ROCKET SCIENCE

BUILT IN THE TWILIGHT OF THE INFAMOUS GROUP B ERA, THE UNIQUE, NATURALLY ASPIRATED METRO 6R4 WAS A UNICORN OF THE GENRE. WE DRIVE IT

BY JOHN - JOE VOLLANS + PICS CHIPPY WOOD

NEW MOTORSPORT regulations are rarely cause to get excited. They’re mostly about tedious attention to detail such as wing and tyre widths. Group B, however, was very different.

It fired the collective imaginations of a generation of engineers and resulted in some of the most fearsome fourwheeled machines ever to see competition. They were loud, visually wild and ferociously fast.

Making a 300kW-plus MG Metro that could accelerate standstill to 100km/h in 3.2 seconds, regardless of the was far from straightforward. It would involve an number of people from the UK’s car-making and industries coming together and finding innovative problems that most hadn’t even conceived a few months before.

Like Aussies, the Brits love underdog stories. I think it’s our cultural DNA. Both countries seem to gravitate plucky few who go against the grain. So it was no when Austin Rover chose the little Metro to join the ranks. We know you’re all familiar with Group B and significant position in the pantheon of stage rallying. For who’ve lost their memories, or who know nothing consider this the very briefest of (re-)introductions.

GROUP B WASN’T LONG FOR THE WORLD, BUT CUTTING IT OFF IN ITS PRIME TURNED THE 6R4 INTO A TRUE LEGEND

By the end of the 1970s rallying was not only a hugely popular sport, it was translating into sales for manufacturers. limitations in the rules meant that development was makers such as Lancia and Renault were frustrated limitations placed upon them when designing gravel vehicles. There was a desire to reduce and simplify the allow for faster, less restricted and more focused rally be created, without the need to manufacture so cars for homologation (200, down from 400).

January 1, 1982, four new competition ‘groups’ of rules created, Groups A-C and an additional category of Group N for standard production cars. This opened the floodgates for manufacturers to commit to rally programs at all levels. Group B had the potential to be the most exciting. It did away with much of the red tape and restrictions from the old Group 4 and 5 international regulations.

Forced induction, four-wheel drive, mid-engine layouts and the use of composite materials soon became obligatory to remain competitive. Furthermore, the body structure of the cars and their aerodynamics no longer had to resemble any production models. This allowed for full rally prototype machines to emerge with spaceframe construction, unlimited engine performance and only the tyre width and safety equipment strictly controlled.

ONE The 6R4 used permanent all-wheel drive, running a 35:65 torque split via a Ferguson centre diff

TWO Longitudinal, drysumped 3.0-litre V6 was unique. A twinturbo 2.3-litre version was used in rallycross

THREE Half a tank is used every 15 minutes when searching for the MG Metro 6R4’s glorious 10,000rpm cutout

To that point, Austin Rover had been unsuccessfully fielding the TR7. When it gained the Rover V8 engine though, it proved to be a serious tarmac contender. However, it lacked the suspension travel and drive sophistication to cut it on the slippery gravel and snow stages. Getting wind of the upcoming regulation change, Austin Rover took the opportunity to replace the TR7 with a custom-built rally car, but realised there was a gap in its expertise.

Fortuitously for Austin Rover’s competition department and its director John Davenport, British Leyland had been sponsoring Frank Williams’ F1 cars that year. A deal was done and Williams set to work creating a new prototype sharing the MG Metro’s wheelbase (but little else).

By early 1983 a single prototype, powered by a cut-down version of the Rover V8 (called the V62V) was delivered by Williams. An entirely new V6 engine (still thought to be the only engine ever made specifically for a rally car) was under development (the V64V), but to speed up the process for the chassis development team, the V62V was used until its bigger brother, developed at Austin Rover by former Cosworth engineer David Wood, was ready. Running V62V-powered cars were handed back to Austin Rover at the start of 1983, and it was quickly discovered that there’s a big difference between making Formula One cars and rally cars, as the lightweight components used to great effect in F1 wouldn’t stand up to the rigours of professional rallying.

