Twelfth knight

Although both BMW and Mercedes now produce 12-cylinder engines, they are comparative newcomers to the art.

The establishment? Try Jaguar.

The alloy, 272 bhp 5.3 V12 first appeared in the Series III E-type V12, of which 7990 convertible examples and almost as many coupes were sold.

The 12-cylinder was always intended for the Jaguar XJ saloons and it duly made the transition to the Series I in 1972. It wasn’t a heavenly union, however, for only 4113 cars were built and it disappeared one year later, when the Series II XJ arrived. Now Jaguar really got into its stride, then unopposed by the Germans (BMW went into the V12 business with the 750 in 1986, and Mercedes didn’t follow suit until two years ago). The V12 accounted for nearly 20 per cent of all Series II sales. From 1973-79, some 22,606 units were sold; the durable Series III was even more prolific.

In the past 20 years, Jaguar has sold over 50,000 V12 saloons in total, though the Series III had no more than a token presence by the time the latest generation of XJ saloons was launched in 1986. Perhaps typically, as the foreign opposition was gearing up to enter the fray, the British were getting ready to pull out. The Series IV XJ was never designed to take the V12…

Now, the Coventry company is (belatedly) back in the mass-production V12 saloon sector. To mark that return, a six-litre version of the aluminium unit transforms the performance, and price, of Jaguar XJ saloon ownership. Over 300 bhp and 342 lb ft of torque sweep it into the 150 mph bracket, allows magnificent overtaking ability and drops urban fuel consumption to 12.6 mpg of 95 RON unleaded.

The price is £46,600.

I thought it was worth it.

UK range

So far as 12-cylinder Jaguar saloons are concerned, there is a choice of two: the £46,600 XJ12 includes sports suspension and wheels, and there is an equivalent Daimler Double-Six. The latter, listed at £51,700, is more luxurious, has ‘touring’ suspension and smaller (in diameter and width) alloy wheels. Daimler compensations are standard Autolux leather, six-disc CD player and colour-keyed interior items such as the gear knob, selector surround and handbrake grip.

If you prefer your Jaguar V12 in two-plus-two coupé (£45,100) or convertible (£52,900), there is the recently updated XJS (road impressions next month), which now also shares the six-litre unit.

Frankly, I found that the latest XJS appeals more than ever, its Bilstein dampers making it a surprisingly agile performer on sodden lanes. Unfortunately, the test schedule was too advanced for us to arrange a swap… Also, the reintroduction of a Jaguar 12-cylinder saloon is more pertinent than the enlargement of said XJS, which has deployed the V12 in a variety of specifications since 1975.

Technical analysis

There are specialists who offer Jaguar V12s stretched all the way to eight litres, and TWR has been a regular user of seven (for racing) and six (for road use) for some years. This production unit has most in common (including power output) with the six-litre version previously used in the 187 examples of the JaguarSport XJR-S sold in Europe last year (80 of them in Britain).

The expansion from 5345 to 5994 cc is achieved with a longer stroke (up to 78.5mm from the original 70mm). Compression is the same as the JaguarSport unit, at 11:1, but lower than that on the last 5.3 litre production V12s. May combustion chamber principles (originally defined by the HE badge) remain in use, and compression is naturally down in these catalytically converted days.

Jaguar reports a 22 per cent power increase as a result of this capacity enlargement. It now amounts to a thumping 318 bhp at 5400 rpm. Maximum torque is augmented by a hefty 23 per cent (342 lb ft/3750 rpm), and this is the most notable aspect on public roads.

There have been other significant changes, including the use of a unique Lucas-Marelli injection and ignition, low loss catalyst system, twin fuel pumps within the fuel tanks and hydraulic engine mounts.

The engine installation leaves little spare room, yet electric fans do squeeze in front of the large radiator. Rather busily, they remind you of their presence with the same, slow-speed frequency as that needed to cool a turbocharged car.

The tachometer redline drops 500 rpm, to 6000, but even this is fairly healthy: those specialist 8.0s were restricted to just 4500…

The underbonnet appearance has been tidied considerably, a central panel covering the straggle of wires and leads that used to daunt and depress any casual interloper. Other changes to front-end engineering demanded a reported £35M. New features include installation of a front crossbeam (not present on six cylinders), whilst all models now share a ZF rack-and-pinion steering system that has forever banished the old ‘featherlight and fingertip’ control days, demanding firm inputs from the driver and returning increased satisfaction-per-mile.

The Jaguar’s standard sports suspension kit is less stiff than some seen on JaguarSport models, but is firmer than anything previously offered on a production car.

If you are an incurable amnesiac, a boot lid badge and a gold ‘V12’ reminder on the glove box provide further opportunities to revel in your pole position status.

Action

Initial impressions of K163 GHP were dominated by its imposing presence. It doesn’t have the sheer bulk of the Bentley Turbo R of our recent acquaintance. It opens the door to a lower, more streamlined kind of powerful, prestige motoring, its purposeful stance emphasised by bulging wheels and tyres which cram almost inadequate wheel arches.

The metallic finish and interior workmanship were excellent.

