Glorious Twelve - Jaguar V12 Saloons

Enhanced power, performance, economy and refinement: these are the primary aims Jaguar set itself when it implemented the long overdue programme of changes to its V12 saloon models. And after trying the Coventry marques latest offering we have no hesitation in applauding success that we expect to manifest itself further in broadening sales appeal while clawing back ground lost to such rivals as the old Series III cars were allowed to wind down to the point where their performance had become disappointing.

The heart of the latest models is that evergreen V12, a majestic piece of engineering now stretched by Trevor Crisp and his team from the original 5340cc by enlarging the stroke from 70 to 78.5mm to yield a capacity of 5994cc. Other internal changes include revised cylinder heads, a new Lucas Marelli management system and low-loss catalyst set-up. The official power output is a quoted 318bhp at 5400rpm, with maximum torque up by a similar 23 per cent margin to 342Ib ft at 3750. “The figures are homologation levels,” admits Crisp when taxed about conservatism. “You have to file the papers early and we just kept on developing the unit.” Talk of 325bhp plus and you probably wouldn’t be too far wrong.

Originally Jaguar had no plan to build a 12-cylinder version when the XJ40 was first conceived, fearing that such engines might have had their day. Nor, initially, was there even going to be a Jaguar version once the project did get the green light. It was to be a luxurious Daimler only, suitable for wafting businessmen about. Then director of cornmunication and public affairs David Boole, and manager, product affairs, Joe Greenwell persuaded the company to do a pukka Jaguar version. It was a very prescient move.

Jaguar has reworked the engine bay for the 1993 model year, and with a special crossmember the V12 just slips into a common bodyshell.

Neither model lacks anything. The Daimler Double Six is naturally the softer-sprung as befits its role as the perfect vehicle for the chauffeur-driven. Jaguar, though, needed to tackle BMW and the like at the sporting Grand Tourer market level, and the V12 does this very competitively. If BMW’s 750 is a McLaren, the Jaguar is a Williams, similar, but redefining the parameters once again.

The V12 has always been smooth, but in six-litre guise it is better than ever. Better still, power outputs unit to unit are now more homogenous, something achieved by former chairman Bill Hayden before he handed over to Nick Scheele. Sadly, little of Jaguar’s racing experience with larger versions of the engine went into this one (six litres is, of course, small beer compared to TWR’s 8.1 or Forward Engineering’s even larger offerings), but part of its heritage are the 6.4 versions that were operational at the factory from the original V12’s birth. The engine has long needed a really modern transmission, and now that GM’s 4L80-E four-speeder replaces the same company’s 400 three-speed unit performance has been enhanced all round. Our only complaint was a slight jerkiness on part-throttle upchanges that was detectable on the first car we sampled during a recent test in Biarritz. The second was better.

Some shortcomings betray the true age of the X140 concept: the confined footwells, and the limited side glass area and relatively high waistline, but the V12 is still a grand car, and a very quick one. Aficionados will be delighted to know that all of the lost performance is back, yet delivered with such smoothness that it is easy to travel faster than you think. The V12 remains totally unruffled right up to its 6000rpm redline and that translates to a genuine 155mph. Unlike BMW’s 750i, the V12’s most immediate and highly enjoyable rival, maximum speed is not governed. Tales abound of well-loosened models that have touched 160mph. Add acceleration to 60mph in around 6.8s and to 100 under 17s and it is immediately apparent that this 4376 lb sporting saloon is very quick. Such performance places it right into Mercedes 600SEL territory, marginally quicker than the BMW, and significantly faster than the Lexus LS400, judging from Autocar & Motor figures quoted by Jaguar. Mid-range the story is the same, and we look forward to confirming them in a full road test.

As an XJ fan of long standing I have always preferred the sports suspension models, and though Jaguar has not gone to extremes on the V12, it has achieved an excellent compromise between stiffness and absorbency. The XJ12 is still a large, heavy car, as it reminds you when you initiate fast direction changes on twisty roads, but it turns in superbly and tackles all surfaces with admirable equanimity. It soaked up all the surface irregularities that we encountered without ever evoking memories of the underdamped floatiness of, for example, the standard Series I or III models. Where the Daimler relies on 7x15in cast alloy wheels shod with Pirelli’s P4000 225/65 ZR15 tyres, the Jaguar’s wheels are an inch larger in diameter and an inch wider, and are covered with Dunlop’s SP2000 225/55 ZR 16s. The XJ12 has stiffer spring/anti-rollbar rates than the Sports Pack XJ6 (88N/mm front versus 84, 89N/rnm rear versus 78), and this goes a long way towards creating the perfect ride. What is most outstanding about it, apart from the finely-limited roll and pitch, is just how well damped it all is. At no time did our car lose its poise, despite being reasonably hustled on some tight French roads. Jaguar has clearly done an excellent job further enhancing what has always been a very forgiving chassis.

It’s easy to see why company representatives are so bullish about its new models. All the old character is back, with a lot of enviable new facets, and a strong demand has already begun to build up in the showrooms. “Certainly our three-year, 60,000 mile warranty is adding a great deal to our sales at present,” says marketing director Roger Puttnam, who is equally excited about prospects in the vital US market. In the past the V12 has tended to be a little too technical for buyers weaned on pushrod V8s, but 40 per cent of V12 saloon production of 3,000 units in 1993 is headed west, with 600 scheduled for Germany, 450 the UK and 300 Japan. “We believe those figures may also be undercalled,” says Boole quietly.

In the UK the XJ6 3.2 has always been an outstanding story, priced at £26,200, but the new XJ12 looks set to rock its rivals in similar fashion at £46,600 (the Double Six is £51,700). That places it above the Lexus (£38,657) but well below the 750i (£53,250), Mercedes 500 SE (£61,800), Bentley Brooklands (£87,549), Mercedes 600 SEL (£88,600) and Rolls-Royce Silver Spirit (£95,986).