#Jaguar XKR “Badcat”

[diabolus1exmachina]

Jaguar XKR “Badcat” 

Launched in 1996 and always more of a grand tourer than an out-and-out sports car, the Jaguar XK8 shared its chassis with the Aston Martin DB7, making it the thinking man’s choice for anyone in the market for a powerful, rear-wheel-drive luxury sports car.

Whilst those figures might be impressive for the XKR; it wasn't quite enough for our petrolhead vendor Graham, who in 2007 embarked on a 13-year journey to improve and modify the once standard 1998 XKR into this stunning 632hp unique Jaguar, more commonly known as the ‘Badcat’

The Badcat started life as a 1998 Jaguar XKR, which Graham saw for sale in 2007 and having a soft spot for the X100, plus having been looking for a car for a while, this was snapped up straight away. Driving the car for a few weeks was enjoyable, but as with any petrolhead, it wasn’t long before Graham started looking into tuning options for the XKR.

This started with a smaller top pulley and larger bottom pulley fitted to the supercharger, and this was complemented with a Racing Green ECU piggy back upgrade to keep on top of the fueling due to the faster spinning supercharger. The result was 456hp, an impressive 64bhp gain from the standard bhp.

With the 4.0 litre pushed to its limits, Graham was on the lookout to further improve the performance of the XKR, and this was the start of taking the car to an entirely new level. Graham found a new Range Rover 4.4 litre V8 which became the next base for the project. The engine was rebuilt using stronger high spec’ bespoke forged pistons from German automotive parts manufacturer Capricorn, which kicked off the need to have parts purpose made rather than buying off the shelf items.

The upgrade to the 4.4 litre brought the power up to an impressive 480bhp; it was never quite enough, and the need for more power continued. This need was realised when in 2012 when Graham, assisted by Jaguar expert Tom Lenthall, found an uprated Eaton supercharger which was originally destined for an XKR GT3 racing car. This was fitted along with some other improvements to bring the XKR to 510hp.

In 2016 whilst on a track day at Goodwood, flying at over 140 mph, the 4.4 litre detonated, melting five out of the eight pistons. The cause was put down to poor fuel pick-up from the standard Jaguar tank, which would later be resolved with a bespoke designed, foam-filled ally fuel tank with swirlpot fabricated by CKL Racing, containing two Walbro 450 high-pressure fuel pumps. Only one of the pumps is needed and more than capable of providing enough fuel for spirited driving; the other pump was simply fitted as a backup. Luckily the cylinder block suffered only minor scoring and was sent off to be rebuilt at performance engine experts Classic and new forged pistons from JE in America. This gave Graham the opportunity to develop even more power, and with a freshly built engine, a new twin-screw supercharger, a Whipple W175AX, was sourced from the USA. Although being told it would not fit by the company director, Graham had other ideas. With some well calculated CAD drawing and CNC machining, the charger was made to fit, pushing the XKR to the enormous power it now produces.