The opulence of restrained grey leather within was particularly finely worked around the side rear windows. The only blots on an otherwise classy, elegant status symbol were the tacky exterior side stripes.

The cabin positively glitters, wooden panels being surrounded in gold and chrome dripping everywhere from ashtray to door-handle: not to my taste, but all beautifully executed. Gold is also applied to grille (although the vanes are sprayed in black) and wheel badges.

You sit low in a Jaguar, encapsulated by 4000 lbs worth of coachwork, but the company is still struggling to come to terms with the best of modern ergonomics. The green digital display contrasts oddly with the classy, black and white six-dial instrumentation, whilst the standard trip computer is a nightmare to actuate accurately on the move, its keypad obscured by the four-spoke steering wheel and the bulk of its standard fitment air bag (only the driver is thus protected, at present).

The heating and ventilation system (with standard and effective air conditioning) proved one of the best of its kind, but the British ‘summer’ was notable for cool temperatures and the heavy rainfall that characterises Bank Holidays in this country.

Not so impressive were the plethora of seat adjustment controls poked along either side of the transmission tunnel; these are hard to see and potentially dangerous, should Jaguar relaxation leave driver’s or passenger’s legs lolling up against the three-way buttons. The test car had optional seat warmers (£350) and an ultrasonic security system (£190).

The automatic transmission lever works logically, but through elongated movements. Jaguar provides a dual J-pattern gate offering a choice of simple automatic operation or manual selection of everything bar first gear. The latter is very handy should you need to slip down a gear on inclines or winding tarmac, thus preserving the huge disc brakes against the ravages of restraining 150 mph performance in nearly two tons of motor car.

And it does perform.

It now has far more to do with driving and less with feather pillows. Compared with its predecessor, Jaguar reports top speed up 16 mph to a majestic 155, whilst the 0-60 sprint is slashed from the stately Series III’s 8.9 seconds to just 6.8.

However, improvement in mid-range response will be the most popular feature for most owners. It allows you to slip along without irritation to other road users, such is its ability to overtake safely and swiftly in a shorter time than it took before.

According to Jaguar, it now takes around 0.8s less than it once did to get from 50-70 mph in kickdown, and there are even greater chunks of time to be saved higher up the performance plane. For instance, 90-110 mph occupies 6.6s (rather than 8.3). and 110-130 mph takes 10.5s (as opposed to 13.9).

The price you pay at the fuel pumps is down, according to Jaguar calculations at least, its composite consumption for the new V12 equating to 18.4 mpg (the Series III returned 17.9). After 535 miles, we had been thirsting along at just 14.5 mpg, which is comparable to Jaguar’s anticipated urban consumption.

From a purely subjective point of view, based on experience of the six-litre engine in both saloon and XJS applications, I felt sure that some of the 5.3-litre’s smoothness has been lost. Between 1500-5000 rpm, the band most customers will explore, the trade-off is welcome extra performance and response, but beyond 5000 revs the engine definitely sounds hoarse in comparison to the original, smaller unit. Today’s V12 is not quite the suave servant it was, fulfilling a gruffer, more aggressive, role than before. It is not a major criticism, as we think it still compares well with BMW and Mercedes-Benz, but when it comes to demanding absolute standards of civility it could be worth driving the Merc and the Jaguar back-to-back.

The steering, ride and handling traits are totally unlike its predecessors. Jaguar had taken many steps along the way to a more direct feedback from the Adwest power assisted system, including deleting a tooth here and there from the rack. Now it has gone the whole hog and specified a ZF system. Speaking patriotically, that is a blow, but I prefer the German system. You have no doubt what the car is doing and you are connected in way that simply was not in evidence before. Efforts at the rim are increased, but if this is a problem you shouldn’t be on the road in the first place…

As for the ride and handling, Jaguar may have gone too far for the bulk of its customers. The ride does deteriorate below 35 mph on rougher surfaces; one 30 year old enthusiast said that it was a bit stiff for him. I found the grip and composure extremely impressive, and once you get above town speeds the ride is immediately back in the Citroën class. Despite its inadequacies below 35 mph, it was still as good as many German aspirant saloons and much better than the Bentley Turbo R. Still, it’s a long way from the padded luxury traditional Jaguar customers may expect.

It will be interesting to see what percentage opt for the Daimler’s ‘touring’ settings, although even that will not be an entirely fair guide; most people tend to take what they are offered in the showroom.

Verdict

After recent stints in Bentley and AMG Mercedes-Benz, plus personal experience of the new Mercedes S-class on road (for a week) and track, not to mention assorted mileage in both Mercedes and BMW V12s (the latter only in 300 bhp trim, not the latest, enlarged 850CSi guise), I still find that Jaguar’s blend of value-for-money, luxury and charisma retains a strong appeal.

The XJ saloon has some annoying detail cabin faults and the lines are not as elegant as many of its forebears, but it is much better built than before. The Jaguar XJ12 provides a unique cocktail of comfort and power. The six-litre represents major mechanical progress whilst a replacement, more graceful Jaguar body is readied for the mid-1990s. J W