TAKING THE ATMO ROUTE GAVE THE 6R4 ACCESSIBLE

THE ENGINEER: ‘IT HAD A LOT OF UNREALISED POTENTIAL’

AUSTIN ROVER Motorsport senior engineer Wynne Mitchell headed the team that developed the 6R4 from a F1-inspired prototype from Williams into a machine capable of taking rally wins. “There were two senior engineers on the 6R4 project, me and David Wood,” he says. ‘David looked after the engine, while I, Richard Herdwell and Bernie Marcus did the rest.” “I joined during preliminary testing of the Williams prototypes. “I went out on those fi rst exploratory laps with Tony Pond in Spain and he kept spinning. I thought, what the hell have I let myself in for? We cured the handling problems, but even by the end of Group B, we were still ironing out glitches and in no way developed the 6R4 as far as it could go. However, there wasn’t the funding or time left to complete the car, which I always felt was a missed opportunity.”

The wheelbase of the Metro was found to be too short and Williams had widened the rear track without matching the front. Together this meant that the early cars were notoriously twitchy. The solution was to increase the wheelbase by three and three-quarter inches, widen the track by another three inches and do the same to the front. Turretting the front and rear suspension allowed for the specified 10 inches of suspension travel. Then Michelin dictated a change of wheel size from 13-inch to 15-inch to accommodate its new 390mm tyres. This meant power steering was necessary, giving the 6R4 more front castor and further directional stability.

Chassis sorted and ready to compete, the Ferguson Formula, four-wheel drive set-up was mated to a bespoke Austin Rover motorsport five-speed dogleg transmission and the now finished 3.0-litre 64-valve (V64V) quad-cam V6 engine was mounted behind the driver. This came in two states of tune - a 186kW Clubman version and the full fat 306kW Works spec. Only the steel A- and B-pillars and both sides of the bodies were shared with roadgoing Metros. Everything else was bespoke.

GRUNT, BUT IT ALSO SIGNED ITS OWN DEATH WARRANT

ONE The MG Metro 6R4 gained a significant brake upgrade, with 305mm ventilated discs and four-piston calipers front to back

TWO Heavily turbocharged, small-capacity engines and tricky computer-based technology is a hallmark of Group B

THREE Rally legend Walter Rohl once said of the British rally ace; “I’d rather have Tony Pond in my team than driving against me”

FOUR Pedals are ideally placed for heel-andtoe fun with the fivespeed manual gearbox - no sequential unit like modern WRC

The car pictured, the one we got to put through its paces, is one of the first 200 early-production homologated cars. It played a further role, as a press demonstrator. In the hands of Austin Rover motorsport drivers Tony Pond and Marc Duez, it was used to take assorted motorsport press out for high-speed demonstration laps around a mock rally stage in May 1985. This was the official launch of the firm’s Group B international rally campaign. The day after, the car competed in the Autofit Argyll Stages Rally where, with Pond at the wheel, it won all nine special stages and finished first by over three minutes.

This car was then taken out of competition, only appearing publically once more at the 1988 Birmingham Super Prix in a 6R4 support race. After that it dropped off the radar. That was until its current owner, James Leask, saw a classified ad in the early 1990s. He bought the car and slowly returned it to its original full Works specification.

That brings us right up to the present day where we come face-to-face with B197 XUD at Curborough Sprint Course in Staffordshire, UK. Fans of the 6R4 are passionate. These guys live and breathe Metro 6R4s and today there’s more than 20 of these rare rally weapons gathered for a far from average track day. As we make our introductions and chat, we can’t help shifting our gaze over Nicky and Jim’s shoulders to the car. History seems to emit from every flared arch and safetywire secured bolt on this special machine. It’s period perfect because it’s hardly changed since 1985. And the last time this 6R4 turned a wheel in anger it was driven by Tony Pond... so no pressure, then!

Tension and excitement builds further as the session gets under way. We’re mere feet away from a line-up of idling 6R4s. The variety of models from Clubman and rallycross contenders, right up to rare prototypes and full works machines, is educating. We had no idea there were this many variations.

With a V6 roar, a chirrup of tormented rubber and a smell of raw fuel the first 6R4 is away. It’s enough to make the hairs on the back of your neck stand up. We line up at the back of the queue as we’re not due to go out until the lunchtime pause.

In next to no time we find there’s only a few more cars ahead of us. Then it’s here, we’re at the front of the queue, the last car out and all eyes are on us. This is getting very real indeed.

There’s a stillness of anticipation as spectator and driver hold their breath. I put the dog ’box into first with a satisfying clonk and build some revs. Then the marshal drops the flag and a burst of energy explodes from just behind my head. The V64V engine shatters the calm.

