AP Racing 4-Piston Front Big Brake Sprint Kit Subaru BRZ / Scion FR-S / Toyota GT86
13.01.10005
For over 50 years, AP Racing has had one aim - to create winners on the race track.
The world of motorsport has changed out of all recognition since those early days and AP Racing have spearheaded every major development in brake and clutch technology.
The world of motorsport has changed out of all recognition since those early days and AP Racing have spearheaded every major development in brake and clutch technology.
Pricing:
$2,499.00
- Overview
- CP8350 Caliper Specs
- CP3862 Rotor Specs
- Summary
- Endurance vs. Sprint
- Details
- Shipping
- Reviews
Overview
The Toyobaru collaboration was one of the most anticipated enthusiast cars of the past decade. Teasers and tidbits trickled in for years, hinting at the potential of what was to come. The final product seems to have actually delivered on the hype, and a diverse range of sportscar fans are now flocking to these cars. Most enthusiasts view these cars as a fantastic platform to develop for track days and racing.
These cars were designed from the ground up as a pure sports car. Light weight, front engine, and rear drive all combine to offer a great driving experience on the street. On track with sticky tires, they're laying down lap times on par with what are supposed to be much faster cars. These cars were also designed with the aftermarket in mind. Many features of the car are rather basic to keep costs down, and the brakes are one of those areas. They're heavy, not particularly attractive, and leave a lot of performance on the table when track temperatures soar.
Not all brake systems are created equal. In fact, most “big brake kits” aren’t really suited towards heavy track use either. While they [usually] increase thermal capacity and may solve small fading issues, they generally aren’t optimized for hardcore track use. We set out to design a couple of brake packages that can take anything thrown at them...and then some.
These cars were designed from the ground up as a pure sports car. Light weight, front engine, and rear drive all combine to offer a great driving experience on the street. On track with sticky tires, they're laying down lap times on par with what are supposed to be much faster cars. These cars were also designed with the aftermarket in mind. Many features of the car are rather basic to keep costs down, and the brakes are one of those areas. They're heavy, not particularly attractive, and leave a lot of performance on the table when track temperatures soar.
Not all brake systems are created equal. In fact, most “big brake kits” aren’t really suited towards heavy track use either. While they [usually] increase thermal capacity and may solve small fading issues, they generally aren’t optimized for hardcore track use. We set out to design a couple of brake packages that can take anything thrown at them...and then some.
CP8350 Caliper Specs
20mm Thick, Inexpensive Brake Pads
Race pads aren’t cheap, and you burn through them quickly if you spend any amount of time on track. One of the great things about our Sprint and Endurance systems are the huge range of pad choice. The AP Racing CP8350 calipers in these systems use a pad shape that is available in just about every pad compound under the sun from all of the major manufacturers (Essex alone sells close to 20!). That means you’ll never end up in a pinch for a track weekend without pads. The average set of race pads for the front OEM BRZ calipers typically range from $200-$250, while the average set for the AP Racing CP8350 costs $175. How many sets of brake pads do you go through in a season? Some people find that they could pay off their brake system in a short period of time on pad savings alone.
Pad Comparison: Sprint, Endurance, and USDM OEM BRZ
Above are some photos that show the differences between the Sprint, Endurance, and FR-S / BRZ OEM brake pad shapes.
On the left is the pad used with our Sprint system. The particular Ferodo pad shown has a radial depth (height of the friction puck) of 41mm, although a depth of up to 43mm is useable with the Sprint system.
The pad in the center is a 50mm radial depth Ferodo pad, which can be used with our Endurance system. This is possible because the discs used in the Endurance system have a greater radial depth (taller disc face).
The pad on the right is the USDM OEM front BRZ pad.
You can see in the pictures that the pad faces of the Endurance and OEM pads have almost identical surface area, while the Sprint pads are slightly narrower. Many people mistakenly put too much emphasis on pad surface area. While surface area is an important factor in overall system design, the bigger news is pad volume.
Volume is the length x width x thickness of the pad, and determines how large of a heat sink the pad is. The friction puck (the material attached to the backing plate) on the Sprint and Endurance pads is roughly 15mm thick, while the puck on the OEM pads is roughly 10mm thick. That extra 5mm of thickness provides a huge pad volume increase, which is one of the factors that provides additional thermal capacity in the brake system. Think of the pad as a barrier between the brake disc and the caliper pistons. All else held equal, a thicker pad provides more material for heat to spread into and dissipate. The thicker pad will do a better job of insulating the pistons from disc heat (less chance of fade-related issues), and will also wear longer (less frequent pad replacements and lower running costs).
There are people out there who will tell you that aluminum pistons are great for track calipers. They will tell you that the expansion rates of the pistons and caliper body need to be the same when heated. This argument is completely invalid and unproven. Those same people tend to get upset when you point out the fact that every serious race caliper, from every serious race caliper manufacturer on the planet uses either stainless or titanium pistons, period. There is a reason for this: they work better!
Stainless steel pistons are far superior to aluminum pistons in creating a thermal barrier. They are much better at keeping heat out of your brake fluid and preventing a soft pedal from fluid fade on the track. This has been proven over and over again at all levels of motorsport. Don’t fight it, just accept it.
While the most aftermarket calipers uses a pressed aluminum piston, the CP8350 uses an expensive machined stainless steel piston. As discussed above, this is to slow and repel the influx of heat into the brake fluid.
