own specifications, resulting in slight differences in pad dimensions. Consequently, pads from different manufacturers or batches may not fit the calipers in the exact same manner. Some pads may fit snugly, while others may have more movement and produce noise. To address this issue, Essex has developed the Essex Designed Pad Tension Kit. This kit is specifically designed to significantly reduce pad movement inside the caliper and eliminate associated noise. It’s important to note that each caliper requires one Pad Tension Kit (two kits per vehicle).

Applications

• 2023+ Nissan Z – RZ34
  • Application Type – Track

About AP Racing / Essex

In 1981, Michael Gue relocated to Essex, Connecticut, and established a business called “Essex Racing” to cater to the demand for British road racing cars and car parts in the United States. Having previously worked with similar materials in England, this experience likely influenced his decision to move countries and pursue business opportunities in America. Essex Racing quickly gained a loyal fanbase and became a trusted source for racing products.

In 1983, Essex Racing relocated to Atlanta, Georgia, seeking a warmer climate. The company continued to thrive as an importer of Van Diemen and Tiga formula and sports racing cars. Essex Racing actively participated in SCCA (Sports Car Club of America) and IMSA (International Motor Sports Association) road races, achieving success in both professional and amateur competitions throughout North America.

The growing interest in Essex’s racing vehicles led to an increased demand for related spare parts. To meet this demand, Essex Parts Services was established in 1992 as a dedicated business for selling these components. Over the next decade, Essex Parts Services became one of the leading distributors of racecar and stock car accessories in the United States.

In 1999, Michael Gue departed from the business, and Richard Martin and Ken Gordon took over Essex Parts Services. The company continued its success, leading to its relocation to Charlotte, North Carolina, in 2004 to better serve its substantial stock car clientele.

Throughout its history, Essex has remained attentive to its clients’ needs and has evolved accordingly. While the product range has significantly changed over the past 35 years, the company’s core principles have remained unchanged. Today, Essex stands as a prominent supplier of top-quality parts and services for road race, stock car, and high-performance street drivers across North America.