What is it?
Here’s Jaguar’s luxury express, the XJR, fresh from a 25bhp power boost that forms the sole performance tweak imparted upon the 2018 Jaguar XJ line-up.
Following a left-hook drive in the aspirational climes of sun-drenched Portugal, we’re now sampling the XJR 575 (as in 575PS, or 567bhp) in right-hand-drive form in the more pragmatic context of a slushy December morning near Slough.
As a refresher, the XJ engine line-up includes two 3.0-litre V6s: a 296bhp diesel and 335bhp petrol, both of which can be had in standard-wheelbase or long-wheelbase form, the latter with an extra 125mm between its axles. Then there are two versions of the evergreen range-topper, the 5.0-litre V8 with a twin-vortex supercharger: the 503bhp LWB Autobiography and the SWB 575 we’re driving today.
All models use 8HP-series eight-speed torque converter automatic gearboxes from ZF and are only available with rear-wheel drive in the home market.
In addition to the extra, ECU-liberated grunt, the 575 is differentiated from the previous XJR by the likes of special kick-plates, diamond-stitched leather upholstery and ‘575’ badges inside and out.
What's it like?
Alumni of early 1990s video gaming may recall a ripping piece of work by Bitmap Brothers called ‘Speedball 2: Brutal Deluxe’. The latter two words sum the XJR 575 up nicely. Few would have bemoaned the previous XJR’s pace, managing 0-60mph in 4.4sec with an electronically limited 174mph top speed, but the 575 cuts 0.2sec and adds 12mph to those respective figures, yet still provides a ritzy interior and impressive comfort.
The adaptively damped XJR may shuffle around on quite tatty roads, but even big ridges fail to cause significant disruption, while long-wave bumps are taken with the accomplished nonchalance that you’d hope for from a 5130mm-long limo.
The steering is even more polished. Electrically assisted since 2015, the tiller is slick but suitably heavy for a car of this size and even provides decent road feel, yet is reassuringly settled at a cruise. Turn-in isn’t razor sharp but still usefully swift, while body roll is very tidily curbed, surely thanks in part to the car's half-sensible, sub-1900kg kerb weight.
In a turbocharged age, the XJR’s supercharged V8 is a real indulgence, for its ready throttle response as much as its generous power band that extends from 2750rpm to the 6500rpm redline. Acceleration is enormous, but the blower makes power delivery predictable, too, which is a blessing on today’s cold, wet Tarmac, on which the rear tyres regularly scramble for traction. The soundtrack remains relatively muted, but its pleasing growl-and-whine duet majors on quality more than volume. Downshifts could come sooner after you’ve tapped the left-hand metal paddle, but upshifts happen more quickly, and the ZF ’box generally marshals the powertrain well.