Two Cayenne S models try to out-stop one another.
A few years ago, Porsche first introduced its new Porsche Surface Coated Brake (PSCB) system. While more potent stoppers in the form of ceramic composites have been available for a much longer time, they're prohibitively expensive, while conventional braking systems produce brake dust and are prone to rusting. PSCB solves most of these issues thanks to the use of tungsten carbide on its surface, a material that is one of the hardest in existence after diamond; it's so hard, in fact, that it could be used to cut glass.
Back when the technology was announced, the head of Porsche's brake division and the pioneer behind PSCB, Matthias Leber, said, "believe me, it was a long road getting here. Otherwise, we would have offered it ages ago." With all the fanfare, is PSCB really a shining example of modern braking tech? Car and Driver decided to put these brakes to the test, and the results were mixed.
Using a Porsche Cayenne S fitted with the $3,490 PSCB option, the testers compared it with another Cayenne S, the latter using the stock rotors without the tough coating. It's worth noting that the PSCB rotors are also larger by an inch in front and 1.4 inches at the back. Both SUVs rode on the same tires and, in a stop from 70 mph, the Cayenne with the PSCB brakes stopped in 152 feet - the standard model needed 155 feet to come to a halt from the same speed. Tested from 100 mph, the stock Cayenne S required an extra eight feet to stop, a more substantial difference.
So, it's clear that the PSCB system allows for shorter stopping times, even if the differences aren't groundbreaking at lower speeds. There was minimal difference in terms of fade, though, with both braking systems holding up well in a series of 18 stops from 100 mph. One criticism noted for the PSCBs is that they are more difficult to modulate under regular braking at lower speeds.
And what about the dreaded brake dust? Here, the PSCB system demonstrated a clear advantage, with the alloys remaining largely dust-free following over 20 hard stops, whereas the standard brakes had darkened the insides of the alloys. Whether cleaner wheels are worth $3,490 is a decision you'll have to make when purchasing a new Porsche (unless, of course, you go for the Cayenne Turbo, which gets the PSCBs fitted as standard).
Still, that's a lot less expensive than the whopping $9,080 required to upgrade to Porsche Ceramic Composite Brakes (PCCB) on the base Cayenne. As an aesthetic upgrade, the upgraded brakes will maintain their shine better behind the alloys, while the superior stopping power at higher speeds could be the difference between disaster or a safe stop in a worst-case scenario. Just be sure to take a PSCB-equipped Porsche for a test drive to make sure the brakes are easy enough to live with for your daily commute.