E30 BMW M3: The Purpose-Built Group A Racer That Conquered The World
“The trophy cases at BMW are filled with the momentos of over 600 world and national championships, but nothing in motorsport history can compare with what one BMW model achieved in the space of one short year,” boasted a BMW Australia advertisement published in late 1987.
‘The BMW M3 has recently won the Australian, European, German, French, Finnish and Dutch Touring Car Championships. The same model was also victorious in the AMSCAR series as well as clinching the Tour de Corse Rally in Corsica. Then a BMW M3’s driver won the 1987 World Touring Car Championship. And, not least of all, the M3 has achieved the ultimate victory in the ultimate endurance race. First, second and third in the 24 Hour Endurance Race at Spa, Belgium.”
Those staggering achievements still pack a punch decades’ on. BMW was the first manufacturer to produce a car specifically for Group A touring car racing. The original M3 was a brilliant design that combined critical performance factors like engine capacity, minimum weight, tyre width, weight distribution and suspension design in one cohesive package that exploited the complex Group A rules to maximum effect.
On paper the M3 had all the ingredients required to be a dominant class competitor. However, prior to the start of that historic 1987 season, BMW Motorsport Director Peter Flohr gave a hint of the company’s higher expectations when he said “our car will only be able to take class titles although it is quite conceivable it will be a winner on some tracks.”
Yeah, right. Perhaps such palpable understatement was designed to lull opponents into a false sense of security, namely Ford with its equally new 2.0 litre turbocharged Sierra Cosworth RS with which it hoped to win the inaugural World Touring Car Championship.
Even so, it didn’t take long for the new M3s to expose their race-winning potential. At the opening round of the WTCC at Monza in Italy, Andy Rouse's new Sierra was trounced by a swarm of factory-supported BMWs which after 87 laps and more than 500km of racing claimed the first six places!
Although the works M3s were famously excluded after the race for running some lightweight carbon fibre panels without factory part numbers, the Bavarian barnstormers regrouped and won the next three WTCC rounds in Spain, France and Germany before scoring a resounding 1-2-3 at the Spa 24 Hour classic in Belgium.
It was only from round six that Ford started to turn the tables on the M3s with an upgrade of the Sierra Cosworth called the RS500, which had the extra power and durability required to quickly reduce the M3’s role to that of a class competitor. The Sierras beat the M3s in all but one WTCC round from then on, even though the cheeky BMWs still usually finished on the lead lap.
The exclusion on technical grounds of the two factory-backed Eggenberger Sierras that finished 1-2 at Bathurst and the dogged consistency of the M3s resulted in works driver Roberto Ravaglia winning the WTCC driver’s title by a single point.
Before the WTCC circus had arrived in Australia in October for two races at Bathurst and Calder, the Australian Touring Car Championship had been run and won by Jim Richards in a factory-backed M3 prepared with the immeasurable knowledge and experience of Frank Gardner behind it.
It could be argued that Richards’ ATCC victory was the M3’s toughest national championship win in 1987. The fleet of European works cars in the WTCC only had to contend with the factory Sierras for outright wins, but in Australia the M3s faced not only the new turbo Fords but also, uniquely, V8 Holden Commodores and turbocharged Nissan Skylines. And mostly on shorter and bumpier tracks than the European circuits it was tailor-made for.
In Australia the Cosworth-powered Sierras proved just as fragile as their European counterparts before the tougher and faster RS500 version came on stream and the Group A Commodores never won a round. The 1987 ATCC came down to an enthralling two-car fight between Richards’ M3 and young gun Glenn Seton in his works Skyline, which wasn’t decided in the Kiwi’s favour until their nail-biting final clash at Oran Park.
E30 BMW M3: The Nuts and Bolts
BMW was heavily committed to Group A racing from its inception in Europe in 1982. The company started out with six cylinder 528i sedans before progressing to 635 CSi coupes, with both models enjoying considerable success.
