Comparison Tests
It’s finally happening. Station wagons are becoming cool. Cool enough for 10 marques to have displayed new wagons at January’s Detroit auto show (see Upfront this issue). Okay, practically none of them used the dreaded “station wagon” terminology (only Kia’s Rio display was emblazoned with this antique moniker). Euphemisms on the show floor ranged from Mazda’s Protegé 5, to Lexus’s IS300 SportCross, to Audi’s S6 Avant. All of the above are unabashedly sporty station wagons. Still other manufacturers dodge the terminology trap by introducing new wagons that share no visible parts with any other vehicle type, à la PT Cruiser. These included the sporty Pontiac Vibe and Toyota Matrix cousins, and the ovoid Daewoo U100 (a.k.a. Rezzo).
Having championed the sport-wagon cause so long and loudly, we were only too eager to fan this spark of auto-show interest. We were also desperate to find something to test that was capable of coping with the snowiest winter Michigan has seen in years, so we narrowed our wagon search to four-byfours, with prices clustered around the $30,000 mark. There are currently four: Audi’s A4 Avant, the BMW 325xi, the Subaru Outback H6-3.0, and the Volkswagen Passat V-6.
It also helped that during the planning stages of this test, Delphi Automotive Systems’ manager of vehicle performance, Scott Badenoch, called to invite us for a test drive of the supplier’s new winter test facility on the grounds of the former K.I. Sawyer SAC air base just south of Marquette in Michigan’s Upper Peninsula. This controlled environment would allow us to shake down the various four-wheel traction solutions (see sidebar), while the 400-mile drive each way on wintry roads would easily cement our opinions of these cars as snowmobiles.
All-wheel drive comes standard on all Subaru and Audi wagons bound for the U.S. (on A4 sedans it adds $1750). BMW’s “xi” all-wheel-drive system also adds $1750 to the price and is expected to find its way onto half of all 3-series wagons and a quarter of sedans. VW expects half of all V-6 Passats to be ordered with 4Motion, priced at the going rate of—you guessed it!—$1750.
The A4 Quattro and Passat 4Motion systems are identical. A center differential apportions torque equally between the front and rear axles under normal driving conditions. When a wheel spins, a Torsen limited-slip device on the center diff routes more torque (up to 67 percent) to the axle with the best grip. Once it gets there, an electronic system uses the brakes to apportion torque from side to side. Audi now offers a $550 electronic stability program on all A4s to prevent slides and spins (complete with an enthusiast-friendly “off” button), but our test car lacked this option.
The BMW system, shared with the X5, employs a planetary center differential that permanently apportions 38 percent of the torque forward and 62 percent to the wheels that traditionally motivate BMWs. When slippage occurs, the standard traction- and stability-control systems step in to arrest a spinning wheel. Depressing the “DSC” switch on xi models doesn’t completely disable the system but sets its control parameters to allow much more slippage before intervening.
Subaru’s top-of-the-line Outback H6-3.0 VDC also uses a planetary center differential, which normally splits thrust 45/55 front to rear. But when the “Vehicle Dynamics Control” stability system senses wheel slippage or an impending slide, it instructs a hydraulic clutch on the center diff to redistribute torque and then begins to apply braking and, if necessary, fuel shutoff to regain control. Sadly, the VDC system can be neither canceled nor cajoled into allowing even the least little bit of slidy fun.
Armed with this understanding of our hardware, plus snatch straps, snow pants, flares, radios, and various E-rations, we stared into the face of Old Man Winter and pointed our wagons north.