Throttle nailed and clutch released the 6R4 grips immediately and hurtles forward, causing my eyes to widen with the ferocity of the thing. The first corner of Curborough’s short circuit is immediately out of the pit exit and here we gingerly try the brakes. There’s very little response. We push a whole lot harder. Toward the bottom third of the pedal there’s a noticeable reduction in speed but it’s still alarmingly lethargic.

THE REV COUNTER GOES ALL THE WAY TO 10,000RPM

ONE Plastic air boxes and aerofoils cloak the fibreglass bodyshell featuring an aluminium roof and steel doors

TWO Alcantara-wrapped steering wheel was made easier to turn with the addition of light power assistance

THREE Halda rally computer was, for its time, bang up to date and helped the co-driver navigate

FOUR It’s hard not to smile when an atmo V6 is screaming towards its redline... right behind your eyes. Brilliant

Mustering some considerable force, and by this stage worrying about falling off the track on the first corner, we bury the middle pedal and finally find some decent stopping power. Phew! The brakes are there and they’re pretty good, but the pedal travel initially throws us off guard.

Turning in for the first corner the power-assisted steering is well weighted and allows us to turn the comically wide front tyres with ease. It’s assisted in the old-school manner, just providing enough to take the strain off the driver without killing feedback. Clipping the rumble strip on the apex our spine gets a pounding as, unsurprisingly this tarmac set-up is pretty firm. The bonus is that in spite of entering a little too quickly, due to our lack of familiarity with the brakes, things stay almost completely flat. A long left into a right allows us to feed the throttle in and change up to third. The shift is the very definition of mechanical precision.

Weight transfers through the corners with little drama and again confirms minimal roll. Our confidence is high. The 6R4 doesn’t appear to deserve its widow-making reputation.

A 90-degree right-hand bend is all that stands between us and the start/finish straight. Apexing early allows us to get the 6R4 pointing in a straight line and with the throttle slammed wide open, we get the merest glimpse of what this car must have been like to use in competition.

The 306kW fed to all four wheels by the straight-cut Austin Rover transmission allows for instant increases in speed. The upshift is so fast it feels like a sequential. The speedo might be out of sight, offset to the passenger side, but the cacophony of engine, gear and tyre noise leaves you in little doubt that you’re travelling at serious speed. The only instrument in the driver’s eye-line is a large VDO rev counter which goes all the way to 10,000rpm. Heel-and-toe blips on the downshifts make the transmission’s life easier and allows a little engine braking on the overrun, with delicious, pops and bangs.

With each subsequent lap, speed builds. The 6R4 gives you the confidence to push harder until... under braking, if you leave more than the slightest bit of lock on the wheel, the rear tries to overtake you. The worst example of this comes 15 minutes in as the engine starves of fuel going around that 90-degree bend. The sudden deceleration shoves the tail into a slide, but power comes back just in time to drive the car straight again. We return to the pits, still buzzing with adrenaline.

Being let loose in this piece of motorsport history has to rank among one the greatest driving experiences I’ve encountered. The 6R4 isn’t nearly as fearsome as its reputation suggests, but its wide track and short wheelbase does make it nervy and difficult to control under hard braking.

We’re sure that on a loose surface this characteristic is amplified even further, but this is exactly what a rally car should do. Rather than its contemporary rival, the Audi quattro, which is dogged by near endless understeer, the Metro pivots around that rear-mounted V6.

The 6R4 arrived late to the Group B party but it did so fully developed and competitive. It might have only secured a WRC podium place once, but this was more to do with its rivals upping the firepower than with any fundamental issue with the chassis. Taking the atmo route gave the 6R4 instantly accessible grunt, but it also signed its own death warrant.

Group B was all about boost and without forced induction, the 6R4’s days were numbered. By 1986 even 306kW wasn’t enough to compete with the newly introduced Peugeot 205 T16 or the Audi Sport quattro, both of which pumped out more than 450kW.

The 6R4’s engine would eventually receive a pair of turbochargers, but that was fitted to the Group C Le Mans cars - and look how well they did. It also replaced the promised V12 engine that never appeared in the XJ220. Winning Le Mans and powering the world’s fastest production car is quite the CV. What would have happened if this turbo’d engine had found its way into the 6R4?

Sadly Group B itself wasn’t long for the world, but cutting it off in its prime turned the 6R4 into an instant legend.