PreviewsAlthough the availability of a “real” SUV in the form of the B9 Tribeca bumped overall Subaru sales past the 200,000-unit mark in 2006, sales of the controversially styled mid-size SUV were considered mediocre. In response, Subaru has brought out a hastily revised version. The new Tribeca (thankfully, the confusing B9 prefix has been dropped for the 2008 model) features fairly comprehensive front and rear styling revisions, replacing the controversial Alfa Romeo–like cues with more conventional treatments that more closely resemble the Chrysler Pacifica, particularly with the badge set within a band of chrome atop the grille. Perhaps Subaru should have called it the Chry-beca.
Better, however, is the charming flat-six powerplant, which has been boosted in capacity from 3.0 liters to 3.6 liters in the interests of improved performance and economy, with horsepower and torque bumps to match.
Here’s where it gets interesting
The flat-six engine (or H6, as Subaru calls it) is already a tight fit in the Tribeca’s engine bay. Since the H6 is a horizontally opposed layout, any significant increase in crankshaft stroke would result in increases in engine-block deck-height that would make the engine too wide to fit in the existing structure.
The problem was exacerbated by typically thrifty computer-aided engine design, which left minimal space between the engine’s cylinder bores. Subaru calculated that it could safely increase the bore size from 89.2mm to 92.0mm, but that change would have bumped the displacement to only 3191cc. Subaru needed more than that for the performance improvements it was seeking, so it came up with a novel way of increasing piston stroke without raising the cylinder deck height. The answer was an asymmetrical connecting-rod design (which looks somewhat like a lamb chop) that permits the piston to travel farther downward into the crankcase and increases the effective stroke from 80mm to 91mm.
Increasing both bore and stroke has resulted in the 3.6-liter displacement figure, a growth of 0.6 liter, with substantial gains in power and torque. The new engine produces 256 horsepower at 6000 rpm versus 250 at 6600 in the previous engine. Better, however, is the torque peak of at 247 pound-feet at 4400 rpm versus 219 at 4200, and about 180 pound-feet are now available at engine speeds as low as 1200 rpm.
Driving ImpressionsAlso welcome news, as gas prices climb again, is that various tuning revisions have altered the engine’s octane requirement from premium to regular, promising substantial cost savings to Tribeca owners. And, in spite of the engine’s newfound strength, fuel consumption remains the same as in ’07, according to Subaru, which estimates EPA ratings of 16 mpg city and 21 highway by the EPA’s new 2008 model standards.
During the engineering redesign process—which pared about 10 pounds off the engine’s weight—Subaru altered the cooling system from one where cylinders receive the coolant flow sequentially to one where separate ducts provide each cylinder with its own fresh supply. This more-equal cooling strategy allowed the engineers to advance the spark timing by one degree, yielding six pound-feet of torque in the process.
The overall improvement in torque delivery permitted revisions to the transmission torque converter and shifting strategies, greatly reducing the amount of hunting and downshifting that is considered annoying by current Tribeca owners. The result, says Subaru, is a more flexible and tranquil drivetrain, with improved throttle response, a more flexible operation, and better performance with lower operating costs.
Driving Impressions
It sounds like a tall order, and we got our first chance to drive the Tribeca recently to confirm whether Subaru was blowing sunshine up our bums. What we found is a very well-balanced, stable, and confidence-inspiring ute—just like its predecessor—only faster.
The larger motor is quite prolific, with increased torque all through the rev range, making squirting through the mountains south of Palm Springs, California, a brisk affair. The manumatic transmission makes it easy to keep revs high, where most of the fun is, though we wished for steering-wheel-mounted paddles in addition to the floor-mounted deal. That said, it’s rare that a sport-ute drives well enough to prompt us to shift ourselves, so we’ll consider ourselves fortunate.
Turning the steering wheel is met with predictable response and nice feedback, requiring just enough effort to feel engaging without being exhausting. On the highway, we appreciated the excellent on-center feel. Body motions are beautifully managed thanks in no small part to the low mounting of the lightened H-6. So enjoyable is the ’08 Tribeca to fling about, that if you had your eyes closed, you might swear you were driving the previous-gen BMW X5 3.0i, provided your ears weren’t expecting the whirr of Bimmer’s distinct I-6.
SpecsThe Sum-Up
While we welcome the enhanced drivability of the Tribeca, we aren’t convinced the styling is an improvement—indeed, there are several among us who sort of liked the funky, boldly different schnoz of the previous model and are unimpressed with the sanded-down version.
The Jetson-inspired interior is no different—not a bad thing, but we also were reminded of just how tight the Tribeca’s second-row seat is when there’s a third-row behind it (two-row Tribecas have much more space in the back seat).
Perhaps when the Tribeca is completely redesigned, say, in 2011 or 2012, Subaru will remedy the Tribeca’s cramped rear quarters, and finally get the front end right. They got the engine part down, which is an excellent place to start.
VEHICLE TYPE: front-engine, 4-wheel-drive, 5 or 7-passenger, 5-door wagon
ESTIMATED BASE PRICE: $30,150
ENGINE TYPE: DOHC 24-valve flat-6, aluminum block and heads, port fuel injection
Displacement: 220 cu in, 3600cc
Power (SAE net): 256 bhp @ 6000 rpm
Torque (SAE net): 247 lb-ft @ 4400 rpm
TRANSMISSION: 5-speed automatic with manumatic shifting
DIMENSIONS:
Wheelbase: 108.2 in
Length: 191.5 in
Width: 73.9 in
Height: 66.4–67.7 in
Curb weight: 4150–4200 lb
PROJECTED FUEL ECONOMY (MFR'S EST):
EPA city/highway driving: 16/21 mpg
BY JARED GALL AND STEVE SILER
caranddriver.com
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