Jaguar’s stillborn XJ13 racer did not need to prove itself on the track to leave a lasting legacy in the world of motorsport. Having never progressed from the development prototype phase, the sixties machine could have so easily been forgotten, held only in the memories of those who took part in the ambitious project. Yet the V12 classic inspired a number of 12-cylinder Jags and in recent years has even returned to the automotive spotlight thanks to a number of recreations, most of which have stayed as close as possible to the original’s form in order to appease the car’s surprisingly large number of fans.
What has enabled such a relatively insignificant (compared to the highly successful Ford GT40 and Porsche 917, anyway) one-off to garner so much respect over the years? Undoubtedly the car’s beautiful Malcolm Sayer-crafted design will have helped; is there a prettier Le Mans prototype than Jaguar’s low-set, smooth-panelled 13? Best of all, it was very much a case of function rather than form, instructed by intentions for a high La Sarthe top speed, so it’s gorgeous from an engineering point of view, too.
When the first designs were penned in the early sixties, cars were surpassing 190mph along the chicane-free Mulsanne Straight, hence Jaguar’s decision to develop a 5.0-litre V12 with its banks opposed at 60 degrees. It meant the engine – in essence two straight-six XK engines using mechanical injection and sharing a common crankshaft – could be seated close to the ground, midship and beneath a low-set engine cover, pulling the car’s centre of gravity down and reducing the overall surface area.
The structure around the powerplant was cutting edge, too. The XJ13 was built using an aluminium monocoque wrapped in aluminium skin, rivetted in place for structural rigidity. Its sleek design means the 13 can look deceptively large in pictures, but in reality, the body stretched to 4,483mm – just 1mm longer than an F-Type – while the wheelbase, held within those skinny, aero-encouraged overhangs, was only 2,438mm. The prototype was said to have weighed 998kg, but more mass will likely have been shed since, with later development cars due to integrate more exotic materials.
It’s claimed that the one-off 1965 prototype produced about 510hp at 7,600rpm (that sub-one-tonne mass meant it had 511hp per tonne) with 386lb ft at 6,300rpm. Drive was sent rearwards through a five-speed manual gearbox, with cogs to rival the very fastest Le Mans machines of the early to mid-sixties, including the Ferrari’s V12 275 and 250 racers. Jaguar reportedly tested the XJ13 to 161mph, but the project was culled before any more substantial runs were made. The story of the XJ13 essentially ended just as engineers were about to get into the meat of its development.
The reason related to Jaguar’s focus on selling passenger vehicles including the E-Type and then-upcoming XJ6, before investing further in motorsport. But such was the speed of evolution at Le Mans that by the time engineers were free to pick the XJ13 programme back up, it was dated technology – plus, new regulations meant the engine was too large to compete. A lot had changed in the world of sports car racing: Ferrari had since fallen from its pedestal, Ford had begun its dominance with the new GT40 and Porsche’s 917 wasn’t far off, either, leaving Jaguar with a substantial workload to bring the XJ13 up to date. Fate was then particularly cruel to the only prototype XJ13, which crashed during filming to promote the new V12 E-Type in 1971. Test driver Norman Dewis survived despite a tyre blow out at high speed on MIRA’s banked circuit, although the car was destroyed.
Jaguar did go on to repair it, but it’s lived in the firm’s museum since. That means the only way for those not connected with the original XJ13 project to experience it properly, has been to buy a replica or recreation. A surprising number have been produced in the past couple of decades, with the most recent coming from Scotland’s Ecurie Ecosse this year. But today’s Showpiece is a freshly-finished stunner from Shapecraft, which took seven-years to build and has specs pleasingly close to the original’s. Unlike some 13 replicas that have placed a body onto a ladder chassis to reduce costs, the Shapecraft XJ13 uses a monocoque and aluminium body panels, as well as a 360hp Jag 6.0-litre V12. There are modern additions, such as an Audi six-speed gearbox with a Quaife limited-slip differential, servo-assisted brakes and ECU-controlled electronic injection, but the overall ingredients are convincing ones. Naturally, it’s up for £440k, but as far as turn-key XJ13 recreations go, this has to be one of the finest.
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