Written by Dan Carney

Porsche&quot;s pioneering Cayenne crossover SUV enters its third generation in2018 following six-year runs of both the first- and second-generation models.In its latest iteration, new technology permits the Cayenne to get ever closerto reconciling the conflicting priorities of its Porsche sports-car heritageand its SUV off-road expectations. <br /> The 2018 Cayenne is helped in its progress toward this by alighter-yet-stronger unibody structure made with both aluminum and various gradesof steel; it is Porsche&quot;s interpretation of the Volkswagen Group&quot;s MLB Evoplatform, which debuted in 100 mm-longer form as the Audi Q7. The MLB Evo architecture replaces the previous Cayenne&quot;s rubber bushing-mounted steelfront subframe with a new bearing-mounted aluminum subframe that is lighter andcontributes to improved steering response. <br /> Much of the body-in-white is aluminum, including the roof,floorpan, front section, doors, fenders, hood and hatch. This is strategically reinforced bymicro-alloyed high-strength steel and multi-phase steel to producea body that is 20% more rigid than that of the outgoing model whiletrimming 298 lb (135 kg) from the bodyshell. <br /> Some of the hard-won weight savings was lost due to the increase in standard equipment that reduced the final curb-weightreduction, reported a dismayed-sounding Karl Heess (pronounced &quot;Hayes&quot;),chassis director for the SUV product line. <br /> The 2,020-kg curb weight of the Cayenne S, for example, is 143lb (65 kg) less that the previous model. Because of differences in standardequipment, the 4,376-lb. (1,985-kg) base Cayenne saves 121 lb (55 kg), whilethere is a paltry 22 lb (10 kg) reduction for the 4,795-lb (2,175-kg) CayenneTurbo. Ten kg of every model&quot;s savings is attributable to thesubstitution of a lightweight lithium-ion battery in place of the lead-acidbattery used previously. Much of the Turbo&quot;s extra weight can be attributed to itsgargantuan brakes. They are 16.34-in (415-mm) cast-iron front rotors squeezedby suitably enormous Akebono 10-piston monobloc aluminum front calipers and 14.37-in (365-mm) cast-iron rear rotors with Brembo four-piston monobloc aluminumcalipers. The oversized brakes are a necessity for such a heavy vehicle propelled by a550-hp, twin-turbocharged 4.0-L V8 engine capable of producing3.9-sec 0-60 mph (0-97 km/h) acceleration and a top speed of 178 mph (286 kph) <br /> The base Cayenne uses 13.8-in (350-mm) front brakes with four-pistonmonobloc aluminum calipers and 13-in (330-mm) rear rotors with two-pistonaluminum monobloc calipers, while the Cayenne S employs larger 15.35-in (390-mm)front rotors with six-piston aluminum monobloc calipers and 13-in rearrotors with four-piston aluminum monobloc calipers. All of these components areBrembo-supplied. All of the Cayenne&quot;s cast-iron rotors have a tungsten-carbidecoating, which both boosts rotor life by 30 percent and reduces the amount ofwheel-dirtying brake dust produced. <br /> All-turbo engines <br /> Twenty-one-inch wheels are standard on the Turbo to provide necessaryspace for the huge brakes, while 19-inch wheels are standard on the base and Smodels, with 21-inch wheels available optionally. <br /> The base engine is a 340-hp single-turbo 3.0-L V6, while the Senjoys 440 hp from a 2.9-L twin-turbo V6. Both engines are from the samefamily, but the larger one has a 3-mm-longer stroke. A plug-in hybrid-electricand a diesel will follow, but the company declined to provide details on thoseversions. <br /> All three gasoline-powered models use an 8-speed ZF Tiptronic Splanetary automatic transmission with an added &quot;hang-on&quot; power take-off todrive the front wheels. This is a difference between the rear-drive-biasedCayenne which can send 100% of its power to the rear wheels and theAudi Q7&quot;s quattro full-time all-wheel drive system that&quot;s always dividing drive torque between front and rear axles. Vibracoustic damping, rear-steer<br /> Heess pronounced the biggest technical challenge for the chassisteam to be the development of the new three-chamber Vibracoustic air suspensionsystem that lets the Cayenne so effective marry its conflicting goals ofcomfort and agility. The air suspension is standard equipment for theTurbo, while conventional steel springs are standard on all other models, withthe air suspension available optionally.&nbsp; <br /> The new three-chamber system provides a greater range of dampingrates, which is especially beneficial in hard driving because thesmallest-volume chamber now provides very high rates, according to Heess. <br /> Ground clearance varies between 6.37 in. (162 mm) and 9.64 in. (245mm), depending on whether the driver has selected the Normal, Sport or Sport+driving mode. The Cayenne automatically drops to its lowest height when drivingfaster than 130 mph (210 km/h) for reduced drag and improved stability; itcan crouch even lower when parked for easier loading of luggage. <br /> The Cayenne&quot;s balance of sport and comfort also benefits from anew Schaeffler Group-supplied 48-volt Intelligent Active Roll Control roll-stabilization system, which can completely disconnect the anti-roll bar, as whendriving off road and maximum suspension articulation is desirable and to applyas much as 885 lb ft (1200 N m) of resistance to roll during hard cornering. The previousCayenne used a hydraulically-powered active roll bar, which was replacedbecause the electric system is more compact, responds faster and uses lessenergy. A new feature for the 2018 Cayenne is a rear-wheel steering systemthat can turn the wheels as much as 3 deg in either direction. At speedsbelow 50 mph (80 km/h), the rear wheels turn in the opposite direction to thefronts, providing improved agility and reduced turning radius for parking. Theturning circle is reduced from 39.7 ft (12.1 m) to 37.7 ft (11.5 m). Above 50 mph (80 km/h), the rear wheels steer in the samedirection as the fronts, for improved stability, especially during lane-changemaneuvers. <br /> The new Cayenne is the first Porsche model to bring all thesedisparate chassis-control solutions under the common command of an integrated system dubbed calledPorsche 4D Chassis Control. Previously, each subsystem had its own sensors andcontrol module, but the new 4D system coordinates all the subsystems centrally,providing control that Porsche considers to manage the fourth dimension, time,by acting proactively to anticipated events. We can anticipate that the base Cayenne and the S will arrive in theU.S.mid-2018, with the Turbo available later in the year.

Date written: 14-Nov-2017 01:31 EST

More of this article on the SAE International Website

ID: 9934