Jaguar XJR-15

The Jaguar Sport XJR-15 is a mid-engined supercar produced by Jaguar Sport, a subsidiary of British automaker Jaguar and Tom Walkinshaw Racing between 1990 and 1992. Only 53 were made, each selling for US$960,165. Based mechanically on the Le Mans-winning Jaguar XJR-9, the car had an aerodynamic body designed by Tony Southgate and styled by Peter Stevens, who later went on to style the McLaren F1. The car featured in a 1-make racing series called the Jaguar Intercontinental Challenge, which supported 3 Formula 1 races (Monaco, Silverstone and Spa) in 1991. The $1m prize was won by Armin Hahne. XJR-15 was the World's first fully carbon-fibre road-car.

History

Tom Walkinshaw conceived the concept in 1988, following Jaguar's success at Le Mans, enlisting Peter Stevens to develop a road-going version of the XJR-9, originally designated as R-9R. A number of wealthy racing enthusiasts were keen to own such a car and pressed Walkinshaw into manufacturing a 'road going racer'. Original owners included Derek Warwick, Bob Wollek, Vern Schuppan, Matt Aitken, Andy Evans and the Sultan of Brunei.

In order to adapt the XJR-9 for road use, Stevens made a number of modifications to increase space and improve access. "Taking the race car as a base, we widened the cockpit by 75mm and raised the roof by 40mm to allow more headroom" he said, when interviewed in 1991. "The scale model was ready by Easter 1989, from there we went to clay...which was finished by October (1989). The first prototype was held up by Le Mans preparations but it was ready for Tom (Walkinshaw) to drive when he came back from France in July 1990."

TWR explicitly developed the XJR-15 as a road-going racing car, in the mould of the Jaguar C and D types, the Ford GT40 and the Ferrari 250 GTO. As such, the car complied with British construction and use regulations and could be registered by the owner for road-use in the UK, although with such a limited production run, the car was never type approved.

The car's production was announced in a press release on November 15, 1990 with an official launch at Silverstone early in 1991. XJR-15 was built by Jaguar Sport in Bloxham Oxfordshire (a subsidiary of TWR) England from 1990 to 1992.

Design

The mid-engine, rear-wheel drive sports car is powered by a 450 hp (336 kW), naturally aspirated 24-valve V12 engine of 5993 cc, with a Group C bottom-end and Group A top-end. The engine features an advanced electronically managed fuel injection system with a very advanced (for its time) 'fly by wire' throttle. Transmission is via a TWR 6-speed manual, unsynchronized transmission (a 5-speed, synchromesh transmission was also available as an optional extra). The XJR-15's chassis and bodywork are composed of carbon fibre and Kevlar (XJR-15 was the first road-going car built entirely of Carbon and Kevlar composites, before the McLaren F1 used similar techniques in 1993). It was designed to comply with 1990 Group C regulations, being 480 cm long, 190 cm wide and 110 cm high. At 1050 kg, the XJR-15 weighed about the same as a contemporary VW Golf. Suspension is fully independent, with non-adjustable Bilstein shock absorbers all round. Front suspension is by wide-based wishbones, working push-rods to spring damper units mounted horizontally across the centre of the car. TWR racing practice is also followed at the rear, with vertical coil-springs mounted in units with uprights within the rear wheels, allowing for the maximum possible venturi tunnels. The engine forms a stressed member for the rear-frame. The bottom of the car is completely flat, in line with Group C practice.

Steel disc brakes are fitted, with powerful AP four-pot callipers.

The XJR-15 has a 0–60 mph time of 3.9 seconds and a (gearing limited) top speed of 191 mph (307 km/h).

Although marketed as a racer, the car had been developed as a "road-going-racer" and as such, the ride height was somewhat higher than required to take full advantage of under-body aerodynamics. Additionally, the suspension was softer than would be found on the XJR-9 racer and - in a last-minute deal - Tom Walkinshaw switched tyre suppliers from Goodyear to Bridgestone just before the race series started. When interviewed by Autosport in 2011, Ian Flux recalled: "The worst thing was that Tom had done a deal with Bridgestone. At first, it was going to be on road tyres, but then they changed to slicks and wets. The fronts weren't a problem, but they didn't have moulds for the rears, so used F40 moulds instead. They went off very quickly and it was hard to judge how hard to push."

As Tiff Needell, who road-tested a development car at Silverstone early in 1991, put it: "the result is oversteer". However, once accustomed to the characteristics, he went on: "Through the very tight chicane, the XJR-15 showed excellent change of direction and I was able to pick up power early for the long right hander leading up to Beckett's. This gradually became a long right-hand power slide as my confidence increased." Users of the car as a racer in later years would lower the suspension, fit a larger wing and proper tyres to restore race-car dynamics.

