AP Racing by Essex Competition Endurance Brake Kit (Front CP8350/325mm)- Subaru BRZ, Scion FR-S & Toyota GT86/GR86 2013+

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.