2001 Acura MDX

First Drive
Here's the story: Acura is so proud of the new all-wheel-drive system in its fresh, clean-sheet MDX sport/utility vehicle that it invited us to the Colorado high country-still covered in a four-foot base of snow-just to check out the vehicle's low-traction capabilities.

Basically, Acura has chosen not to follow the new four-wheel-traction-control school of design that's been popularized by the Mercedes-Benz M-Class and BMW X5, opting instead for a new twist on an old theme. Like the Ford Explorer's Control Trac system or the Infiniti QX4's All-Mode 4WD, the MDX uses a system that automatically switches between two- and all-wheel drive as needed. The key differences are that the Acura's system is electronically controlled with innovative new programming and can provide an infinitely variable transfer of power between the front and rear wheels.

In a normal even-throttle, highway cruising situation, the MDX operates in front drive only. This provides better fuel economy and less mechanical wear, while optimizing braking performance. Any time the vehicle is accelerating, though, torque from its 3.5-liter/240-horsepower VTEC V-6 is automatically routed to the rear wheels-up to a maximum 45/55 front/rear split-to provide maximum forward traction. The amount of power proportioned to the rear is seamlessly variable and is determined not only by throttle position, but by the chosen gear, as well. In higher gears-third, fourth, and fifth, for instance-the acceleration has to be progressively more aggressive to initiate AWD.

Unlike other systems, this one doesn't wait to detect a slipping wheel before shifting into all-wheel drive. Although, if the system does sense a loss of traction at a front wheel, it also will direct power rearward regardless of throttle position. In addition, for situations that require maximum traction at all times, the MDX includes a lock feature in first, second, and reverse gears that disables the variable-control function for "always-on" AWD.

We got to drive the MDX both on slick, hard-packed snow-laden roads and a specially designed snow course. On both, the MDX proved well equipped to handle the low-traction conditions, exhibiting excellent forward traction, as well as unusually good steering and handling control. The SUV felt securely and consistently pinned to the road, despite the slippery conditions. Plus, unlike traction-control-based systems that stem slipping by applying a brake(s) and/or cutting engine power, there's no interruption of power delivery with Acura's system. When your foot gets on the throttle, there's always a response.

While our driving on this outing was limited to snow conditions, we'll next take the MDX to the jungle of Belize for a real torture test.