As a road-car, the suspension was more softly set-up and with the right tyres, testers were unanimous in their praise. Ian Kuah, writing in World Sports Cars in 1992:"Considering its racing pedigree, ride quality is pretty good - at low speeds, better than a Ferrari 348...Levels of grip are far beyond those transgressed by any sane man, except perhaps when exiting a tight corner in a low gear when the sheer grunt pushing you through can persuade the huge Bridgestones to relinquish some grip. Seat of the pants feel and communication is terrific and the steering nicely weighted so that smooth inputs are easy. When it comes to stopping, the huge AP Racing brakes - with softer pads for road use - wash off speed with steely determination."

Ron Grable, the racing driver, writing in Motor Trend in May 1992: "As the engine sprang into a muted rumbling idle, it was impossible to keep from grinning. Easing the unsynchronised six-speed into gear, I accelerated onto the straight. Many race cars are diabolical to get moving...not so the Jag, the smooth V-12 pulled cleanly away, nearly as docile as a street-car. On the track, the XJR-15 is a truly wonderful ride, the perfect compromise between racing and street. You can say the savage edge of a pure race car has been softened slightly, or conversely, that it's the best handling street car you can imagine. Being 100% composite, it's so light that every aspect of performance is enhanced. Relatively low spring and roll rates are enough to keep it stable in pitch and roll, as well as deliver a high level of ride compliance. The brakes are phenomenal and the acceleration fierce. And always, there's that V-12, a medley of mechanical noises superimposed over the raucous rise and fall of the exhaust."

The XJR-15 offers little in the way of practicality. Entry to the car, over a wide sill, requires the driver to step onto the driving seat. The gear-lever is mounted on the right-hand side of the driver (all cars are right-hand-drive), while the driver and passenger seat are extremely close together - almost central in the car. There is little in the way of sound insulation, so an in-car head-set system is fitted. There is virtually no storage space. However, considering the purpose for which it was intended, the interior was highly praised in contemporary road reports. Ron Grable again: "Aesthetically, the XJR-15's interior is breathtaking. Expanses of shiny black carbon fibre woven with yellow Kevlar are everywhere, all fitting together with meticulous precision. Instrumentation is detailed and legibly analogue. The shift leaver is less than 3 inches from the small steering wheel, and the motion between gears is almost imperceptible. The reclined seating position provides excellent forward visibility - over the top of the instrument panel you see only racetrack."

Racing history

According to a press release by Jaguar Sport, XJR-15 was built specifically with the 1991 Jaguar Sport Intercontinental Challenge in mind: a three-race competition held throughout the year as support events for the 1991 Formula One Grand Prix at Monaco, Silverstone, and Spa-Francorchamps.

Sixteen XJR-15s were entered in each of the events. The winner of the third and final race, Armin Hahne, was awarded a cash prize of US$1 million.

As Phil Charnock recalls: "Derek Warwick won the first round in Monte Carlo (Monaco) by a mere seven tenths of a second from David Brabham after a smashing debut for the XJR-15s – in more ways than one. Despite the ever-present barriers Monaco’s mishaps were mild compared to the thrills that were to follow around the sweeps of Silverstone. Juan Manuel Fangio II took the laurels exactly forty five years after his famous uncle took his last race win around the airfield venue, but the younger Argentine’s win came only after 11 of the 16 cars were damaged in a bruising encounter.

For the third and final round at Spa where the championship’s $1 million prize was to be settled, the organisers decided that this already astounding event needed further spice, so they announced that nobody would know when the chequered flag would fall! This was due to dastardly drivers making deals to ensure they could take the prize money together. Eventually it was to end after 11 laps and several crashes with Armin Hahne surviving to take the big prize with his first win of the miniature season. Cor Euser started out on pole, holding the lead until lap eight when he had a wobble through Eau Rouge that allowed Hahne to pounce. Warwick also tried to take Euser as the English Grand Prix veteran was in contention for the big prize, but he was to find himself in the barriers. It was a fate shared by others as John Watson collected Tiff Needell and Thierry Tassin ended up on top of a wall after a brush with TWR regular Win Percy. After two fifth places in the previous encounters Armin Hahne scooped the million with a win at Spa."

When interviewed by Autosport in February 2012 for 'Race of Your Life', Armin Hahne chose his XJR-15 win at Spa as career-highlight: "I qualified second to Warwick in Monaco but half-spun on oil while chasing him, so fell to fifth. At Silverstone I had a misfire and again finished fifth. At Spa, I managed to qualify second without using both sets of new Bridgestone slicks. I found a time good enough for the front row with my 'scrubbed' first set. At the start, I followed poleman Cor Euser for a few laps, but his tyres went off as he'd used them for the second qualifying session. I passed him - it was quite easy really. The race lasted 11 laps and I won by 3-4 seconds to collect the $1m prize."