Who's your Daddy?: How the world's most luxurious and expensive SUV was nurtured by three parents — and turned out to be so good - New Vehicles/2003 Range Rover

Don Sherman

What's the secret to building a luxury SUV capable of crawling over the pretenders to the very top of the off-road hill without soiling its formal attire? In David Sneath's case, the answer is endurance. Sneath is the chief engineer of Land Rover's 2003 Range Rover and the man who suffered:

* Consternation when Land Rover became part of the BMW Group in 1994;

* Rejection when BMW's product guru Wolfgang Reitzle vetoed his plan to upgrade the existing second-generation Range Rover in 1995;

* Elation when the Germans authorized a clean-sheet approach to the third-generation model in 1996;

* Frustration in convincing the Germans that a spin-off of BMW's X5 SUV wasn't the appropriate recipient of Land Rover's painstakingly nurtured DNA, and,

* Utter amazement to see Reitzle leave BMW then foster the sale of land Rover to his new firm Ford.

Through at all, Sneath held his ground to make sure this child of too many parents survived the birthing process to be a true Range Rover, a machine just as comfortable cruising at 100 mph as it was crawling over boulders at a walking pace. The fact that such a dual personality was achieved with hardware that seems far more BMW-like than any previous Solihull-built product is the ultimate proof of Sneath's persistence.

"Visual Superiority"

Historically, Land Rovers have sturdy steel-rail backbones, floppy bodies, stubbornly rigid axles, and powertrains with a lineage back to King Arthur's court. BMW wanted none of that and, as it turns out, Sneath agreed that a step change in the blueprints was a prerequisite to achieving his ambitious on- and off-road performance goals. So what emerged is, for all intents, an eleven-tenths, second-generation X5 that surpasses BMW's previous best in the SUV realm.

Understanding the fundamental virtues of both BMW'S X5 and Mercedes-Benz's M-Class SUVs was crucial to Reitzle's desire to create a truly superior Land Rover flagship. Balancing on- and off-road capabilities was certainly an ambitious challenge. But what this product also needed, reckoned Reitzle, was presence - a visual superiority. So the new model is purposely a size larger than its predecessor. Riding on a 113.4-inch wheelbase (larger by 5.3-inches), it's longer by 9.3 inches, wider by 2.6 inches (not counting door mirrors), and taller by 1.8 inches. Slotted neatly in size between the Ford Explorer and a Lincoln Navigator, the new Range Rover is more substantial but not too ungainly to thrive off-road.

Steel-Aluminum Stiffness

Land Rover engineers waved goodbye to body-on-frame construction while meeting ambitious targets for wheel travel, approach and departure angles, and ground clearance. They claim their structure is both the stiffest and the largest unibody in production anywhere, with a torsional stiffness of 24,000 pounds-feet-per degree and a first-order bending-mode natural frequency of 28 Hertz. High-strength steel was used to triple the stiffness of the outgoing model while providing 7,000 pounds of trailer-towing capacity and an ability to withstand 12,000-pound snatch-recovery loads (punishment applied when a recovery vehicle breaks Mother Nature's mulish grip with momentum transferred via a nylon tow strap).

To minimize the weight gains inevitable with a larger, more powerful, and more sophisticated model, Land Rover engineers used aluminum extensively. The inner and outer hood panels formed in-house are allegedly the auto industry's largest aluminum stampings. The doors are a collection of die-castings, stretch-bent extrusions, and aluminum stampings bonded with epoxy structural adhesive in a Dura Automotive Systems satellite facility. The front fenders are also aluminum. A total mass savings of 110 pounds is attributable to the use of aluminum instead of steel. The net weight gain over the retired Range Rover is approximately 500 pounds.

Underneath, at first glance the strut-type front suspension and multi-link independent rear axle look like pages from BMW's standard play book. Closer inspection reveals significant refinements in line with Land Rover's finely-bred DNA. For example, BMW and other makers have adopted aluminum suspension components verboten at Land Rover because of fears they are susceptible to cracks and breakage in cruel, rock-infested off-road environments. For that reason, low-hanging control arms remain robust steel forgings or fabrications. Air suspension is retained, albeit a new system with added sophistication (see sidebar).

Foundation brakes have BMW-supplied vented front and solid rear brake rotors and ContiTeves calipers. The power-assisted rackand-pinion steering gear is a ZF speed-sensitive Servotronic unit

Major Powertrain Changes

BMW was obviously light years ahead of the pushrod V-S Land Rover requisitioned from GM in the 1960s. The 44-liter dohc V-S under the '03 Range Rover's hood is the same basic engine powering BMW's current 5-Series sedan and X5 SUV. It has a few pertinent changes to satisfy the Brit's penchant for off-road ruggedness. The air intake is raised to thwart water ingestion in the fording mode. A new oil sump meets LR's requirement for maintaining oil pressure on 35-degree side slopes and 45-degree grades. Various seals have been upgraded from BMW's specifications to inhibit dust intrusion. The drive-by-wire throttle system has two modes - normal for on-road use, augmented by a slowerresponding calibration for creeping off-road.