Not only are the pistons stainless steel, they are fitted with anti-knockback springs. Springs in pistons you ask? Yes, springs. If you’ve ever gone through a series of S turns and then had your pedal drop when going into the following brake zone, you have experienced knockback. To say it is disconcerting is an understatement. You’ll often see pro drivers ‘pre-tap’ their brakes lightly when approaching a brake zone. They are fighting knockback.
Knockback is a phenomenon that is common with fixed calipers. Knockback occurs when your car’s wheel, hub, and bearings deflect during cornering, allowing your brake disc to move out of sync with your caliper and brake pads. The caliper is less prone to movement because it is attached to the more rigid upright. As the brake disc deflects, it actually pushes the pads away from each other, forcing the caliper pistons back into their bores. The piston seals don’t have enough tension in them to return the pistons to their original location. That means there is slack in the system that needs to be taken up. When you press the brake pedal, it will continue to drop until that slack is taken up.
Anti-knockback springs help alleviate this situation by putting some tension on the back side of the pistons. When the disc deflects and pushes the pistons, the springs push the pistons back into their proper location, reducing slack in the system. That means less pedal drop and far fewer pucker-factor moments when going into heavy brake zones.
Since the springs are only 4 lbs., and the seals in the calipers are specially designed to minimize brake drag, you won't see any negative impact on pad or disc wear.
Pictured above is a set of calipers we pulled from a car we were testing (Lancer Evo). We saw that the right hand caliper had a bent crossover pipe. Most likely it was bent when a wheel was being installed. Or, it could have been hit by a piece of track debris. Regardless of how it happened, this is precisely the type of damage the CP8350 was designed to prevent.
On the CP8350 the bleed screws and crossover pipe are hidden in little coves that protect them from contact. If you frequently pull your wheels on and off your car, you probably know how easy it is to bump your caliper with then inner barrel of the wheel. How easy would it be to ruin your weekend if you happened to knock off a bleed screw and kill your caliper? The integrated protection on the CP8350 will prevent anxiety the next time your friend is putting your wheel back on and you hear that dreaded ‘clunk.’
Also, there’s no need to worry about access to the bleed screws. Fitting a box end wrench on the bleed screw when bleeding isn’t an issue.
Most aftermarket calipers are designed for year round road use and as such come with a bellows style external dust seal. “So?” You ask. Well, we’ve seen them burn up in a single 20 minute session, and all they do is make a big mess. They usually look something like the above pics before and after track use.
Additionally, the OEM caliper seals aren’t designed to handle repeated trips to several hundred degrees without becoming brittle and leaking, etc. On the other hand, the CP8350 caliper has the exact same AP Racing high temperature seals used in NASCAR Sprint Cup, ALMS, DTM, etc. They are designed to operate at extreme temperatures without leaking, and require less frequent replacement and servicing. You won’t see a ragged mess here.
After the countless times you’ve changed your brake pads, you’re probably never too excited when it comes time to do so. Changing pads will no longer be a chore with the CP8350. No more pulling your OEM caliper off every time you want to swap apds. AP’s bridge bolt pops out easily with a 5mm hex wrench and a 7mm socket. It will take you longer to pull off the wheel than it will to change pads. Less time futzing around in the paddock, and more time driving= fun.
Pistons Sized Specifically for the BRZ / FR-S / GT86
The piston sizes for our system were specifically chosen for the FT86 platform, and have very little impact on the front to rear brake bias. That means our front system can be bolted to an otherwise stock brake system with no ill-effects, negative impact on ABS, etc. The vehicles stock master cylinder can remain, as can the OEM rear brake system.
Compact, Ultra-lightweight Package
Our brake system follows a simple philosophy: Anything larger than necessary to get the job done is simply dead weight to drag around.
If you’re worried about the loss of stiffness due to mass reduction, don’t. AP’s CP8350 is an extremely stiff, forged design, and the pedal feels rock hard on the FT86.
With pads and bracket, it weighs several pounds less than the OEM calipers! That’s less unsprung weight per corner to drag around. For the competitive individual, weight savings often becomes the holy grail of modifications. A lighter car means greater acceleration, superior handling, and less mass to bring to a halt. On a relatively low-powered car such as the FT86, this becomes even more important. At some point reducing weight becomes extremely expensive on a dollar per pound basis. When viewed in this manner, our system becomes an even greater bargain.
Most aftermarket calipers come in a painted finish, whether they are red, black, or gold. The painted finish is for corrosion resistance and appearance.
Unfortunately, for all of the compliments pretty gold calipers generate, there is an associated price if you drive the car in a track environment. That price is the chipping, flaking, fading, color shift, and general decimation of the finish in a fairly short period of time. We’ve seen painted OEM and aftermarket calipers go from the as-delivered color to a nasty shade of brown in as little as one weekend. While this is typically worn as a badge of honor among our more hardcore customers, let’s face it…they still look terrible. More importantly though, all of those bits of paint end up in places they’re not supposed to, which I’ll get to in a minute.
Why does this happen? Heat. Paint and powder coat cannot adequately handle the temperatures that calipers hit when run on a track. Powder coat also has some notorious issues with shrinkage. The powder coat layer expands and grows when the caliper is heated. When it cools however, the powder coat doesn’t necessarily shrink in step with the caliper body itself. What’s left is a loose shell of finish hanging limply on the caliper body. That shell then cracks and falls to pieces.
