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2008 Porsche Cayenne Turbo Review

Posted in Vehicle Reviews on May 1, 2007 Comment (0)
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Photographers: Porsche of North America

Introduced by Porsche amid financial uncertainty in 2003, the Cayenne elicited howls of derision from Porsche enthusiasts-and curious glances from everyone else. While the faithful lamented-heaven forbid!-an infidel SUV profaning the Pantheon of sportscars, Porsche marketers had the last laugh: Within two years of its introduction, Porsche was selling more Cayennes per year than all of its cars combined in North America, and saving its Stateside operations in the process.

We tested a Cayenne shortly after its debut, and despite its impeccable road manners and an impressive list of seemingly trail-oriented technical features, we found it a disappointment in the dirt. Now the Cayenne has undergone extensive reengineering for 2008, and as before will be offered in three trim levels. Would the new version fare any better on the trail?

The Porsche Dynamic Chassis Control employs a pair of hydraulic motors to apply lateral counterforces, using variable fluid pressures up to 2,600 psi, to the front and rear sway bars. The system is said to neutralize body roll at forces up to .65g-and best of all, the sway bars disconnect automatically in low-range.

For 2008, the Cayenne receives power boosts across the board. The base-model V-6, now displacing 3.6 liters, produces 290 hp, and the optional 32-valve 4.8L V-8, a punched-out version of the previous 4.5L, now offers 385 ponies underhood. For those of you (including us) who just can't get enough of a good thing, there's now a twin-turbocharged version of the 4.8L. The all-aluminum block is now direct-injected, runs 10.5:1 compression, and employs infinitely variable valve timing for improved efficiency and reduced emissions. With a turbo perched atop each cylinder bank delivering a peak 26 psi of boost, the 4.8 produces a peak 500 hp at 6,000 rpm and 516 lb-ft of peak torque at 4,500. Can you say zero to 60 in 4.9 seconds?

Backing the 4.8 is an upgraded version of the venerable ZF Tiptronic six-speed manumatic transmission (with more clutch plates and reinforced bearings) with Hill Hold and auto-Neutral tranny-brake functions, as well as continuously variable shift algorithms that adapt on the fly to your style of driving. As an alternative, owners of V-6 Cayennes can get a six-speed manual gearbox.

Inside, the Cayenne is, as you might expect, luxuriously appointed in quality materials. The suspension, Hill Hold, and low-range toggles, located aft of the tranny shifter, are intuitively placed and easy to work with, though the cluster of functions surrounding the Nav screen can take a little getting used to. New for '08, the Porsche's cruise control now works at speeds of up to 149 mph. Just so ya know.

The Cayenne's four-wheel-drive system (Traction Management, in Porsche-speak) utilizes a full-time transfer case with a 2.7:1 low-range and a clutch-pack center diff-lock that distributes engine power in a 32/68 torque split, front to rear, under normal operation. In low-range, the system can transfer up to 100 percent of available power to any single wheel, depending on tractive needs. In the past, we'd found this a mixed blessing-on the trail, it certainly provided plenty of power whenever we started to spin a tire, but to get it to engage, we needed to lean on the throttle, wait for the ABS to hook up, then hang on for dear life as hundreds of foot-pounds slammed abruptly into one side of the vehicle. (In one memorable case, this nearly resulted in a TC-induced rollover.) However, Porsche engineers informed us that the system had been reprogrammed for 2008 to run more smoothly and less intrusively. We resolved to find out for ourselves.

Base Cayenne and S models run on a four-wheel independent coil suspension comprising double wishbones up front, a multilink rear, and three-way-adjustable shocks all around. Turbocharged models, however, eschew coils for adjustable air springs, which, when raised to maximum ride height, provide an outstanding 11 inches of ground clearance. The trade-off to this elevation, though, is that it stiffens the spring rates to the point where you can forget about any discernible suspension travel-which translated, on previous models, into wheels suspended helplessly in mid-air, followed by more unruly barks and belches from the ABS and traction control.

The Cayenne's 4.8L V-8 utilizes twin turbochargers, mounted in parallel atop each cylinder bank, along with direct fuel injection and infinitely variable valve timing to generate 500 peak horsepower at 6,000 rpm. Porsche claims the turbocharged block can deliver 19 mpg overall, though our brief testing evinced less optimistic numbers.

