Land Rover Discovery (2005-) – Car Reviews, News & Advice

4x4 Magazine
April, 2005

SOLIHULL SAVIOUR
We've already given the new Land Rover Discovery the thumbs-up when it comes to on-road performance. In the October 2004 issue of 4X4 Australia, we scooped the rest of Australia's motoring press to bring you the first on-road test of all-new Discovery 3, and now we've given it a full, off-road work-out.

Our test drive consisted of a good mix of sand driving, steep muddy descents, deep-water crossings and rocky climbs. In between the off-road sections we drove both the petrol V8 and turbo-diesel V6 models on open secondary roads and twisty alpine passes.

All of the test vehicles were air-spring-equipped, seven-seat models with the full Terrain Response package. A test of the base-spec, five-seat, coil spring, petrol V6 model will have to wait until early next year.

Although Discovery 3 retains a separate chassis for off-road strength, the live axles of the old model have been flicked in favour of a fully-independent double wishbone suspension set-up for better on-road ride and handling. That move may irk some purists, but Land Rover has ensured the Discovery 3 is a capable vehicle in the rough stuff.

Land Rover describes the Disco 3's structure as an Integrated Body-frame. Steve Haywood, chief programme engineer on the Discovery 3 says: "Its advantages over a conventional ladder-frame include lower weight and greater rigidity, which aid handling and ride, especially on the road. Its benefits over a monocoque (or unitary) body are its strength and ruggedness."

Unlike a conventional ladder-frame chassis, the Integrated Body-frame is produced using a technique known as hydroforming, where fluid pressure is used to form the complex shape of the chassis. This allows for more curvature in the chassis, and for the rear drive shafts to pass through the chassis frame to protect the shafts, lower the centre of gravity and to allow the floor of the vehicle to be flatter than if a conventional ladder-frame design was employed. Vulnerable systems, such as cables and pipes have either been located in the chassis rails or alongside them to minimise the risk of snagging off-road.

At the heart of the Disco 3's off-road package is the Terrain Response system, which has been designed to make driving the vehicle as simple as possible, as well as to increase traction. It operates via a large dial on the centre console that allows the driver to select one of five terrain settings. There are two on-road settings: a general driving programme; and a slippery roads programme (called grass/gravel/snow). And there are three off-road modes: mud and ruts; sand; and rock crawl. Once a programme has been selected, Terrain Response chooses the most appropriate settings for the vehicle's traction control, throttle response, ride height, Hill Descent Control, transmission and diff settings.

"We analysed the characteristics of nearly 50 different types of off-road surface, and determined the vehicle system inputs necessary to optimise performance on each," says Steve Haywood. "We concluded that these can be distilled into just a handful of programs – and those are the settings we offer on Terrain Response. It's like having an expert alongside you, to help you get the best out of the vehicle, whatever the conditions, on-road or off."

Terrain Response makes the Disco 3 feel extremely capable over a wide variety of terrain types. On our test drive, we intentionally selected the wrong settings for certain surfaces to measure the system's effectiveness. For example, selecting the sand setting on rocky sections increased throttle response, making it more difficult to drive smoothly. Re-engaging the rock-crawl setting dampened throttle response and made it easier to drive the vehicle smoothly over bumpy ground.

Discovery 3 also has the mechanical goods to tackle serious off-road terrain. The petrol V8 makes 220kW of power and 427Nm of torque, and is mated to a six-speed auto box with power directed to all four wheels via a transfer case with a 2.93:1 reduction in low range. This gives an impressive overall reduction in low-first gear of 45.581:1 making slow-speed trail work and steep climbs a doddle.

The V8 is a derivative of a Jaguar engine that has been heavily modified for use in the Discovery. Capacity is up from 4.2-litres to 4.4-litres, resulting in a torque improvement at lower revs, and oil capacity is up from 6.8-litres to 8.6-litres, so that oil is supplied at extreme driving angles. Oil seals are also modified to protect the engine from water, mud or slurry ingress.

While the 140kW common-rail turbo-diesel V6 can't match the V8 for power, it exceeds it for maximum torque, making a massive 445Nm at 1900rpm. This engine, too, is a derivative of a Jaguar design. Rather than a traditional cast-iron engine block, it's made from compacted graphite iron (CGI), which is stronger, stiffer and lighter. The use of CGI means that no cylinder liners are required, so the engine is more compact.

Unlike the Jag engine, which has two turbochargers, the Land Rover unit has a single KKK unit – fully sealed to prevent water ingress. The turbo employs variable nozzle turbine (VNT) technology to optimise torque across the rev range. The TDV6 meets EU3 emissions legislation and has the potential to satisfy all known future legislation.

