You’ve got your iron rotors, your carbon ceramic rotors, and now these: tungsten carbide coated rotors (PSCB), which offer some of the advantages of both.
SOURCE: Popular Mechanics
The white calipers are a baller move.
Porsche’s new Surface Coated Brake (PSCB) system uses white calipers, a nod to the fact that the mirror-finish tungsten carbide-coated rotors drastically reduce brake dust. There’s usually a compromise between brake pad performance and brake dust (high-performance pads tend to generate more schmutz on your wheels) but that’s not the only reason Porsche bothers to zap rotors with high velocity oxygen fuel, a process that looks like an extremely one-sided lightsaber battle.
PSCBs offer some other bennies, which is important since they’re a $3,490 option on the Cayenne S, though they’re Standard on the Cayenne Turbo.
On the track or during hard driving—given that we’re talking Cayennes, trailering could be relevant, too—a system with iron rotors is going to experience some brake fade as the rotors heat up. During testing, Porsche executed brutal high-speed stops that took both iron rotors and surface-coated rotors up to nearly 1,200 degrees Fahrenheit.
Over the course of 13 stops, they measured the change in pedal force required to haul down the vehicle, and while both systems required a firmer squeeze of the pedal, the PSCB rotors only experienced half as much fade as the iron brakes. Fun fact: on the Vickers hardness test, iron has a value of around 30 to 80 HV. Tungsten carbide is above 1,000 HV, which is why it’s so popular for drill bits.
Cayenne Turbo Specs: Engine: 4.0-liter twin-turbo V8, 541 hp and 568 lb-ft of torque / Transmission: eight-speed automatic / Top Speed: 177 mph/ Ground clearance: 9.6 inches (air suspension, high level) / 0-60: 3.7 seconds / Tow rating: 7,700 pounds /Base price: $126,500