Paint can also have similar issues depending on how it is applied. If you were to line up a few aftermarket calipers from the same manufacturer, you would likely see that the painted finish on each of those calipers is slightly different. Some have a thicker coat, some thinner, slightly different shades of red, etc. Painting is to some extent an art form, and must be performed in a tightly controlled environment. If it isn’t, you’re always going to see variation. A thick coat makes the part look soft around the edges, and is prone to cracking off in the same manner as the powder coat described above, leaving the underlying finish exposed. A part without enough paint will look uneven, and will not protect the underlying aluminum particularly well either.
In addition to problems with cracking, flaking, and uneven application, paint and powder coat also experience extreme color shift when heated. Red becomes maroon or black, gold becomes brown, and black just gets uglier.
Now let’s take a look at some real racing calipers.
The caliper we're using in our Essex Competition Brake Systems is the AP Racing CP8350. This caliper was designed to be ultra-lightweight, stiff, and durable under all track conditions. The finish we chose is a hard anodizing. Hard anodizing is the business under track conditions.
When raw aluminum reacts with the oxygen in the air, a hard surface film develops on aluminum which prevents further degradation. The process is called oxidation, and you can think of it like rust. The anodizing process leverages this natural phenomenon, and takes it a step further to produce an extremely hard protective layer of aluminum oxide on the aluminum. It does so by running an electrical current through an acid bath, and dying it to the desired color. If you want to know more, Google it.
The result is a finish that is far more appropriate for racetrack use. Anodizing creates a uniform surface that is much more abrasion resistant than paint or powder coat. That means if you ding an anodized caliper with a box wrench when bleeding it, a big chunk of the finish isn’t going to chip off into your hand. While anodized calipers will still exhibit minor color shift, it will take a lot more heat to get them to change, and they won’t change as dramatically. They will go from semi-ugly grey, to a semi-ugly grey-brown (see below). In short, they’ll look like the race calipers they are. More importantly though, you aren’t going to have bits of anodizing sticking to the sides of your pistons.
Please do keep in mind however, that every yellow AP logo is hand painted on the caliper. It will degrade over time, particularly if you slop brake fluid all over it. Our customers asked us for something with at least a little visual punch and some brand recognition, so we had to offer them this token. Also keep in mind that an anodized finish is not designed to be driven through road salt.
Okay, so we’ve established that paint and powder coat are not ideal choices for calipers that will be thrashed at several hundred degrees on the track. While the finish is the most blatant feature that people key in on, it’s actually not nearly as important as some of the other features in the caliper that allow it to operate efficiently at track temperatures.
Race pads aren’t cheap, and you burn through them quickly if you spend any amount of time on track. One of the great things about our Sprint and Endurance systems are the huge range of pad choice. The AP Racing CP8350 calipers in these systems use a pad shape that is available in just about every pad compound under the sun from all of the major manufacturers (Essex alone sells close to 20!). That means you’ll never end up in a pinch for a track weekend without pads. The average set of race pads for the front OEM BRZ calipers typically range from $200-$250, while the average set for the AP Racing CP8350 costs $175. How many sets of brake pads do you go through in a season? Some people find that they could pay off their brake system in a short period of time on pad savings alone.
Pad Comparison: Sprint, Endurance, and USDM OEM BRZ
Above are some photos that show the differences between the Sprint, Endurance, and FR-S / BRZ OEM brake pad shapes.
On the left is the pad used with our Sprint system. The particular Ferodo pad shown has a radial depth (height of the friction puck) of 41mm, although a depth of up to 43mm is useable with the Sprint system.
The pad in the center is a 50mm radial depth Ferodo pad, which can be used with our Endurance system. This is possible because the discs used in the Endurance system have a greater radial depth (taller disc face).
The pad on the right is the USDM OEM front BRZ pad.
You can see in the pictures that the pad faces of the Endurance and OEM pads have almost identical surface area, while the Sprint pads are slightly narrower. Many people mistakenly put too much emphasis on pad surface area. While surface area is an important factor in overall system design, the bigger news is pad volume.
Volume is the length x width x thickness of the pad, and determines how large of a heat sink the pad is. The friction puck (the material attached to the backing plate) on the Sprint and Endurance pads is roughly 15mm thick, while the puck on the OEM pads is roughly 10mm thick. That extra 5mm of thickness provides a huge pad volume increase, which is one of the factors that provides additional thermal capacity in the brake system. Think of the pad as a barrier between the brake disc and the caliper pistons. All else held equal, a thicker pad provides more material for heat to spread into and dissipate. The thicker pad will do a better job of insulating the pistons from disc heat (less chance of fade-related issues), and will also wear longer (less frequent pad replacements and lower running costs).
There are people out there who will tell you that aluminum pistons are great for track calipers. They will tell you that the expansion rates of the pistons and caliper body need to be the same when heated. This argument is completely invalid and unproven. Those same people tend to get upset when you point out the fact that every serious race caliper, from every serious race caliper manufacturer on the planet uses either stainless or titanium pistons, period. There is a reason for this: they work better!
Stainless steel pistons are far superior to aluminum pistons in creating a thermal barrier. They are much better at keeping heat out of your brake fluid and preventing a soft pedal from fluid fade on the track. This has been proven over and over again at all levels of motorsport. Don’t fight it, just accept it.
