Project FR-S: Installing a Big Brake Kit

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Update by Staff Writer to the Scion FR-S project car
May 15, 2020

Story and Photography by Wayne Presley 

In our quest to transform our Scion FR-S from a Copart salvage auction purchase into the ultimate weekend track toy, we’ve upgraded the suspension, tires and power, adding 80 extra wheel horsepower thanks to the BorgWarner turbo that we covered last issue.

But there was one big item left on the to-do list: brakes.

Did our FR-S really need them? We’ll put it this way: The factory FR-S brakes are considered perfectly adequate for track work at stock power levels, provided the pads and brake fluid are switched out for ones that can better handle elevated temperatures. Choose pads carefully and keep an eye on them, the theory goes, and the original brakes will work fine on track.

Although we could have squeezed a few sessions out of our stock brakes without issue, we’d rather not cut it so close. After all, our home tracks–Road Atlanta, Daytona, Sebring and Roebling Road–are relatively fast. On top of that, we’d already upped the horsepower by 50%, so we figured it was prudent to install brakes more suited for track work.

The big advantages of dedicated track brakes? Less weight, the ability to handle more heat, and the move to a standard pad shape. About that last one on the list: These AP calipers use a pad shape that’s common in motorsports, meaning we can now use a wide variety of available compounds at competitive prices. These pads are generally thicker, too. Over the long run, our math says, we’ll spend less on consumables.

Essex Parts Services, which imports and builds big-brake kits around premium AP Racing calipers, sells sprint and endurance brake kits for the FR-S and BRZ chassis: 299mm rotors for the sprint kit and 325mm discs for the endurance package. Since we won’t be endurance racing, we chose the sprint kit to save some weight and make sure everything would fit inside our 17-inch Mach V Motorsports wheels.

The setup features aluminum four-piston calipers as well as rotors that measure a whopping 32mm thick–meaning more cooling vane area and thermal mass than the stock pieces. Essex’s FR-S/BRZ front brake kit retails for $2099, and we measured a 9.6-pound weight savings per corner.

Once the kit landed, we could take a closer look. The kit revolves around–literally–a pair of AP Racing 8350 four-piston calipers.

What’s the difference between these and some of the more budget-oriented options? Instead of paint or powder coating, these are finished with hard anodizing, creating a surface that won’t flake off or dramatically change color over time.

Powder coating, on the other hand, can flake off in high heat, and those flakes have to land somewhere. If they land on the pistons, they can score seals, especially when the pistons are retracted during pad swaps. The result? Leaks, possibly.

These calipers also feature stainless-steel pistons for durability and low thermal conductivity, and behind those pistons are anti-knockback springs. What’s knockback? It’s the slight retreat of the piston into the caliper, and it can require a pump of the pedal before the pistons are pressed up against the pads. We’d rather not worry about knockback when facing a 65-mph corner at the end of a 125-mph straight.

The kit also includes anodized billet aluminum caliper brackets, stainless-steel brake hoses and thread locker for every fastener involved. The brackets fit like a glove, and the instructions are top tier. It took us less than 2 hours to install everything, and that’s including breaks for photography and weighing.

Once we’d swapped the front brakes, we moved on to the rears–just a pad change here, as the Essex Parts Services kit is designed to work with the stock rear brakes, stock master cylinder and factory ABS. Essex Parts Services recommended a pair of Ferodo pads.

After bleeding the system with AP Racing DOT 5.1 fluid, there was one more step: bedding in the pads. This process deposits a thin layer of pad material into the pores of the rotors, promoting better wear rates for both the rotor and pads.

How’s it done? By slowly bringing the rotors up to temperature via progressively harder, longer stops until the brakes can be smelled. Then an easy, 5-plus-minute drive cools everything evenly.

After that bedding, we reached our initial verdict. The brakes felt great at speed, delivering excellent modulation to go with the increased braking power.

Now we’re ready for our next mission: seeing how well this car actually performs on track.

Tired of Dripping Brake Fluid?

Hate that constant drip, drip, drip of brake fluid whenever you’re changing calipers or brake lines? Before you start, use a piece of scrap wood to depress the brake pedal an inch or two. Why? Because doing so covers the fluid compensating port in the master cylinder, blocking the reservoir from draining. You’ll have no drips and a much cleaner floor.




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