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Sienna is a big vehicle, yet it never feels overly bulky and it's never hard to handle or park. It's generally smooth, responsive and quiet, and compared to many family vehicles with comparable functional capability, it's relatively fuel efficient. An owner won't feel guilty or excessive driving it empty for errands. On long trips or school runs, loaded with people or just the driver, the Sienna is always comfortable and pleasant to drive.
The more powerful engine that's been used starting with the 2007 models nudged the Sienna closer to actually being fun. The 3.5-liter V6 features the latest in control and materials technology, including four-cam variable valve timing (Dual VVT-I in Toyota parlance). VVT-i helps reduce emissions and deliver more power without increasing fuel consumption. The 3.5-liter V6 generates 266 horsepower and 245 lb-ft of torque. That gives Sienna class-leading horsepower and puts it near the head of the class for torque.
We never considered previous Siennas underpowered, but the new engine makes it a hot rod among minivans. By the seat of our pants, we'd say that the Toyota is now the quickest accelerating minivan you can buy, bar none, despite its hefty overall weight (more than 4500 pounds for loaded all-wheel-drive models).
Yet the hot-rod quality extends beyond acceleration. The 3.5-liter V6 is so powerful that it responds aggressively, even abruptly, to anything more than a bit of gas. A driver may jerk some heads until he or she gets a bit of practice and adjusts to the throttle response. Moreover, peak torque and particularly peak horsepower come fairly high in the engine's rpm range. We wanted to keep the gas pedal floored well past respectful cruising speeds just to keep the engine pulling toward peak output and to feel maximum acceleration. The V6 remains smooth and relatively quiet all the way to the redline on the tachometer.
Gear ratios in Sienna's five-speed automatic help exploit all that power, and the engine and transmission interact nicely. At steady speeds, the transmission keeps the engine purring at fairly low rpm. Yet if the driver floors the accelerator, the transmission immediately kicks down a gear or two, and holds that gear all the way to the redline before shifting up again smoothly and smartly. A low first gear offers quicker response off the line; the overdrive fifth gear means lower engine speeds when cruising, which translates into less engine noise and better gas mileage. Even the EPA's new and more pessimistic estimates credit the FWD Sienna with 17/23 mpg city/highway; and the AWD model with 17/21.
The same balance of smoothness and response in the engine/transmission package applies to the Sienna's ride and handling. On curving mountain roads in Southern California, the Sienna drives more like a car than a minivan or sport-utility. Its steering is responsive and there's only a little body roll, or lean, when cornering.
Transient response is good, meaning the Sienna can quickly change directions without losing composure. It feels stable at high speeds. The steering is nice and light at low speeds. The Sienna is easy to maneuver through tight parking lots or make U-turns; that's thanks to a turning radius of less than 37 feet, tighter than most minivans.
The ride, too, is generally very comfortable, helped by a long wheelbase that limits chop, or bounce, over recurring pavement joints. On smooth pavement, few will notice any more suspension movement or roughness than one experiences in a typical sedan. On rough pavement, the Sienna's solid rear axle makes its presence known, lacking the sophistication of an independent rear suspension.
Braking is smooth and the brakes perform well. Making big 16-inch wheels standard equipment allowed Toyota to equip Sienna with big disc brakes. It's also equipped with all the latest electronics: anti-lock brakes (ABS) with electronic brake-force distribution (EBD) and Brake Assist. EBD distributes the braking force to the tires with the most traction for quicker, more stable stops. Brake Assist maintains full brake pressure during emergency stopping situations, even if the driver inadvertently reduces pedal pressure in the excitement. All this alphabet soup adds up to stable, controlled stopping ability when you really need it.
Toyota's Vehicle Stability Control (VSC) with Traction Control is also now standard on all Siennas. Our real-world experience, backed by a number of studies, suggests that such electronic stability systems do help prevent accidents. VSC senses a potential skid and uses the brakes to compensate and correct the vehicle's trajectory. Traction control helps reduce tire slippage during acceleration. In short, it helps you maintain control of the car.
Given all these active safety features, we recommend the Sienna's optional all-wheel-drive system only to drivers who live in rural areas and travel frequently in deep snow or on gravel roads. All-wheel drive is vastly superior on snow and ice, but a front-drive Sienna can handle most winter driving in the Snow Belt and the AWD costs a few miles per gallon. next page