While the most aftermarket calipers uses a pressed aluminum piston, the CP8350 uses an expensive machined stainless steel piston. As discussed above, this is to slow and repel the influx of heat into the brake fluid.
Not only are the pistons stainless steel, they are fitted with anti-knockback springs. Springs in pistons you ask? Yes, springs. If you’ve ever gone through a series of S turns and then had your pedal drop when going into the following brake zone, you have experienced knockback. To say it is disconcerting is an understatement. You’ll often see pro drivers ‘pre-tap’ their brakes lightly when approaching a brake zone. They are fighting knockback.
Knockback is a phenomenon that is common with fixed calipers. Knockback occurs when your car’s wheel, hub, and bearings deflect during cornering, allowing your brake disc to move out of sync with your caliper and brake pads. The caliper is less prone to movement because it is attached to the more rigid upright. As the brake disc deflects, it actually pushes the pads away from each other, forcing the caliper pistons back into their bores. The piston seals don’t have enough tension in them to return the pistons to their original location. That means there is slack in the system that needs to be taken up. When you press the brake pedal, it will continue to drop until that slack is taken up.
Anti-knockback springs help alleviate this situation by putting some tension on the back side of the pistons. When the disc deflects and pushes the pistons, the springs push the pistons back into their proper location, reducing slack in the system. That means less pedal drop and far fewer pucker-factor moments when going into heavy brake zones.
Since the springs are only 4 lbs., and the seals in the calipers are specially designed to minimize brake drag, you won't see any negative impact on pad or disc wear.
Pictured above is a set of calipers we pulled from a car we were testing (Lancer Evo). We saw that the right hand caliper had a bent crossover pipe. Most likely it was bent when a wheel was being installed. Or, it could have been hit by a piece of track debris. Regardless of how it happened, this is precisely the type of damage the CP8350 was designed to prevent.
On the CP8350 the bleed screws and crossover pipe are hidden in little coves that protect them from contact. If you frequently pull your wheels on and off your car, you probably know how easy it is to bump your caliper with then inner barrel of the wheel. How easy would it be to ruin your weekend if you happened to knock off a bleed screw and kill your caliper? The integrated protection on the CP8350 will prevent anxiety the next time your friend is putting your wheel back on and you hear that dreaded ‘clunk.’
Also, there’s no need to worry about access to the bleed screws. Fitting a box end wrench on the bleed screw when bleeding isn’t an issue.
Most aftermarket calipers are designed for year round road use and as such come with a bellows style external dust seal. “So?” You ask. Well, we’ve seen them burn up in a single 20 minute session, and all they do is make a big mess. They usually look something like the above pics before and after track use.
Additionally, the OEM caliper seals aren’t designed to handle repeated trips to several hundred degrees without becoming brittle and leaking, etc. On the other hand, the CP8350 caliper has the exact same AP Racing high temperature seals used in NASCAR Sprint Cup, ALMS, DTM, etc. They are designed to operate at extreme temperatures without leaking, and require less frequent replacement and servicing. You won’t see a ragged mess here.
After the countless times you’ve changed your brake pads, you’re probably never too excited when it comes time to do so. Changing pads will no longer be a chore with the CP8350. No more pulling your OEM caliper off every time you want to swap apds. AP’s bridge bolt pops out easily with a 5mm hex wrench and a 7mm socket. It will take you longer to pull off the wheel than it will to change pads. Less time futzing around in the paddock, and more time driving= fun.
Pistons Sized Specifically for the BRZ / FR-S / GT86
The piston sizes for our system were specifically chosen for the FT86 platform, and have very little impact on the front to rear brake bias. That means our front system can be bolted to an otherwise stock brake system with no ill-effects, negative impact on ABS, etc. The vehicles stock master cylinder can remain, as can the OEM rear brake system.
Compact, Ultra-lightweight Package
Our brake system follows a simple philosophy: Anything larger than necessary to get the job done is simply dead weight to drag around.
If you’re worried about the loss of stiffness due to mass reduction, don’t. AP’s CP8350 is an extremely stiff, forged design, and the pedal feels rock hard on the FT86.
With pads and bracket, it weighs several pounds less than the OEM calipers! That’s less unsprung weight per corner to drag around. For the competitive individual, weight savings often becomes the holy grail of modifications. A lighter car means greater acceleration, superior handling, and less mass to bring to a halt. On a relatively low-powered car such as the FT86, this becomes even more important. At some point reducing weight becomes extremely expensive on a dollar per pound basis. When viewed in this manner, our system becomes an even greater bargain.
Most aftermarket calipers come in a painted finish, whether they are red, black, or gold. The painted finish is for corrosion resistance and appearance.
Unfortunately, for all of the compliments pretty gold calipers generate, there is an associated price if you drive the car in a track environment. That price is the chipping, flaking, fading, color shift, and general decimation of the finish in a fairly short period of time. We’ve seen painted OEM and aftermarket calipers go from the as-delivered color to a nasty shade of brown in as little as one weekend. While this is typically worn as a badge of honor among our more hardcore customers, let’s face it…they still look terrible. More importantly though, all of those bits of paint end up in places they’re not supposed to, which I’ll get to in a minute.
