First among sequels

The XJR-6 was the car that brought Jaguar back into the endurance sportscar winning circle, after an absence of 30 years. Mark Hales gets behind the wheel

The Jaguar XJR-6 was the car that in 1986 defeated the long-established might of Porsche to give Jaguar its first International Sportscar racing victory since the 1957 Le Mans 24-hour race. And this blunt, squat machine is the very car that won the Kouros 1000km race at Silverstone 11 years ago, driven by Derek Warwick and Eddie Cheever. Although its successors would win the World Sports Prototype Championship three times for the TWR Jaguar team, racking up two wins at Le Mans in the process, this was the car that first placed Jaguar back in the winning groove. But how… What secret ingredient gave it the edge over Porsche, endurance racing’s masters?

The XJR-6’s all-enclosing bodywork with its distinctive rear spats give it the appearance of some space age suction craft. The droopy body has a multitude of wings, ducts and slots which guide air where it is needed to cool, to push down and to let the car slip along with less hindrance. But, no more or less than you’d find on the Porsche. It wasn’t as if TWR and Jaguar had hit upon a new aerodynamic advance — like Colin Chapman did for his Lotus 78 and 79 Grand Prix cars — to give them the winning margin over Porsche.

The answer is not likely to be found in the engine department either, though it certainly has the power. The 6.0-litre V12 was developed from Jaguar’s production 5.3-litre unit, with its internals revised and replaced to boost power output from 275 to more than 600bhp. Bigger, more powerful versions would follow, reaching their apogee with the 700bhp-plus 7.4 litre that powered Jaguar’s 1991 Le Mans challengers, but even the 6.0 litre of the XJR-6 was the biggest engine of the 1986 season. It needed to be, because its production car origins were revealed in the fact that it was still a stock block with one cam per bank, and there were no turbos to boost the induction, unlike the smaller but more refined power plants of the 956 and 962 Porsches.

The front and rear body sections are held with just three pins each and two men can lift them off in seconds. Revealed, the V12 looks enormous, topped with a double row of huge injection trumpets and feeding an elaborate bunch of bananas exhaust. Everything under the rear body is suitably beefy to match, but the overall appearance is clean and simple and surprisingly devoid of pipes and wires. Huge beams locate the rear suspension and rockers half the width of the car operate springs which I notice are labelled 1800lb. This is at least 50 times greater than the toughest of road cars. Then you notice the huge rear air tunnels, as close to the rear wheels as possible and sweeping up either side of the gearbox casing at the car’s centre. Each tunnel speeds the passage of air from under the car and creates a low pressure area beneath. The rear wing which is attached to the gearbox by a triangulated lattice hewn from a solid chunk of exotic aircraft spec alloy, is bigger than the average Cessna’s tailplane and adds yet more invisible weight to the 15in wide, 19in diameter rear Dunlop slicks. Side skirts stick out at the bottom of the car’s slab sides to help keep the air underneath from spilling at the edge.

A huge flat splitter sticks out in front of the nose and runs the car’s entire width, a few inches above the ground. So named because it splits the oncoming airflow, it directs enough underneath to feed the tunnels, and more upwards to the channel that runs up the car’s snout, exhausting over the roof to help feed the engine intakes and the rear wing. I think of childhood experiments holding a hand against the airstream passing the family car’s open window and begin to imagine how much sheer force will be at work here. Neatly articulated carbon fibre ducts move with the suspension and feed cooling air to the giant discs and calipers filling the magnesium front wheels. Pushrods disappear from girder-sized bottom wishbones up inside the carbon fibre chassis tub to rocker arms the thickness of your forearm. I can only imagine how tough the springs on the other end must be.

Now you begin to get some sense of the overall downforce this thing can create. The areas where air will flow, the wings and tunnels, are sure to bring pressure many times greater than a modern Grand Prix car can generate, because they are so much bigger.

Bodywork back on, the car looks smaller. There’s not so much rear overhang as there is on a Porsche 962 and this helps the sawn-off appearance. Everything is beautifully machined and neatly fabricated. The doors shut with a satisfying click, hinging open and up like a Lamborghini’s, but they need watching. The icy wind battering Silverstone slammed one shut with such force that it would have severed your hand. Clambering in is easy once you learn to stick legs across into the passenger space and lever the torso in with your hands on the roof. Then, simply slot backside into the firm bucket seat and drag the legs under the wheel. This is almost in your lap, and big by race car standards about the size of an Escort’s. There could only be one reason for that. Fighting all the downforce via 13 by 17 in front slicks must be a muscular task. A minimum of dials and switches confronts you just the essential temperatures and pressures with the all-important rev counter dead centre and visible through the wheel. Flick the three switches for ignition and fuel pumps and slide a fourth for the starter.

There are two surprises. The engine whirrs as only 12 pistons passing compression can, before gently crackling into action. It then settles into a spit-free smooth idle. Electronic engine management has certainly taught the modern racing engine some table manners. The second revelation is the thrumming you feel through the seat. A standard Jaguar V12 is one of the smoothest engines known to man and from outside, the two downward pointing unsilenced exhausts bellow forth a distinctive but smooth sounding rasp. From inside though, there’s an odd tremor passing through the car a harmonic that seems to bear no relation to the revs on the clock. You can’t hear the exhaust above the induction and mechanical noise going on inches behind you, and it sounds and feels oddly as if the engine is turning at half the speed shown on the tacho. Prod the throttle and there’s a real hint of the masses thrashing around inside.

