DISCOVERY SERIES II TECHNOLOGY HIGHLIGHTS

The new Discovery Series II is so chock-full of engineering innovation, it may well be the most technically advanced sport utility you can buy. A bold statement? Here's the engineering behind the claim.

Thor & ZF

Car companies like to talk about horsepower, but torque is what brings a smile to a driver's face. Torque is pulling power. And Discovery Series II's 18 pound-feet of additional peak torque, delivered at a 400-rpm- lower engine speed, is immediately apparent. With the same displacement as last year's model, the Series II's "Thor" V8 received some significant engineering improvements to achieve such gains. A new intake manifold with longer tracts and two plenum chambers speeds the flow of air into the engine. That, by itself, increases torque.

The engine's electronic management system is also new, using the latest Bosch Motronic 5.2.1 system to control fuel, ignition and some emissions functions. This results in a smoother and more consistent idle, fast warmup and lower emissions.

This thoroughly "massaged" engine is mated to an electronically controlled ZF gearbox. Its electronic control unit continuously "talks" with the engine's control unit. In fact, a new Controller Area Network operates at 500,000 baud (compare that to your PC's modem!), so the two control units can compare their operating parameters. Among the benefits are smoother shifts, faster warmups and greater responsiveness.

4ETC

A significant enhancement to Land Rover's world-renowned permanent four-wheel-drive system is the new four-wheel Electronic Traction Control (4ETC). This system adds sophisticated and high-speed electronic control to each individual wheel.

Start with just one axle. If the right wheel begins to spin at a faster rate than the left wheel (determined by the ABS wheel-speed sensor), 4ETC "pulses" the brake on the faster-spinning wheel. This not only slows down the wheel so it can get a better grip, it also allows power to flow across the axle to the slower-running wheel. It all happens in seconds and it's totally automatic.

Now picture this on all four wheels. The 4ETC system is continuously monitoring the speed of each wheel and comparing the values. It also compares front-to-rear wheel speeds. It's like having a highly sophisticated limited-slip device on each of the three differentials.

The system is fully operational in all gears, including Low and High Range, and functions up to speeds of 62 mph. Above that speed, the basic three-differential set-up does the work. (It is important to note that 4ETC is disabled if the driver applies the brakes.)

ACE

Active Cornering Enhancement (ACE) is a unique Discovery Series II option (the first automotive application ever) that automatically adjusts special two-piece anti-sway bars during cornering. Normal sway bars limit body lean in curves by restricting the overall movement of suspension components. Make the sway bars too thick, however, and you increase the harshness of the ride over bumps and, equally important to Land Rover, you limit the ability of the axles to "articulate" -- travel in opposite tilt relative to each other and the vehicle. The two goals, reduced body lean on-road and plenty of axle articulation off-road, are definitely counter to each other.

ACE, however, achieves both goals by actively varying the effects of the sway bars depending upon vehicle speed and lateral "g" acceleration (cornering load). Two accelerometers, one mounted in the headliner and the other near the floor, detect cornering forces before the body begins to lean, making the system truly active, not reactive. These sensors instruct the ACE computer to apply hydraulic pressure to a set of actuators, one on each sway bar. These actuators apply torque to the sway bars, giving them added ability to "push back" (or "pull down") against body lean. It all happens in a flash. ACE can build up sufficient hydraulic pressure to counteract 1.0 g of lateral acceleration in just 130 microseconds.

The system is designed to virtually eliminate body lean up to about .40 g lateral acceleration. Above that value, body lean is progressively allowed in order to give the driver positive feedback on the vehicle's handling. This results in dramatic stability in corners, a definite benefit to driver control...and passenger comfort. It also aids steering response since the vehicle's body is kept more level to the road.

Off-road, the system goes into a different mode. At speeds below about 25 mph the same accelerometers are used to detect side tilts, and the system "locks" (there is no ACE assistance) to enable the vehicle to maintain a consistent attitude, parallel to the ground.

Individually or together, the "Thor" engine enhancements, four-wheel traction control, Hill Descent Control and ACE system yield significant benefits in a wide variety of driving situations. Put simply, they give the Discovery Series II the same prowess on-road as it is already famous for off-road.