Overall low-range first in the turbo-diesel auto is also impressive at 43.259:1. A six-speed manual box is offered with this engine as a no-cost option.

The Disco 3 features an electronically controlled centre diff lock and there's the option of a rear diff lock, also controlled automatically by Terrain Response.

Upper-spec models are equipped with an in-dash display to alert the driver of what the vehicle is doing, with information such as what Terrain Response setting has been selected, where the steering wheels are pointed, what the suspension is up to in terms of wheel travel, and when the diffs are locked or unlocked. The steering-wheel angle display is very useful when you're sliding down a slippery slope.

As well as leaving it up to Terrain Response to select ride height, the driver can manually adjust height via a toggle switch and, like the Rangie, the air springs are cross-linked: as one wheel is forced upward by the terrain, the opposing air spring is pressurised, forcing the wheel downward for better traction. Cross-linking mimics the action of a live-axle so that all four wheels remain in contact with the ground until suspension travel has been exceeded. The Disco 3 with air springs offers an impressive 255mm of wheel travel at the front and 330mm at the rear.

The air springs also offer variable spring rates for a softer or firmer ride depending on the Terrain Response setting and conditions.

So, what's the verdict off-road? Despite its independent suspension, the Discovery 3 is about as good in the rough as any other standard 4X4. Perhaps even better. Land Rover has a lot riding on this vehicle and we reckon the company's reputation as a manufacturer of capable off-roaders is safe. With the Disco 3, it may also gain a reputation as a manufacturer of great on-road vehicles.

The Integrated Body-frame structure gives Discovery 3 tremendous protection in case of impacts. Safety features include door-mounted anti-intrusion side-beams and up to eight airbags in some models. There are dual front airbags, two airbags in the front seats to provide protection for the thorax, two full-length curtain airbags above the first- and second-row seats, and two side bags in the rear seats on seven-seat models.

Land Rover is pitching Discovery 3 at the M-Class in most markets but it will take a hit on profit in Australia to regain sales volume and aim pricing directly at Toyota Prado.

The entry-level V6 petrol Discovery S, with five seats and coil springs, will squeeze below the luxury-car tax at $56,000. The top-of-the-range V8 petrol Discovery HSE will be priced at around $91,000.

The full range consists of eight models:

PACKAGING
The Discovery 3 is a much bigger vehicle than its predecessor and is one of the few off-roaders to offer seven full-size seats.

The hydroformed chassis, with its complex curved shape, allowed the designers to maximise interior space and, when the seats are folded away, gives the Disco a completely flat cargo floor all the way to the front seats.

On seven-seat models, the second- and third-row seats have individual folding arrangements for all five rear seats allowing for a wide variety of seating arrangements. Five-seat models have an asymmetrically split 65/35 second-row seat.

The third-row seats offer a decent footwell so that adults can sit comfortably without a knees-in-the-air posture. Despite the stadium-seating arrangement, offering all passengers a good forward view, there's plenty of headroom – even in the third row.

Up front, the use of an electronic handbrake, via a small switch on the console, frees up space. There's an array of stowage areas and cupholders, and upper-spec models feature a chilled box in the centre console.

All of the instruments and primary controls are well-designed and sensibly positioned. Some secondary controls, such as heater/vent controls and sound system controls, take some familiarisation before operation becomes second nature.

Access to the cargo area is made easy by a cleverly designed, horizontal and asymmetrically split tail-gate.

TERRAIN RESPONSE EXPLAINED:
Terrain Response controls a number of systems and technologies, including:

Engine-management system: the throttle map is altered, suiting torque delivery to the chosen terrain.
Electronic control system: of the auto gearbox, to optimise gear-change points.
Air suspension ride height: automatically adjusts for maximum height in the 'rock crawl' and 'mud and ruts' programmes.
Dynamic Stability Control (DSC): normally stops torque to a wheel after loss of traction, but in some off-road situations torque-feed is still desirable, even when traction is being lost. Terrain Response automatically adjusts DSC, for appropriate torque.
Electronic Traction Control, Brake-force Distribution and ABS brakes: these slip- and braking-control systems are all adjusted and tuned by Terrain Response to offer optimum grip, braking power and safety on the chosen terrain.
Hill Descent Control (HDC): automatically restricts speed downhill, using the anti-lock brakes, and enables drivers to remain in control on slippery downhill stretches. HDC is automatically engaged on all programs except 'general driving', and downhill speed rates vary depending on which surface is selected (in 'rock crawl' the lowest speed is selected to prevent vehicle damage).
Electronically controlled centre and rear differentials with different slip or locking rates for the different terrains.

Land Rover Discovery (2005-) (April 2005)