As a late addition to the 2007 lineup, the ninth-generation S-class adds 4MATIC all-wheel drive to the option list. Although past S-classes have also had this choice, the system has been completely overhauled for the latest S550 (within the S-class range 4MATIC is only available on S550s).
Perhaps the best news is that the new system, developed 100-percent in-house by Mercedes, is now teamed with the company’s excellent seven-speed automatic. For now, the new all-wheel drive is exclusive to the S550—the E-class 4MATIC models keep the old version with the five-speed tranny, and while the all-wheel-drive SUVs have the seven-speed, it’s a different setup. However, a version of this latest all-wheel drive will be available shortly on the redesigned 2008 C-class.
The new 4MATIC system is reportedly 60 pounds lighter than the old one, making an S550 4MATIC just 145 pounds heavier than a standard S550. That massive weight reduction was accomplished by using aluminum front axles instead of steel as well as eliminating the transfer case altogether by incorporating the planetary center differential into the transmission case. That second bit also saves on complexity: S-class 4MATICs no longer require a separate, wider transmission tunnel. Mercedes claims the friction within the system has been reduced as well, and reports a 60-percent reduction in the fuel-economy penalty of its all-wheel drive. But we’re a bit skeptical of that claim as the S550 4MATIC’s fuel economy drop according to EPA ratings is 1-mpg city and 2-mpg highway (15/22 versus 16/24), nearly identical to the previous S-class’ ratings.
Other changes include a switch from a 40/60 front-to-rear torque split to a fixed 45/55 split for better dynamic handling, says Mercedes. In slippery situations, the standard stability control (which also includes traction control) ensures that torque gets to the appropriate wheels. In practice, we were hard pressed to notice any seat-of-the-pants difference between rear-drive and all-wheel-drive S-class models, which was likely Mercedes’ goal. Either way, occupants are coddled in soft and supportive leather seats and are treated to a divinely supple ride. Of course, the S550 still feels big and heavy—because it is—and even though the steering and chassis aren’t quite as communicative as competitors’ such as the Audi A8 or BMW 7-series, we think the S550 is the best compromise between sportiness and luxury, which is why it prevailed in a comparison test amongst four of its peers.
The 4MATIC version of Mercedes’ largest sedan is powered by the same 382-hp 5.5-liter V-8, and Mercedes predicts the same 0-to-60-mph time as well, although we think the all-wheel-drive version should get off the line quicker and could therefore beat the class-leading 5.3 seconds to 60 mph that our quickest, rear-drive S550 managed.
But, starting at $90,825, which includes an extra $3300 for 4MATIC, fabulousness doesn’t come cheap.
source: www.caranddriver.com
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