However, those cars were effectively road cars adapted for racing purposes with all the compromises that came with them, particularly their long inline six cylinder engines which placed a considerable amount of unwanted weight ahead of the front axle line.
By the time BMW came to developing its purpose-built Group A contender, it had developed an intimate knowledge of the rules. In simple terms, a manufacturer had to build a minimum of 5000 units of a mass-produced road-going model from which it could then build another 500 ‘sporting evolutions’ for racing purposes which still had to be legal for road use.
This was where rule expertise was essential, as Group A consisted of numerous sub-classes based primarily on engine capacities. In reviewing the M3’s dazzling debut season, Mike Jacobson provided a succinct explanation of these rule complexities in Chevron’s Australian Motor Racing Yearbook:
“Engine capacity is the fulcrum on which several major elements are balanced: minimum vehicle weight, maximum tyre width and fuel tank capacity. Generally speaking, the bigger the engine the higher the weight limit, the wider the tyres and the larger the fuel tank.
“But somehow the figures don’t add up. By fiddling the figures even within those broad parameters, certain classes have a clear advantage. Most critical is the tyre width limit, because the amount of weight carried by each inch of rubber determines a car’s ultimate performance. The higher this ‘weight-to-rubber’ ratio, the harder the compound is needed to last over a race distance (or till the next pit stop). And the harder the compound, the less grip.
“While the general public, and a surprisingly large number of movers and shakers within the sport, labour under the misapprehension that a good big car should beat a good little one, that simply isn’t the case. Under the present rules, a big capacity car (ie anything over 4.0 litres) is at a disadvantage to the ones in the smaller capacity.”
On that basis, having weighed up a multitude of permutations, BMW equipped its compact 3 Series two-door sedan with a multi-piece body kit to serve as the basis of a purpose-built Group A car tailor-made for the 2500cc class. This allowed the same 10-inch wide tyre as the 3000cc division but with a critical 75kg weight reduction (or minimum weight of only 960kg).
Keep in mind, when BMW would have been doing these sums, turbocharged engines in Group A were still in their relative infancy and yet to reach the staggering power outputs they would later achieve under the FIA’s outdated turbo equivalency factor of 1.4 when determining engine capacities (cubic centimetres x 1.4 = total displacement in cc).
One tantalising option for the M3 could well have been a turbocharged engine of just under 1800cc, which with the factor of 1.4 applied would nominally have just snuck in under the 2500cc limit. Given BMW’s peerless expertise in turbocharging small engines, as proven by its 1983 F1 championship win with Brabham, the temptation must have been strong.
However, an F1 car only had to cover a race distance of around 300km in a Grand Prix, whereas most rounds of the WTCC would be at least 500km plus 1000km at Bathurst and more than 3000km at the Spa 24 Hour.
Therefore durability over long distances was crucial. Given the notorious heat-related issues with turbocharged engines, particularly the potentially damaging effects of under-bonnet ‘heat soak’ when they have to be switched off for refuelling during pit stops, meant a naturally aspirated engine was the only way to go.
But which engine? As previously mentioned, BMW’s Group A experience with inline six cylinder models had resulted in too much weight being carried by the front wheels to achieve optimum chassis balance. And the longer a crankshaft, the more vulnerable it is to torsional vibrations at high rpm.
A four cylinder was the best option so a re-engineered derivative of the 2002’s trusty M10 unit was developed called the S14, featuring a new big breathing 16-valve DOHC cylinder head and the latest Bosch Motronic fuel injection. Its 94mm bore and 84mm stroke at 12:1 compression was as far as BMW wanted to go in maintaining good durability margins in race trim, even if its 2.3 litre cubic capacity fell a bit short of the 2.5 litre class limit.
Such an oversquare bore-to-stroke ratio thrived at high revs, producing its peak 300bhp at a spine-tingling 8000rpm. By comparison, maximum torque was only 200 ft/lbs at 7000rpm. That was not an issue on long, fast European circuits like Monza, Spa and Silverstone but not ideal on Australia’s generally shorter and tighter tracks favouring good punch out of slow corners.
