Range Rover Sport switches to aluminum Premium Lightweight Architecture

  • 01-Apr-2013 01:20 EDT

The 2014 Range Rover Sport's sleek styling hints at its newfound on-road dynamic qualities.

Until now, Range Rover's line of rear-drive based vehicles has been differentiated by the use of different platforms as well as by size and price. But with the introduction of the Range Rover Sport, Land Rover has begun the process of consolidating its bigger vehicles onto a single aluminum platform termed the Premium Lightweight Architecture.

The new Sport shares its platform with that of the 2013 Range Rover, but in a shorter length, and the company's innovative aluminum platform will soon proliferate to additional models, reported Andrew Polsinelli, General Manager of Product Planning, surely in reference to the LR4.

Counter-intuitively, although the Sport is 5.9 in (150 mm) shorter, 2.2 in (55 mm) lower, and 100 lb (45 kg) lighter than the Range Rover, the Sport offers an optional +2 third row of occasional-use seats unavailable in the larger Range Rover. This is made possible in part by the new model's extra 2.5 in (64 mm) of length and 7 in (178 mm) of wheelbase compared to the previous Sport model, said Polsinelli.

The difference is seen primarily in the additional 1 in (25 mm) of rear seat legroom and is especially pronounced in the size of the rear-door aperture for improved ingress and egress, he said. These were particular complaints about the old model that have been significantly improved for 2014.

In the Sport, the switch to the aluminum Premium Lightweight Architecture produces a 39% reduction in curb mass of the body structure, slashed by 800 lb (363 kg), and a 25% increase in torsional rigidity, according to Polsinelli. While the goal with the Range Rover was to trim the weight, the Sport, which was built on the old LR4 platform, also needed an upgrade in rigidity to be able to deliver the ride and handling characteristics expected of a vehicle bearing the Range Rover nameplate.

Although the Sport shares the Range Rover's architecture, it shares surprisingly few actual parts. The Sport is 75% unique from the Range Rover, which let engineers focus on honing its on-road high-performance characteristics, as the vehicle is being positioned against the likes of the Porsche Cayenne rather than challenging the mountain goat off-road ability of a Jeep Wrangler.

Correspondingly, suspension parts have been subtly tweaked in search of faster speeds on the race track rather than the ability to climb boulders in Moab, UT. "On-road dynamics have not historically been our forte," Polsinelli conceded.

Abetting changes to the chassis, Land Rover has applied its first torque-vectoring system to further aid changes of direction. The Bosch-supplied system applies brake pressure to inside wheels while turning to assist the Sport pointing through curves. There is a faster steering rack and smaller-diameter steering wheel too, along with a more traditional console-style shifter in place of the circular shift knob used on the Range Rover, allowing for manual gear changes.

The available all-wheel-drive systems are the same as those in the Range Rover, with a standard single-speed transfer case and an optional two-speed device. The standard system's Torsen center differential has a default torque split of 42/58 front/rear for a rear-drive feel. It can vary output to as much as 62% to the front wheels and 78% to the rear depending on conditions.

The two-speed transfer case uses an electronically controlled multiplate clutch to split the power, with a default 50/50 front/rear torque split that can vary to as much as 100% to either axle if needed. The transfer case permits shifting on the fly at speeds up to 37 mph (60 km/h) and has a gear reduction of 2.93:1 for low-speed rock crawling.

Despite the Sport's new attention to on-road dynamics, its off-road ability is also improved over the previous model, with an 11-in (279-mm) ground clearance that is 2 in (52 mm) more than before and a 33.5-in (850-mm) water fording ability that is nearly 6 in (152 mm) more.

A new GKN locking rear differential helps ensure both rear wheels turn through the worst surfaces the Sport encounters.

The Sport carries over the Range Rover's 510-hp (380-kW) 5.0-L supercharged V8 engine and debuts a new 340-hp (254-kW) supercharged 3.0-L V6 base engine. Both engines feature the ZF eight-speed automatic transmission.

The V6 is a 90-degree design derived from the V8, and thanks to the reduced curb mass, it accelerates the Sport to 60 mph (97 km/h) in 6.9 s, which is 0.3 s faster than the naturally aspirated 375-hp (280-kW) V8 accomplished in the outgoing model. The supercharged V6 and flagship supercharged V8 engine both use sixth-generation twin-vortex technology from Eaton.

An electronic sound symposer on the intake tract should minimize the tendency of 90-degree V6 engines to drone, a trait that would be unsuitable for use in a premium vehicle.

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