Why does this happen? Heat. Paint and powder coat cannot adequately handle the temperatures that calipers hit when run on a track. Powder coat also has some notorious issues with shrinkage. The powder coat layer expands and grows when the caliper is heated. When it cools however, the powder coat doesn’t necessarily shrink in step with the caliper body itself. What’s left is a loose shell of finish hanging limply on the caliper body. That shell then cracks and falls to pieces.
Paint can also have similar issues depending on how it is applied. If you were to line up a few aftermarket calipers from the same manufacturer, you would likely see that the painted finish on each of those calipers is slightly different. Some have a thicker coat, some thinner, slightly different shades of red, etc. Painting is to some extent an art form, and must be performed in a tightly controlled environment. If it isn’t, you’re always going to see variation. A thick coat makes the part look soft around the edges, and is prone to cracking off in the same manner as the powder coat described above, leaving the underlying finish exposed. A part without enough paint will look uneven, and will not protect the underlying aluminum particularly well either.
In addition to problems with cracking, flaking, and uneven application, paint and powder coat also experience extreme color shift when heated. Red becomes maroon or black, gold becomes brown, and black just gets uglier.
Now let’s take a look at some real racing calipers.
The caliper we're using in our Essex Competition Brake Systems is the AP Racing CP8350. This caliper was designed to be ultra-lightweight, stiff, and durable under all track conditions. The finish we chose is a hard anodizing. Hard anodizing is the business under track conditions.
When raw aluminum reacts with the oxygen in the air, a hard surface film develops on aluminum which prevents further degradation. The process is called oxidation, and you can think of it like rust. The anodizing process leverages this natural phenomenon, and takes it a step further to produce an extremely hard protective layer of aluminum oxide on the aluminum. It does so by running an electrical current through an acid bath, and dying it to the desired color. If you want to know more, Google it.
The result is a finish that is far more appropriate for racetrack use. Anodizing creates a uniform surface that is much more abrasion resistant than paint or powder coat. That means if you ding an anodized caliper with a box wrench when bleeding it, a big chunk of the finish isn’t going to chip off into your hand. While anodized calipers will still exhibit minor color shift, it will take a lot more heat to get them to change, and they won’t change as dramatically. They will go from semi-ugly grey, to a semi-ugly grey-brown (see below). In short, they’ll look like the race calipers they are. More importantly though, you aren’t going to have bits of anodizing sticking to the sides of your pistons.
Please do keep in mind however, that every yellow AP logo is hand painted on the caliper. It will degrade over time, particularly if you slop brake fluid all over it. Our customers asked us for something with at least a little visual punch and some brand recognition, so we had to offer them this token. Also keep in mind that an anodized finish is not designed to be driven through road salt.
Okay, so we’ve established that paint and powder coat are not ideal choices for calipers that will be thrashed at several hundred degrees on the track. While the finish is the most blatant feature that people key in on, it’s actually not nearly as important as some of the other features in the caliper that allow it to operate efficiently at track temperatures.
CP3862 Rotor Specs
Width and Thermal Mass
One of the primary goals with a brake disc is to put the mass of the disc where it counts. The area of the disc that is swept by the pads is where the most heat will enter the disc, and that area's design is critical in determining how heat will flow through and out of the disc. With the OEM discs, much of the disc's mass is located in the hat portion, near the hub of the car. Having a mass of hot iron in that area isn't particularly beneficial to lowering brake temps, and also adds wear and tear on your wheel bearings, etc. With an aftermarket two-piece disc, almost all of the disc's mass is located in the swept region, which is where it can absorb and radiate heat through the disc's vanes. Therefore, two discs of roughly the same overall dimensions on paper can have tremendously different capabilities to absorb and transfer brake energy into heat.
The CP3862 is 299mm x 32mm. By using a relatively small diameter disc that is wider, we can gain the thermal mass we need without requiring large diameter wheels. We go from an OEM 24mm wide disc to a 32mm disc. We now have a beautiful wide air gap to flow a ton of air. We also maintain a lower moment of inertia. Essentially what that means is, a smaller diameter disc has its weight distributed more closely to the center axis around which it spins(hub), and is easier to accelerate than a larger diameter disc of equal mass.
Vane Design
The internal vane design on AP’s CP3862 is quite a bit different vs. the OEM discs. After extensive CFD and thermal stress analysis, AP designed the Heavy Duty J Hook with 60 curved vanes and a wide air gap to increase airspeed and heat transfer, while reducing deflection and remaining reasonably lightweight. The increased directional vane count on the J Hook Heavy Duty Disc amplifies air speed through the disc, reduces air recirculation between vents, and also increases convective heat transfer and heat distribution. In other words, both air and heat move more quickly and evenly through the disc, creating increased stability under the extreme loads of racetrack use. The disc is less prone to coning, distortion, and cracking than the OEM disc, while providing less brake fade, reduced judder, and a longer service life.
Weight
The weight difference between the AP Racing CP3862 and the OEM front disc is glaring. The CP3862 weighs in at svelte 12.2 lbs. with hat, while the OEM front disc is a portly 17 lbs., a difference of roughly 5 lbs. unsprung weight (a hat is not attached to the AP disc below, which adds roughly 1lb.)!
