When Jaguar began redevelopment of the R series a few years ago, its engineers knew they couldn't just stop with the powerplant. "It was obvious when we started on the R that we needed the systems to handle its power and help it perform," said Tim Clark, Jaguar's principal technical specialist. Clark and his team also looked at radically revising the drivetrain and other systems, which work together to help keep the more powerful cars on the road. "Now, we can use this technology on all our cars."
Even though Jaguar went up to 5.0 litres from its previous 4.2L V8, the new engine is lighter, smaller and emits less carbon dioxide than the last one. It also get about the same fuel economy (optimistically claimed to be 12.5 litres per 100 kilometres combined), despite producing almost 100 more horsepower (510 hp) and putting out an astonishing 625 Nm of torque, with all of that available at 2,500 rpm. Engineers also used a "sound filter" under the bonnet to balance engine noise front to back. Intake manifold pulsations are fed to the filter and accentuated in the passenger cabin under hard acceleration. The XKR also has valves in the exhaust that open under Dynamic mode for a more aggressive roar.
The six-speed automatic gearbox has been extensively revised for 2010. Now a fully shift-by-wire affair, engineers also improved the hydraulics for faster shifting. Because of the large amount of torque at low speeds, the gearbox is now designed to lock up at low rpm, which Jaguar claims gives better performance and fuel economy.
Rather than stick with a regular mechanical differential, Jaguar went with an active, computer-controlled diff to better handle the forces going to the rear wheels. Because it uses an active clutch to control torque to the wheels, it can circumvent the traction control in many cases, which uses the brakes to control wheelspin. The diff helps to control understeer without robbing the wheels of power.
The R cars also have computer-controlled dampers that read the road's surface 100 times a second and adjust their damping rates accordingly. It can predict the roll rate based on the car's speed and steering wheel input, as well as the pitch from brake and throttle inputs, to keep the vehicle level. Because of this, Jaguar claims they improve the car's agility without compromising comfort.
These advancements were an expensive undertaking while it was under the wing of Ford. So how will Jaguar's sale to Tata last year affect research and development? "So far as we've seen, it won't be a problem at all," said Clark. "In fact, Tata is interfering with us less than Ford did. Tata just wants a business plan; now, it's up to us to follow it through." Russ Varney, the chief engineer of the XK programme, agrees. And though the recent economic downturn is affecting every car company in the world (Jaguar stopped its UK production for an extended period in December and January and let hundreds of its office staff go), Varney thinks the manufacturer can continue its innovation.
"We've been through some tough times before, so we are better placed than most companies. We had already lost a factory (in 2004) and trimmed down where we could, so we are well situated for these latest [economic] problems." He also adds that being a lower- volume, niche car maker makes Jaguar more nimble to handle changes in the economic climate. firstname.lastname@example.org