The ZF 5HP-24 electronically controlled 5-speed automatic transmission features regular and sport modes as well as BMW's Steptronic manual-control capability. The New Venture Gear transfer case is a two-speed design with a 2.7:1 multiplication ratio in low range. Shifted into its lowest gears, the new Range Rover creeps along at only 2.4 mph per 1,000 rpm -- the lowest drive ratio available in any SUV this side of the Hummer. A synchromesh feature enables shifting from low to high range at speeds up to 30 mph and from high to low range below 10 mph.

In place of the viscous-type limited-slip device Range Rovers used previously, there's a Torsea center differential chosen because of its operating characteristics. This device quickly locks in the event of front-to-rear axle speed disparities prompted by a spinning wheel and it just as quickly unlocks when the brake based traction control system is active. Front and rear differentials are open and both have cast-iron housings. The front diff bolts directly to the engine's oil sump. The Bosch Dynamic Stability Control system originally engineered by BMW and refined by Land Rover integrates brake-effort distribution, ABS, traction control, yaw control, braking assist (during panic stops), and hill descent functions.

Testing and Development

Off-road driving is a rarity in Germany so Sneath and his team had to educate their BMW colleagues on exactly how tough it is to maintain a dry interior while fording 20 inches of water and surviving temperature extremes ranging from 40-degrees below zero (F) to 130-degrees above. To eliminate the home court advantage factor, the LR crew eschewed their usual Eastnor Castle off-road test venue in favor of routes through the Black Forest near the Czech border. Seventy or so BMW engineers survived the experience with a new appreciation for the glaring differences between their X5 and the indomitable Range Rover.

BMWs highly respected 5-Series sedan was selected as the role model for body-motion control and general on-road comportment To gauge driving dynamics, the combined BMW-Land Rover development team used the notorious Nurburgring race course, registering a lap time four-percent quicker than the outgoing Range Rover's quickest trip around the Eiffel mountain circuit.

The Ford Influence

By the time Ford entered the picture, the new Range Rover's launch clock was ticking. New chief engineer Jim Holland instituted a 90-day holding pattern to wrap Ford arms around the project. The team of 250 launch engineers were instructed to select the more severe standard when BMW manufacturing philosophies different from Ford procedures. Premium Automotive Group boss Wolfgang Reitzle and Ford vehicle development chief Richard Parry-Jones applied their most critical evaluation standards during final tuning stages to tone down some of the ferocity in the exhaust note and to help hone the new Range Rover's highway manners.

The new Land Rover Range Rover arrives this spring with a base price of $80,000. Will America's currently cheap gas prices help the affluent feel comfortable spending a fortune for the most luxurious on-off/roader in history? Has the mix of BMW, Land Rover, and Ford Motor Co. genes created the ultimate hybrid? These questions will soon be answered.

Range Rover's Euro-American Supply Base

BMW                                     Brake rotors
Bosch                      Dynamic Stability Control
ContiTeves                            Brake calipers
ContiTech                           Rear air springs
Delphi Automotive        Suspension strut assemblies
Dura Automotive Systems                Door assembly
Gates Rubber                     Suspension air bags
New Venture Gear                       Transfer case
Wabco                      Suspension air compressor
ZF                         Power steering, automatic
                                              trans.
Zexel Torsen                     Center differential

RELATED ARTICLE: "Cross Linking" Key to New Air Suspension

While Range Rovers have used air suspension before, the '03 model employs a new system that supports extra wheel travel (10.6 inches in front, 13.0 inches in back) and ground clearance (up 2.6 inches to 11.0 inches). The system features automatic leveling and provides four ride heights -- Access to facilitate entry and exit, Cruise for highway speeds above 60 mph, Normal for most driving, and Off-road for rock climbing and rut crawling.

The system's Wabco air compressor is nestled out of earshot in the vehicle's spare-wheel well. A new system feature is what Land Rover calls cross-linking. Solenoid-controlled valves automatically open when off-road conditions are sensed to allow inflation air to pass freely between air springs on opposite sides of each axle. Then when one wheel is forced up by uneven terrain, air passes to the opposite spring to help force the wheel down, thereby maintaining traction.

A door-mounted switch permits the driver to select the Access position in anticipation of arrival at a destination. Then, by the time the Range Rover rolls to a halt, it has already kneeled to help occupants exit gracefully.

COPYRIGHT 2002 Reed Business Information
COPYRIGHT 2002 Gale Group