Two-piece Design with Aluminum Hat
For our Sprint Competition package, the discs are fix mounted/bolted to the aluminum hats. The bolted hat doesn't make any noise or rattle, and would therefore be the ideal choice if NVH is of any concern. It does not have any float however, and therefore wouldn't be quite as effective at reducing stress as the floating setup in our Endurance System. That said, we have many hundreds of our CP3862 discs on Late Model racecars using a bolted hat, and we never have any reported problems of stress-related cracking. These cars are 2800 lbs. and 500hp, and stand on their brakes every 7-9 seconds! Therefore, we certainly don't foresee any problems on the FT86.
The disc hats themselves are manufactured from 2024-T351 heat-treated billet aluminum, with a hard anodize coating for extra durability. This material was specifically chosen for its strength at high temperatures, as it will be in direct contact with the searing hot iron discs. The hats feature scallops on the underside, to allow for heat evacuation along the outer disc face once installed.
Exclusive AP Racing J Hook slot pattern
When you cut a slot or drill a hole in a disc you impact heat transfer. The area around the slot or hole acts as a cool spot when the disc heats up, which is not ideal. Ideally, heat is distributed uniformly around the disc so it can be hit with the cooling air that is pumping through the disc, radiate outwards away from the disc, etc. Cool spots create stress risers and increase the likelihood of the disc cracking. They also cause the face of the disc to distort unevenly, leading to uneven pad deposits, vibration, and judder.
The OEM discs avoid this problem by simply leaving the face blank. While the risk for NVH goes down, so does the pad bite and feel of the disc through the brake pedal.
During exhaustive R&D testing, AP's J Hook design was found to create a constant pathway of evenly distorted material on the face of the disc. The hooks are spaced out as evenly as possible both around the circumference of the disc, as well as from the inside edge (where the hat attaches) to outer edge, with a slight overlap to promote even heat distribution/distortion. In addition to reducing cracking, the even heating of the disc also helps provide an even transfer layer of pad material on the disc when you bed them in.
Additionally, the J Hook slot pattern produces a greater number of leading edges for the pads to bite into vs. a traditional curved slot pattern, and particularly a plain-faced disc. While this may lead to slightly more whirring or scraping noises from the discs when applying the brakes, the benefits of more even heat distribution, less propensity to crack, cleaner pad material transfer during bed-in, and more bite far outweigh the slight increase in NVH for the serious enthusiast.
Feature: Complex metallurgy developed through 50+ years of experience
AP Racing has been designing brake components for more than 50 years. They've had their components on cars that have won more than 600 grand prix's (Formula 1). On any given race weekend, AP J Hook discs can be found on 75% or more of the NASCAR Sprint Cup grid. AP has learned from these experiences, and have developed a proprietary iron alloy with extreme durability, designed specifically for what you intend to do with it (flog the hell out of it).
Reasonable replacement cost
Let's face it, no matter how good a brake disc is, it's still a consumable item. They're no different than brake pads or gasoline. You beat them up until they crack to pieces, then you throw them away. If replacement iron is too expensive, you're always driving in fear, waiting to shell out big bucks for a new set. Despite having the most expansive set of features on the market, the 299x32mm Heavy Duty J Hook's retail for a budget-friendly $158 each.
Going to the track is expensive! Event entrance fees, hotels, fuel, and tires all add up. While you obviously want the best product available, you can't afford to pay a small fortune for something you're just going to destroy. You can buy a set of cheap, heavy, OEM-style repalcement discs every so often, but you're much more likely to have heat-related brake issues, and you'll find yourself swapping them out much more frequently. When you do the math, the long-term value of the AP J Hook's is tough to beat. You'll enjoy all the benefits without breaking the bank, and you'll spend more time driving and less time wrenching.
Elite level teams choose AP Racing discs because they know the work has been done to provide the best available product at any price level. The AP Heavy Duty J Hook is a direct derivative of AP's vast racing experience. You can buy with confidence knowing that you're getting the best product available at any price point. A note of caution however: the J Hook design is often imitated, and there are a number of lesser quality imitations on market. Before purchasing, make sure you are getting an authentic AP Racing J Hook!
Caliper Brackets & Hardware
Caliper brackets for our kit are machined from heat-treated 6061 T6 billet aluminum, and hard anodized, ensuring strength and durability. All included socket head bolts are a high tensile strength steel. One of the nice features of our brackets is their cutaway design, which allows for the snug fitment of many currently available brake duct kits.
One of the primary goals with a brake disc is to put the mass of the disc where it counts. The area of the disc that is swept by the pads is where the most heat will enter the disc, and that area's design is critical in determining how heat will flow through and out of the disc. With the OEM discs, much of the disc's mass is located in the hat portion, near the hub of the car. Having a mass of hot iron in that area isn't particularly beneficial to lowering brake temps, and also adds wear and tear on your wheel bearings, etc. With an aftermarket two-piece disc, almost all of the disc's mass is located in the swept region, which is where it can absorb and radiate heat through the disc's vanes. Therefore, two discs of roughly the same overall dimensions on paper can have tremendously different capabilities to absorb and transfer brake energy into heat.
The CP3862 is 299mm x 32mm. By using a relatively small diameter disc that is wider, we can gain the thermal mass we need without requiring large diameter wheels. We go from an OEM 24mm wide disc to a 32mm disc. We now have a beautiful wide air gap to flow a ton of air. We also maintain a lower moment of inertia. Essentially what that means is, a smaller diameter disc has its weight distributed more closely to the center axis around which it spins(hub), and is easier to accelerate than a larger diameter disc of equal mass.
