Project Porsche 987.2 Cayman S: Making Awesome Brakes More Awesome with Stoptech!

The 987.2 Cayman S has pretty decent brakes in stock condition.  It comes from the factory with Brembo 4 piston calipers with 318x28mm front rotors and 299x24mm rear rotors.  However, for our use, we want something with somewhat difficult to engineer specs.  We want a brake system that can be driven hard on the track with a car that has grippy tires and decent downforce, but the same car also has to be driven on the street without changing brake pads to a race compound pad. Thus the brakes have to have enough thermal capacity to keep the temperatures low enough for street pads to work.  We asked our friends at Stoptech to help us come up with a system that would work for this dual-purpose use.

For our front brakes, we needed a larger pad with more swept area for longer life with a less aggressive friction material.  To replace our 4-piston Brembo caliper we got a Stoptech STR-60 caliper.  The STR-60 Caliper uses a forged aluminum-alloy body that has all of the excess material as determined with FEA analysis, CNC machined away for less weight without sacrificing stiffness.  This post forging machining saves about 3/4 pound off Stoptechs standard caliper of the same size.  We were lucky to get our Caliper with Stoptech’s new electroless nickel finish.  This is a nickel plating that won’t discolor or burn off with heat and is shiny, very corrosion resistant and easy to keep clean.

The ST60 front caliper has six pistons of differing diameters to prevent taper wear of the pads. Brake pads tend to wear faster on the leading edge and develop a tapered wear pattern from front to back. The ST60 uses smaller leading edge pistons and larger trailing pistons, so there is more clamp force on the trailing, slower wearing tail of the pads and less on the fast wearing leading edge. This assures even wear and longer pad life. Stoptech calipers also have dust boots made of high-temperature silicone. Most racing type calipers don’t have these, as they tend to burn up in track use.  For street use, having no dust boots affects the service life. This is a good feature for us as the car will see some limited street use.

The calipers have stainless steel abutments where the pad backing plates touch the caliper body to protect the forged aluminum from the wear of the brake pad backing plates. Without them, the backing plates can wear grooves into the alloy body which can cause sticking and inconsistent action. You can also see more of the extensive CNC lightening cuts and pocketing on the caliper’s bottom.

The top of the caliper features a massive bridge assembly that spans the caliper’s open midsection. The bridge really contributes to stiffness. For brakes, system stiffness equates to a firmer pedal and more precise modulation. The bridge contributes greatly to the STR-60 having class-leading stiffness.

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