The 2008 Toyota Sienna features an extremely robust powertrain in an extremely relaxed chassis.
Offering perhaps the Sienna’s only draw for the enthusiast is Toyota’s gem, the corporate 3.5-liter DOHC V-6. Blessed with dual variable valve timing for the best of low-end torque and high-end power, its 266 horses and 245 pound-feet of torque make it “the strong, silent type, rushing to 60 mph in 7.2 seconds” by Car and Driver’s stopwatch. Fleet performance for a family carton, indeed. Kelley Blue Book attests the engine “delivers where it counts,” and comparing it to the 3.3-liter V-6 it replaced, Edmunds admits “there's no denying the potency of the new V6 when you step into it.”
The only transmission offered is a five-speed automatic that's generally praised for the smooth, responsive way it transmits the V-6’s power to the ground. Edmunds complains that the Sienna’s “automatic transmission is calibrated more for fuel economy than performance and thus tends to shift conservatively,” probably appropriate for a minivan as well as for economy. Kelley Blue Book, however, contends the transmission “makes the most of the engine's torque curve before seamlessly shifting to the next gear.” Regarding this marriage of engine and transmission, Car and Driver concludes, “if choosing a minivan came down to the powertrain, this Toyota would be a slam-dunk.”
And that’s about it for the Sienna’s rave reviews. Handling is pretty ponderous, Car and Driver faulting the “the generally aloof responses of the controls. The brakes feel wooden…the steering lacks sharpness.” On a positive note, those brakes are four-wheel discs, unlike the previous-generation Sienna, which makes do with drums on the rear. And despite its front-wheel drive, the Sienna manages “a tidy turning circle of 36.8 feet…the envy of several passenger cars,” claims Car and Driver. “The Sienna offers little inspiration in the handling department,” says Edmunds, noting that it “feels secure enough” but offers “minimal steering feedback and considerable body roll,” as well as brake pedal feel that is “too soft.” Even the non-enthusiasts over at ConsumerGuide note that “tire grip seems only adequate and the steering is a tad overassisted.”
Perhaps making up for its lack of athletic moves, Car and Driver, in a comparison test involving other competitive minivans, asserts that “what you get instead of confident handling is a soft, quiet ride that makes the others seem a bit rude.” Edmunds also makes note of the “softly tuned suspension,” and ConsumerGuide finds the van to be “Comfortably composed. Large humps and dips induce some body bounce, but the suspension irons out most rough pavement.”
Despite its athletic acceleration, the Sienna offers competitive EPA ratings of 17/23 mpg with front-wheel drive, and 16/21 mpg with the optional all-wheel drive, both competitive figures for the class (or in a class of its own, in the case of the AWD).