Vane Design
The internal vane design on AP’s CP3862 is quite a bit different vs. the OEM discs. After extensive CFD and thermal stress analysis, AP designed the Heavy Duty J Hook with 60 curved vanes and a wide air gap to increase airspeed and heat transfer, while reducing deflection and remaining reasonably lightweight. The increased directional vane count on the J Hook Heavy Duty Disc amplifies air speed through the disc, reduces air recirculation between vents, and also increases convective heat transfer and heat distribution. In other words, both air and heat move more quickly and evenly through the disc, creating increased stability under the extreme loads of racetrack use. The disc is less prone to coning, distortion, and cracking than the OEM disc, while providing less brake fade, reduced judder, and a longer service life.
Weight
The weight difference between the AP Racing CP3862 and the OEM front disc is glaring. The CP3862 weighs in at svelte 12.2 lbs. with hat, while the OEM front disc is a portly 17 lbs., a difference of roughly 5 lbs. unsprung weight (a hat is not attached to the AP disc below, which adds roughly 1lb.)!
Two-piece Design with Aluminum Hat
For our Sprint Competition package, the discs are fix mounted/bolted to the aluminum hats. The bolted hat doesn't make any noise or rattle, and would therefore be the ideal choice if NVH is of any concern. It does not have any float however, and therefore wouldn't be quite as effective at reducing stress as the floating setup in our Endurance System. That said, we have many hundreds of our CP3862 discs on Late Model racecars using a bolted hat, and we never have any reported problems of stress-related cracking. These cars are 2800 lbs. and 500hp, and stand on their brakes every 7-9 seconds! Therefore, we certainly don't foresee any problems on the FT86.
The disc hats themselves are manufactured from 2024-T351 heat-treated billet aluminum, with a hard anodize coating for extra durability. This material was specifically chosen for its strength at high temperatures, as it will be in direct contact with the searing hot iron discs. The hats feature scallops on the underside, to allow for heat evacuation along the outer disc face once installed.
Exclusive AP Racing J Hook slot pattern
When you cut a slot or drill a hole in a disc you impact heat transfer. The area around the slot or hole acts as a cool spot when the disc heats up, which is not ideal. Ideally, heat is distributed uniformly around the disc so it can be hit with the cooling air that is pumping through the disc, radiate outwards away from the disc, etc. Cool spots create stress risers and increase the likelihood of the disc cracking. They also cause the face of the disc to distort unevenly, leading to uneven pad deposits, vibration, and judder.
The OEM discs avoid this problem by simply leaving the face blank. While the risk for NVH goes down, so does the pad bite and feel of the disc through the brake pedal.
During exhaustive R&D testing, AP's J Hook design was found to create a constant pathway of evenly distorted material on the face of the disc. The hooks are spaced out as evenly as possible both around the circumference of the disc, as well as from the inside edge (where the hat attaches) to outer edge, with a slight overlap to promote even heat distribution/distortion. In addition to reducing cracking, the even heating of the disc also helps provide an even transfer layer of pad material on the disc when you bed them in.
Additionally, the J Hook slot pattern produces a greater number of leading edges for the pads to bite into vs. a traditional curved slot pattern, and particularly a plain-faced disc. While this may lead to slightly more whirring or scraping noises from the discs when applying the brakes, the benefits of more even heat distribution, less propensity to crack, cleaner pad material transfer during bed-in, and more bite far outweigh the slight increase in NVH for the serious enthusiast.
Feature: Complex metallurgy developed through 50+ years of experience
AP Racing has been designing brake components for more than 50 years. They've had their components on cars that have won more than 600 grand prix's (Formula 1). On any given race weekend, AP J Hook discs can be found on 75% or more of the NASCAR Sprint Cup grid. AP has learned from these experiences, and have developed a proprietary iron alloy with extreme durability, designed specifically for what you intend to do with it (flog the hell out of it).
Reasonable replacement cost
Let's face it, no matter how good a brake disc is, it's still a consumable item. They're no different than brake pads or gasoline. You beat them up until they crack to pieces, then you throw them away. If replacement iron is too expensive, you're always driving in fear, waiting to shell out big bucks for a new set. Despite having the most expansive set of features on the market, the 299x32mm Heavy Duty J Hook's retail for a budget-friendly $158 each.
Going to the track is expensive! Event entrance fees, hotels, fuel, and tires all add up. While you obviously want the best product available, you can't afford to pay a small fortune for something you're just going to destroy. You can buy a set of cheap, heavy, OEM-style repalcement discs every so often, but you're much more likely to have heat-related brake issues, and you'll find yourself swapping them out much more frequently. When you do the math, the long-term value of the AP J Hook's is tough to beat. You'll enjoy all the benefits without breaking the bank, and you'll spend more time driving and less time wrenching.
Elite level teams choose AP Racing discs because they know the work has been done to provide the best available product at any price level. The AP Heavy Duty J Hook is a direct derivative of AP's vast racing experience. You can buy with confidence knowing that you're getting the best product available at any price point. A note of caution however: the J Hook design is often imitated, and there are a number of lesser quality imitations on market. Before purchasing, make sure you are getting an authentic AP Racing J Hook!