The steering is, surprisingly, feather light. I remember the tyres are cold and still covered in residue from the car’s last outing, and at this speed the downforce is barely pressing, but it’s still a surprise. Gears too are easy and accurate. The stubby lever that leads to a gearbox way out behind the engine moves in a four-inch square, as far across as it does fore and aft, but provided you aim the lever in a general direction and don’t try to direct it, the springs in the box find the slots for you. There’s no synchro but no gnashing of teeth either and you wonder how gears so clicky and easy can handle 700 horses at one end and a gorilla on the other for 24 hours. Ratios are very long and an exploratory trip up through the sequence to fifth almost stalls the engine. Must have the Le Mans gears in, so I probably won’t need top. Clutch is light as well.

Must get the tyres clean and warm before I do anything lively. Gently extend the right foot in second gear. The rev counter flicks round together with the thrum in the bum. The tail snakes viciously. Same in third, and in fourth. Careful now. Especially as the front end is darty and nervous. The tiniest movement and the car feels as if it has stepped bodily sideways rather than obeyed a command to turn. It’s totally unnerving. How can I go fast enough to heat the tyres on this freezing day without crashing in the process? Into the newly smoothed complex at what feels like walking pace. Ease the wheel right and… it swaps ends. Not viciously, but inevitably. Nothing I did with the wheel had any effect.

Must forget that it happened. A bootful in first has the car facing forwards just as easily, then it’s off again. Accelerate as hard as I dare then brake. Squirt and slow, again and again. Ease into the corners, boot it right on the exit, let the wheels spin, heat the tyres. And thank goodness, as the laps pass, the tail gradually begins to settle, the nose becomes less neurotic, but there is still absolutely no information whatsoever from the wheel rim. It feels about as informative as you’d find on a 1970s Buick.

A quick stop to check wheel nuts, confirm that the tyres have scrubbed clean and check the pressures, and it’s time to get going. Now, as I wind it up on the straight, not only do I need fifth, but I could probably do with a taller one. The car doesn’t so much accelerate as gather speed in a relentless, long-legged fashion. There’s no frenzied series of gearshifts to suit a narrow rev band, just an inexorable force sweeping you ever faster. The speed brings some welcome extra warmth to the Dunlops and while the steering is still not exactly talkative, it has gained a little weight.

I’m working myself up to take Abbey curve flat in fourth. I’m beginning to feel the force, the invisible hand pushing down. There are bumps in Silverstone’s billiard table-smooth tarmac where I have never felt them before. And I know now that I have to trust the car. The faster you go, the more the force presses down, the more the tyres heat up, the more they grip. Forget what you think you can do and think instead what the car can do. You are now a part of the car, a constituent in the overall process. Aim the blunt nose towards the bridge after Abbey and keep the pedal squashed. The dark cockpit and total lack of vision alongside or over the shoulder blots out your peripheral vision. The road seems to be rushing towards you like some advanced multi screen cinema experience. The car jiggles, the downforce fighting the springs as the tiniest of ridges in the road alter the air gap beneath tunnel and road. It makes the car suddenly light but alive, as if it were bobbing on a cushion of turbulent air. The shimmying combines with the sideways forces tugging at the helmet to rattle your eyeballs. The steering fidgets in your grip. Downforce is addictive. It’s a drug.

With the exhilaration of Abbey and Bridge behind, the twiddly second gear complex is an anti-climax. The 600bhp has heated the rears more than the fronts and the car won’t tuck its nose into the turn. More power simply pushes it wider, and the steering, which two corners ago was tugging and fidgeting, has lapsed into old-Buick mode again.

Session over and reflecting in a cosy warm cockpit, there is, of course, no magic ingredient. There never is. Instead, there is a complex package which needs to be operating in total harmony, and TWR simply had theirs in better tune than the opposition’s on the day. But those main ingredients fall into two main categories. The tyres need to be in good health and fully up to temperature without these four vital footprints, the car cannot even begin to impart confidence to the driver. That initial assurance then allows him to carry the speed smoothly into the faster corners so that the second part, the aerodynamics, can do their best work. For the driver, this second part is the hardest to do, because although the XJR-6 is friendly enough once warm, it doesn’t give you any reassuring messages via wheel or seat, when the limit approaches. Instead, rather like entry into some invisible envelope, there’s a barrier which you must pass to unlock the car’s ultimate capability. This is only possible if you dare go fast enough. Once you start thinking: “Can I do that at this speed?” you will want to brake and shift down dip the nose, disturb the airflow under the car. But when you think: “It can do that at this speed,” you find you do, because it can.

“WINSTON, YOU’RE NOT DRIVING THIS CAR…YOU’RE FLYING IT!”

Some of the biggest names in motor sport during the mid’80s drove the XJR series of of racing Jaguars. But only one man — Win Percy — can truly have been said to make them fly. Ten years on, he can still remember every vivid detail of his monumental crash on the Mulsanne Straight in an XJR-6 during the 1987 Le Mans 24-hour race.

“It was around 2am, and I was in the first lap of my shift. There had been an accident at Indianapolis on the other side of the circuit and I must have picked up some of the debris in my tyres, though I thought I had missed it. Later, some of the marshalls told me that they had noticed sparks coming from the rear of the car as I entered the Mulsanne Straight, a sign that one of the tyres was deflating.

“Well, about 300 yards from the Mulsanne kink, the tyre exploded taking half the rear bodywork with it. The car just took off and bounced off the Armco barriers like a piece of confetti. At one stage I could see the tops of the trees lining the straight practically at eye level and I had time to say myself: ‘Winston, you’re not driving this car… You’re flying it!’ Eventually, it stopped barrel-rolling at 220mph and screamed down the track on its side, with my helmet being rubbed down by the road surface. I remember lifting my head out of the way as the car slowed down. The accident didn’t finish until another 300 yards the other side of the kink, but once the car had stopped rolling I was becoming convinced I would step out alive.”

In fact, Percy’s most serious injury from this 240mph crash was a small bruise on his right knee. Not a bad testament to the strength of the TWR Jaguar XJR-6.