How to remedy? Disconnecting the sway bars would certainly help, and thankfully, Porsche's new Dynamic Chassis Control system allows us to do exactly that. Employing a pair of hydraulic swivel motors (incorporated into each axle assembly), the DCC uses fluid pressure to essentially turn the Cayenne's sway bars into a pair of variable-rate longitudinal dampers. The primary purpose of this, of course, is to limit body roll in high-speed cornering by using the sway bars to generate lateral counterforces (which they do very well), but a nice side effect is that the sway bars automatically disconnect in low-range-and stay that way up to 20 mph. Eighteen-inch wheels and 255/55R18 (29-inch) tires are standard on the V-8 Cayenne, and 19-, 20-, and 21-inch blingers are available options.

We recently 'wheeled a top-line Cayenne Turbo, and based on our time behind the wheel, we can happily report that its trail manners would appear to be far superior to the previous model's. One thing we learned, and certainly didn't expect, was that our tester's 35-series Michelin Sports (yep, we wheeled on a set of 21s, and obviously at street pressures) delivered much better traction in the dirt than we'd have assumed them capable, given their virtually voidless tread pattern. (It should go without saying that they're outstanding on pavement.) It took us some effort to get them to spin, but spin they eventually did-on a loose-shale hillclimb-and this was where we learned that the Cayenne's traction-control system is indeed more refined and driver-friendly now. Where previous engagements had resembled a drunken ballet, there was now a much smoother transition from spin-up to hook-up, with only slight levels of ABS feedback and no need for extra throttle. We also noted the tires' ability to stay planted on the trail, despite our best efforts to cross them up on off-camber ledges, so we'd have to surmise the new sway-bar disconnect does its thing very well, too (Porsche claims it provides an additional 9 inches of travel). Naturally, we wouldn't advise taking the Cayenne out for any rockcrawling duties, or anything else that would require airing down (not with a 35-series sidewall, anyway), but as a moderate-duty trail rider, the new Porsche seems quite the able performer now.

For brevity's sake, we'll spare you the details of the Cayenne's pavement prowess, but suffice to say, our test Turbo's on-road ride, handling, and acceleration and braking characteristics were about what you'd expect from a 500hp, $93,000 German-engineered SUV: Himmel am Erde. Any time Porsche wants to loan us a long-termer, we're game.

We should have a Cayenne in our stable for next year's Four Wheeler of the Year test .... Are those howls of derision we're hearing out there? Watch out-you never know who'll have the last laugh.

Quick Specs
Vehicle/model: 2008 Porsche Cayenne Turbo
Base price: $93,700
Engine(s): 4.8L twin turbocharged V-8
Aspiration: Direct fuel injection
Compression: 10.5:1
Max hp & torque (lb-ft) @ rpm: 500 @ 6,000/516 @ 4,500
Transmission: ZF Tiptronic six-speed automatic
Transfer case: Full-time two-speed
Low-range ratio: 2.70:1
Frame type: All-steel unibody
Suspension (f/r): IFS, double wishbones, air springs/IRS, multilink, air springs
Axle ratio: 3.27:1
Max crawl ratio: 36.6:1
Rated top speed (mph): 171
Steering: Power rack-and-pinion
Brakes (f/r): 14.5-inch discs, six-piston calipers/14-inch discs, four-piston calipers
Wheels (tested): 21x10J Sport alloy
Tires (tested): P295/35R21 Michelin Sport PS2
Wheelbase (in): 112.4
Length (in): 188.8
Height (in): 66.7
Base curb weight (lb): 5,193
Approach/departure angles (deg): 32/25
Minimum ground clearance (in): 11.0 (max ride height)
Max payload (lb): 1,598
GVWR (lb): 6,791
Max towing capacity (lb): 7,718
Observed mileage (mpg): 13.0
Fuel capacity (gal): 22.0

What's Hot:
Well-mannered traction control, great brakes, disconnecting sway bars, ungodly acceleration.
What's Not:
Still homely, still gas-hungry, still hopelessly out of our budget.
Our Take:
For the 'wheeler who has everything, the ultimate in Trailable Excess.

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