Caliper Brackets & Hardware
Caliper brackets for our kit are machined from heat-treated 6061 T6 billet aluminum, and hard anodized, ensuring strength and durability. All included socket head bolts are a high tensile strength steel. One of the nice features of our brackets is their cutaway design, which allows for the snug fitment of many currently available brake duct kits.
Summary
Summary and Conclusion
Based on everything we’ve learned during development, we believe our system offers our customers the following advantages over the OEM BRZ / FR-S / GT86 brake system:
10 lbs. unsprung weight reduction from both front corners of the car. Twenty lbs. total are removed from the nose of the car, improving front to rear weight balance.
Incredible array of inexpensive race pad options at prices that are substantially lower per set than the OEM pad shape. The 20mm pads are 50% thicker than stock, providing far greater wear resistance and insulation for your calipers.
Extremely compact package for low moment of inertia, lowest possible weight, and superior wheel fitment
High airflow, heavy duty AP Racing J Hook brake discs that are substantially lighter than the OEM units, available at an extremely competitive replacement price ($158 each).
Disc metallurgy specifically designed to handle the temps typically seen on track offers a long service life, and low long-term running costs
Stainless steel pistons that keep heat out of your brake fluid to resist fluid fade during extended track sessions
Mitigation of pad knockback due to 4lb. anti-knockback springs in the calipers
Less chance of damaging bleed screws or crossover tubes when changing wheels due to built-in protection
Anodized caliper finish that is more resistant to wear and deterioration
Stainless steel caliper hardware for a long caliper service life under frequent pad change conditions
High temperature, low drag seals that will hold up to track temps better than OEM components= less rebuilding and longer service life
No dust boots to burn up and make a big mess
Simple pad change with one bolt
Lifetime professional caliper rebuilding support by Essex (at a fee)- pull off your calipers, send them to us, we clean, inspect, and rebuild them
AP Racing J Hook slot design that gives more pad bite/feel, and distributes heat evenly throughout the disc
Highest quality, Spiegler stainless steel brake line with clear sheath that reduces compliance over OEM rubber design.
Based on everything we’ve learned during development, we believe our system offers our customers the following advantages over the OEM BRZ / FR-S / GT86 brake system:
10 lbs. unsprung weight reduction from both front corners of the car. Twenty lbs. total are removed from the nose of the car, improving front to rear weight balance.
Incredible array of inexpensive race pad options at prices that are substantially lower per set than the OEM pad shape. The 20mm pads are 50% thicker than stock, providing far greater wear resistance and insulation for your calipers.
Extremely compact package for low moment of inertia, lowest possible weight, and superior wheel fitment
High airflow, heavy duty AP Racing J Hook brake discs that are substantially lighter than the OEM units, available at an extremely competitive replacement price ($158 each).
Disc metallurgy specifically designed to handle the temps typically seen on track offers a long service life, and low long-term running costs
Stainless steel pistons that keep heat out of your brake fluid to resist fluid fade during extended track sessions
Mitigation of pad knockback due to 4lb. anti-knockback springs in the calipers
Less chance of damaging bleed screws or crossover tubes when changing wheels due to built-in protection
Anodized caliper finish that is more resistant to wear and deterioration
Stainless steel caliper hardware for a long caliper service life under frequent pad change conditions
High temperature, low drag seals that will hold up to track temps better than OEM components= less rebuilding and longer service life
No dust boots to burn up and make a big mess
Simple pad change with one bolt
Lifetime professional caliper rebuilding support by Essex (at a fee)- pull off your calipers, send them to us, we clean, inspect, and rebuild them
AP Racing J Hook slot design that gives more pad bite/feel, and distributes heat evenly throughout the disc
Highest quality, Spiegler stainless steel brake line with clear sheath that reduces compliance over OEM rubber design.
Endurance vs. Sprint
ENDURANCE VS. SPRINT SYSTEM COMPARISON
Sprint system is roughly 10 lbs. lighter per corner than stock, while Endurance system is approximately 5 lbs. lighter per corner than stock
Endurance System comes with built-in provision for connecting brake ducts
Endurance system uses slightly larger disc, with a higher internal vane count
Aluminum hats on Endurance discs are floating, while hats on Sprint discs are bolted
Actual disc metallurgy the same for both kits, although spare discs for Sprint system are about $100 cheaper (each)...$200 less for the pair.
Slightly taller pads can be used on the Endurance package, giving greater pad volume and longer wear characteristics
Any pad that works in the Sprint System will also work in the Endurance package
Both kits will fit under certain 17" wheels, but neither will fit OEM wheels without a spacer. Wheel fitment templates available on our site.
Sprint system is roughly 10 lbs. lighter per corner than stock, while Endurance system is approximately 5 lbs. lighter per corner than stock
Endurance System comes with built-in provision for connecting brake ducts
Endurance system uses slightly larger disc, with a higher internal vane count
Aluminum hats on Endurance discs are floating, while hats on Sprint discs are bolted
Actual disc metallurgy the same for both kits, although spare discs for Sprint system are about $100 cheaper (each)...$200 less for the pair.
Slightly taller pads can be used on the Endurance package, giving greater pad volume and longer wear characteristics
Any pad that works in the Sprint System will also work in the Endurance package
Both kits will fit under certain 17" wheels, but neither will fit OEM wheels without a spacer. Wheel fitment templates available on our site.
Details
- 13.01.10005
- 13.01.10005
- AP Racing
- New
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