As light and nimble as the Fiesta ST may be, it’s still known to cook the brakes when subjected to track days. And we’re going to be on track in just a few weeks so to ensure our time spent chasing Josh’s M3 is as fun as possible, we opted to proactively address potential braking issues now with a thorough brake upgrade. Rather than spend big bucks on a big brake kit, I opted for a more cost effective solution: increase cooling and swap to pads that can take more heat.
Starting with the front, new backing plates for the rotors were sourced from CM Buildz. These new backing plates include a built in duct that allows us to pipe fresh air from the front of the car directly to the rotors. We used a plastic 3″ to 2″ reducer and 2″ hose to route fresh air to the new backing plates. See our install video below (it’ll be up shortly so just subscribe to the RFD YouTube channel in the meantime). This setup has been proven to reduce brake rotor temperatures by 60 degrees on an autocross course. We suspect the margin will be significantly higher on a road course and if all goes well, this means we’ll be able to stay within the operating temperatures of our new brake pads.
So on to the brake pads. We replaced the stockers with Carbotech XP8’s, which are mild enough for street use but intended for the track. Read: mild enough for the street. This means we’ll expect some increased brake dust and noise between stop lights – likely something between a 3 AM cat fight and a wild pig in heat.
After securely mounting the caliper back in place with our new Carbotech pads, we removed the rubber brake lines and replaced them with stainless steel lines from StopTech. The primary reason for this modification is to keep a consistent brake pedal feel. Rubber can expand or even burst (more common with older vehicles) and stainless lines are cheap insurance.
To finish it off, we cracked the bleeder screw and flushed the original brake fluid with high temperature ATE Type 200. If not for the pads, the brake fluid may be the most critical piece of our puzzle. When pressing the brake pedal, hydraulic fluid is forced through skinny metal and rubber lines, which in turn compress the pads to the rotors by pushing small cylinders in the brake calipers against the pads. Unbelievable amount of heat is transferred from the rotors to the pads to the calipers and to the fluid in the process. If this fluid gets hot enough it can boil. When that happens the fluid can no longer be compressed and the brake pedal goes to the floor. Now you’re in no-man’s land speeding in to the sand traps, or worse. Not a great ending to a track day.
With the front buttoned up, we moved to the rear. We didn’t route any additional cooling but we did install High Carbon rotors. But honestly, this was more to have pads bedded-in exclusively to one set of rotors more so than anything else. You can probably skip this.
|CM Buildz rotor shields||$125|
|Carbotech XP8 pads||$360|
|High Carbon rear rotors||$80|
|Stoptech Stainless brake lines||$100|
|ATE Type 200 brake fluid||$15|
All said and done, this setup cost less than $750 and should provide plenty of bite under the extreme track conditions. The true test comes in May when we lap the brand new Dominion Raceway with SCCA’s Track Night in America.