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Lambda, Lambda, Lambda

“Would you rather live in the ascendancy of a civilization or during its decline?” —Arnold Poindexte...



Off Road Enclave

Buick’s Enclave is the latest, but not last, member of GM’s Lambda crossover family to hit the market. (Chevrolet will get a version to replace the Trailblazer, which has suffered at the hands of high gas prices and buyers looking for utility vehicles with more refinement than body-on-frame entries can muster.) It is not, however, just a lightly modified clone of its siblings.“We used two-piece doors on the Enclave as it was the only way to get the thin upper section that would give the look and flush fit we wanted,” says Todd Pawlik, manager, Program Engineering on the Enclave program. “The doors are totally different than those on the (Saturn) Outlook and (GMC) Acadia, and we added a seal at the seam so that no ‘skunk stripe’ would appear between the front and rear doors.” Tight panel fits between panels also were a priority for the Enclave team as the design did away with ditches at major mating areas normally used to hide seams. “The front and rear fascias are two-piece designs with flush seams all around,” says Pawlik, and the lower side trim fits flush in a cavity designed into the body.” He says this means parts have to be straight out of the tool, and this required much greater attention to detail to get everything to work. “The designers didn’t make it easy,” he says.According to Ed Welburn, GM’s v.p.

Buick’s Enclave is the latest, but not last, member of GM’s Lambda crossover family to hit the market. (Chevrolet will get a version to replace the Trailblazer, which has suffered at the hands of high gas prices and buyers looking for utility vehicles with more refinement than body-on-frame entries can muster.) It is not, however, just a lightly modified clone of its siblings.

“We used two-piece doors on the Enclave as it was the only way to get the thin upper section that would give the look and flush fit we wanted,” says Todd Pawlik, manager, Program Engineering on the Enclave program. “The doors are totally different than those on the (Saturn) Outlook and (GMC) Acadia, and we added a seal at the seam so that no ‘skunk stripe’ would appear between the front and rear doors.” Tight panel fits between panels also were a priority for the Enclave team as the design did away with ditches at major mating areas normally used to hide seams. “The front and rear fascias are two-piece designs with flush seams all around,” says Pawlik, and the lower side trim fits flush in a cavity designed into the body.” He says this means parts have to be straight out of the tool, and this required much greater attention to detail to get everything to work. “The designers didn’t make it easy,” he says.

According to Ed Welburn, GM’s v.p. Global Design, those same designers zeroed-in on both an interior and exterior theme for the Enclave very early in the design process. “We fought to get the wheels outboard of the greenhouse to give it a more ‘planted’ look,” says Welburn, “and that is now the design standard at GM.” In addition, the Lambda vehicles are the first trucks with wheel and fender clearances not designed around the front wheels at full lock, the suspension in full compression, and tire chains in place on a vehicle traveling 50 mph. “That’s why wheel clearances are much tighter than in the past,” says Welburn. A good thing when 18-in. and 19-in. wheels are available and 20-in. wheels are in the wings for the Ultra V8-powered Enclave due in 2009.

According to Grace Lieblein, vehicle chief engineer, the standard P255/65-18 Goodyear tires went through a couple of iterations before she was willing to sign off on them, a move that had the rest of her team concerned. “The ride, handling, and other factors were within the targets we set for the tires,” she says, “but the rolling resistance numbers were below them. Everyone was worried that getting that number in line might adversely affect the others, but I insisted we try, and Goodyear came through.” Lieblein’s stubbornness also paid off with the use of dual-phase steel front and side rails, a first at GM. “The vehicle crashed just as our simulation showed it would, but those sections proved to be tough to form—real tough.”

Those words might also be used to describe the suspension, which features MacPherson struts with ball bearing isolated strut mounts and a direct-acting anti-roll bar up front, and a subframe-mounted independent linked H-arm design with coil springs and twin tube dampers in the rear. The front subframe features a K brace that handles both vertical and horizontal attachment of the steering gear to the frame, and has a stiffness of 20,000 N/mm which helps keep roll gain below 5? in cornering. ABS, electronic stability control with roll mitigation, traction control, and tire pressure monitoring are standard.—CAS