By Greg N. Brown
Exploring a vehicle's dynamic limits will, on occasion, cause us to be rough on the hardware. It's not that we enjoy smoking clutches, boiling brakes, or atomizing tires (okay, maybe a little), but heavy-footed manhandling is an often unavoidable part of discovering all we can about the mount under lash.
Larger, aluminum intercoolers and a boost in turbo pressure are responsible for this ueber-'ute's 520 horsepower and 168-mph top speed, but those figures were simply sidebars to our first drive. Dubai's modest speed limits, numerous speed cameras, and herds of wandering camels kept our on-pavement behavior well under control--but that all changed when the pavement ended. The Cayenne can take an impressive amount of punishment without stumble or grumble as its permanent four-wheel drive collaborates with the electronically sophisticated Porsche Traction Management (PTM) and air-spring suspension (with six different levels of ground clearance) to pull its 5200 pounds through, up, and over most obstacles with ease.
In normal on-road conditions, PTM sends 62 percent of the engine's torque to the rear wheels, echoing standard Porsche practice and supplying the sport-minded driver that coveted rear-drive dynamic. If the system detects a lack of traction at either axle, such as on slippery pavement, ice and snow, or over not so firm ground--PTM then can transfer the lion's share of the twin-turbo V-8's power to the axle with grip through a longitudinal differential lock. Should the going get really rough, the driver can select a low-range mode, where-upon PTM works through a reduced-ratio off-pavement gear and recalibrates the control settings for the ABS, traction control, and the center differential and also raises the ride height by just over an inch. And if the terrain becomes especially difficult, where individual wheels might lose contact with the ground, actuating the low-range switch a second time provides a locked drive system for even better traction and increases ride height to 10.8 inches.
For hard-core dirt-pounders, an optional Advanced Offroad Technology Package adds a rear-axle differential lock, special side protection, a system that decouples the anti-roll bars for greater wheel articulation, and a steel plate under the floor panel around the radiator.
In addition to the enhanced powertrain, the Turbo S offers larger brakes, modified suspension components, revised software controls for Porsche's Active Suspension Management, and 20-inch wheels with 275/40 all-season radials specially designed for the Cayenne and good for speeds up to 186 mph. Deep sand is tough to negotiate without special tires made for this purpose, but the Cayenne became mired in the fine-grained sand of the region only when we failed to apply enough throttle to plow through the deeper holes. Our foray into the dunes required nothing more than a reduction in tire pressures. A tire-pressure monitoring system is standard, and an on-board compressor and pressure hose allow reinflation when the vehicle returns to civilization.