Jaguar’s power units have entered legend. This month we ask whether the XF’s engine and powertrain are cut from similar cloth?
Try as I might, I’ve yet to satisfactorally reconcile the concept of a compression ignition Jaguar. But commercial realities make for expedient bedfellows and the Ford/PSA-developed 2179 cc 16 valve diesel unit powering our XF has been responsible for the marque’s growing acceptance in the vital company user-chooser market in the UK. Commercial success notwithstanding, there’ll be few obituaries now it’s been consigned to history by JLR’s new generation of ‘Ingenium’ engines. Like most of its breed, it’s an agricultural sounding device; peak power of 188 bhp and a torque figure of 332 lbs/ft at 2000 rpm going some way to mitigate against its more obvious aural deficiencies.
The problem for the XF of course has always been weight. Originally schemed on a modified version of the XJ’s X350 aluminium architecture, Ford vetoed the expense and time to market, opting instead to retain the dated and heavy DEW98 platform inherited from the S-Type. Extensively modified for XF, it nevertheless weighs a portly 1745 kg in 2.2d form. It wasn’t until X250’s midlife facelift that Jaguar managed to obtain the resources to bring the 2.2d XF to market, but for it to have any chance against its mainstream German rivals, a competitive co2 figure was going to be vital. It’s clear the quoted figure of 149 g/km was hard-won.
Jaguar engineers went to a good deal of trouble to isolate the XF’s occupants from the worst excesses of noise and vibration, giving the XF a double layer bulkhead, extra sound deadening material around the turbochargers, alternator and starter motor, in addition to active engine mounts, but taken collectively, the job of containing the engine’s NVH is a thorough one. The result of these efforts is a commendably quiet cabin. The sound of the engine is audible – (how could it not be) – but at moderate speeds it’s distant and muted. Of vibration, there is little. Stray however into the upper reaches of the engine’s power band and the engine vocally betrays its origins.
With power outputs such as those quoted here, there should be little shortage of power or torque, and sure enough there isn’t. Car magazine obtained a top speed of 140 mph and a zero to sixty time of 8.5 seconds when they tested a similar example in 2012. Obtaining it however, isn’t always as immediate as you’d like, thanks to a sometimes soporific interface between the powerplant and the otherwise excellent ZF 8-speed automatic transmission. The upshot being the XF seems to draw breath before responding to sudden accelerative inputs which can inhibit quick getaways or gaps that open up in traffic.
Gearshifts are for the most part seamless, but the manner in which the transmission software has been set up means it habitually defaults to the upper ratios, which at urban speeds means the engine often feels and sounds laboured and soporific. This need to always be in the tallest possible ratio aids economy but also means the XF often feels ‘unsettled’.
Putting the gearbox into ‘sport’ mode obviates the problem to some extent – the ZF box holding on to the intermediate gears longer and offering the driver full manual control via the wheel mounted paddles – unpleasant plastic levers that offer little tactile reward, but work well enough. The downside of this of course is not only that you hear more of the engine’s vocal, but you also use more fuel. However, I’d willingly sacrifice a few mpg for more control over the gearbox. Sport is fine when you’re in the mood, but most of the time you just want to waft.
All this aside however, the XF remains a pleasant means in which to travel by road. Jaguar have made the best job they could of masking the engine installation’s inherent deficiencies, and despite the annoyances of the gearing and the diesel’s drone, the 2.2d makes a lot of sense, while giving its 3.0 litre V6 derivative a run for its money, both in performance and economy. I can’t help feeling however, the latter would offer a somewhat richer experience.