Getrag designed a close-ratio five-speed gearbox specifically for the M3 which fed power to the rear wheels through a ZF differential, homologated with a choice of seven final-drive ratios to cover all circuit requirements on the WTCC tour.
And the little M3 was blessed with phenomenal braking, which often appeared to defy the laws of physics. A quartet of huge disc brakes (332mm front, 280mm rear) clamped by powerful four-spot calipers - combined with the small and lightweight M3’s agility - made life hell for rivals at the end of any straight.
“The suspension came first and the body was designed to fit around it,” wrote Jacobson about the final magic ingredient in the E30 M3’s winning recipe. “Read any road test of the car and you won’t find many compliments about the rear seat room. Now you know why.
“If there’s one thing that Group A really sorts out, it’s which cars give their tyres a hard time. The width limits are fairly narrow considering the amount of weight they have to carry over fairly long distances.
“What this adds up to is the importance of keeping the rubber as flat on the road as much as possible. Take into account the tendency of the latest radial racing tyres to slip sideways as their sidewalls flex under cornering loads and you’ve got to be able to set a fair amount of negative camber into the geometry.
“Once again the limitations of production cars become apparent. They aren’t designed with such radical modifications in mind. Front ends usually don’t pose any problems; it’s the rear where manufacturers leave race engineers no room to manoeuvre.
“Even cars with independent rear suspensions rarely allow full-width racing tyres enough lateral and vertical movement. And as for dinosaurs like Holden’s Commodore, they’ve got trouble with a capital T.
“For (Frank) Gardner, who cut his teeth in racing and sports cars, it was a major improvement over earlier BMWs: ‘You take the temperatures across the tyres and if they’re reading 120, 120, 120 (Centigrade) then you’ve got the optimum camber and toe-in. With the 635 we couldn’t get the tyres absolutely right.’”
The Aussie works M3s
The combination of Frank Gardner, Jim Richards and the JPS BMW team had already proved its effectiveness when their factory-backed BMW 635 CSi dominated both the 1985 Australian Touring Car Championship and Australian Endurance Championship in the first year of local Group A racing.
So in 1987 the winning formula didn’t need to change. Like the 635s, the new M3s for Richards and team-mate Tony Longhurst were built from scratch at the team’s Terry Hills workshop in Sydney’s north. And Gardner continued to do the bulk of the test and development driving himself at Sydney tracks, where his vast experience played a key role in ongoing refinements.
Rather than import factory-built ‘turn-key’ race cars from Germany, Gardner insisted on building his own cars tailored to suit Australia’s rougher circuits. The roll cages were fabricated from military-grade low-carbon steel tube rather than the usual chrome moly to provide greater chassis rigidity than the European cars. He also worked closely with Italian tyre supplier Pirelli to develop a unique compound tailor-made for Australia’s warmer track temperatures.
The Aussie BMW squad was the first to blood the M3 when it made its world debut at the opening round of the 1987 ATCC at Melbourne’s Calder Park on March 1, having only received its FIA homologation approval the same weekend.
It didn’t take long for the new Bimmers to reveal their formidable potential, with Richards scoring his first outright win in round three at Queensland’s Lakeside Raceway. His finely-tuned race package continued to get stronger as the season progressed, never finishing lower than fifth in all but one of the nine rounds. He scored four outright wins to arch rival Seton’s three, which included his decisive victory in the final round at Oran Park in July.
The Kiwi was a most deserving champion and it was the highpoint for the original E30 BMW M3. Although it continued to compete in Aussie Group A racing through to the category’s demise in 1992, the M3 never reached the same championship-winning heights as it did in 1987.
Not only in Australia, but around the world. BMW’s bold claim in that glossy print ad that “nothing in motorsport history can compare with what one BMW model achieved in the space of one short year” is a claim not without foundation. On reflection, the original E30 M3 is arguably the world’s greatest touring car.