Trojan Horse - 1986 Opel Kadett GSi Rallye 4x4 Group B Prototype

German people’s car manufacturer Opel had been an avid competitor in the world of international rallying since the late 1960’s. Like their road cars, the rally versions were always built on traditional proven principles. The approach proved successful, as Opel’s cars were always highly competitive. Sturdy, bulletproof engineering, fuel injected engines and light responsive chassis made sure Opel were a force to be reckoned with.

With star driver Walter Röhrl, Opel scored their first major international success by winning the Driver’s Title in the 1974 European Rally Championship. The surprise success saw Opel move up a notch to try their luck at the world stage. Surprisingly, reliability problems with the new Kadett C Coupe put a stop to Opel’s charge through the ranks, and made them lose Rörhl to bitter rival Fiat.

The slump in the company’s progress was caused by the fact that Opel itself did not have a dedicated motorsport department. Instead they relied on work from various independent tuners like Irmscher to design and run the rally cars. The tuners and teams received little in the way of financial support, but were still running the yellow and black factory colors.

Walter Röhrl and Jochen Bergen on their way to the 1974 ERC title.

For the 1980's this plan would have to be changed. Now with a more serious attitude towards competing, Opel instigated the design of two cars meant to conquer the global rally stage. The Manta B 400 and Ascona B 400. The cars were wheeled out in 1980, and competed in select events on the WRC calendar.

But with the arrival of the manic turbocharged four wheel drive Audi quattro, it seemed like the cars were outdated from the start. The naturally aspirated 270 horsepower cars appeared powerless against the 350 horsepower turbo Audi. And yet, in its first full season of competition, the Ascona 400 performed the impossible.

Guided by the returned Walter Röhrl, it took the 1982 driver's title from under the nose of Audi's Michele Mouton. The victory was to be the last WRC drivers title won by a naturally aspirated car, the last to be won by a carbureted car ánd the last to be won by a rear wheel drive car.

The Opel Ascona B 400 became an eternal legend in the WRC's history books.

The Ascona 400's amazing success had Opel over the moon, but it was clear that rear wheel drive and natural aspiration were yesterday's news. Something had to be done to keep up with the four wheel drive turbo revolution. To this end Opel looked closely to rivals Audi, who were actually using a comparatively big, clumsy mess of a car with terrible weight distribution.

The only reason the quattro got ahead was because of its superior traction and its greater power. Lighter, more nimble cars like the Ascona and Lancia's sportscar-like 037 were able to beat it on tight tarmac stages. The advantage gained by the Opel totally disappeared on looses surfaces however, as the car was still based on design principles from the 1970's.

The original quattro was actually a rather large and cumbersome beast

With this in mind Opel sought to combine all the advantages of Audi's technological wizardry, and combine them with good old-fashioned lightweight nimbleness. The change to the vastly more liberal Group B rules in 1982 made this a viable proposition. Opel could now base their car on anything they liked, and incorporate whatever technology they liked.

As long as they built 200 road going homologation versions of it, everything would remain hunky dory. The search for the smallest possible vehicle ended late in 1984 with the brand new Kadett E, Opel's answer to the Volkswagen Golf. Coincidentally the Kadett was to be the company's top seller, which provided a handy marketing opportunity.

The humble family hatchback was to become Opel's new rally monster.

A front wheel drive, transverse engine hatchback was nowhere near what Opel wanted, so it was simply cut into three pieces. Only the middle section of the monocoque survived, with the front and rear replaced by steel spaceframes. With exception of the steel roof, all body panels were constructed out of a kevlar-based composite to keep the weight down.

Along with uprated suspension components, the new spaceframe still carried the Cosworth-engineered 2.4L carbureted straight 4 engine from the Manta and Ascona. The engine was mounted longitudinally in the front to make room for the specially developed X-Trac 6-speed manual transmission and four wheel drive system.

The engine layout bore no resemblance to the economy car it had been based on.

Using the Manta engine provided a bit of problem. In the intervening years Group B's front runners had breached the 400 horsepower mark, and showed no sign of stopping. The 2.4's meager 270 horsepower paled in comparison. Rather than jump to turbocharging immediately, Opel inexplicably tried supercharging first.

The Sprintex supercharger did not have the desired effect however, improving performance to just 340 horsepower. Realizing their mistake, the supercharger was ditched and a turbo was quickly slapped onto the lackluster engine. The result was a reasonably competitive 400 horsepower, but now the engine refused to stop breaking down.

The lack of reliability and competitiveness sent Opel into a bit of a panic. Knowing they were fully out of options, they turned to a familiar method: trying to get others to do it for them. To this end they contacted famous German tuners Zakspeed. Over the years Zakspeed had seen numerous successes in touring car racing with Ford and Mercedes, and were now ready to take on Formula One.

Opel saw in Zakspeed the ideal partner, and commissioned them to build an engine for the ailing rally project. Zakspeed enthusiastically agreed, and had an engine ready in record time. The unit was a 1.9L turbocharged straight 4, which could reliably produce 500 horsepower. This was exactly the figure Opel had been looking for. At a press conference, the company proudly announced the acquisition of their new powerhouse.

The remarkably positive presentation raised quite a few eyebrows with the automotive press. After a little digging it was quickly discovered the engine was a horribly massive public relations disaster. It was for all intents and purposes....a Ford. Somehow, Opel had failed to realize the tight bond between Zakspeed and their arch nemesis.

As a result they had been eagerly bragging about a vastly superior and more powerful engine, which had been made by a direct competitor. Zakspeed had simply given them the engine from one of their old Ford Capri Group 5 racers. Unsurprisingly, the fallout from the incredibly idiotic incident was immense.

The blunder was overshadowed by several tragic accidents during the 1986 season, which saw Group B rallying banned indefinitely. Opel's red-faced management was now free to quietly toss the Ford engined car aside.

The focus shifted to preparing the Kadett for Group S, the category meant to replace Group B's unrestricted madness. For Group S engine power would be limited to 300 horsepower. This meant Opel could use the 2.4L Cosworth engine competitively again, allowing them to somewhat restore their shattered reputation.

The supercharged prototype, Vauxhall Astra 4S.

Opel had built a chassis to test each version of the engine: the naturally aspirated 2.4, supercharged 2.4, 2.4 turbo and Zakspeed Ford turbo. Three of the cars had been branded as Opels. Meanwhile, the supercharged car was marketed as a Vauxhall Astra to appeal to the British market. With the understanding that the 1988 Championship would be contested under Group S regulations, the Vauxhall was entered into the 1986 British Rally Championship under Prototype rules, driven by Andrew Wood (GB).

Weighing in at a relatively heavy 960 kg (2116 lbs) and still producing just 340 horsepower the car was ill-equipped to fight exiled kings like the Ford RS200 and MG Metro 6R4. Nevertheless it finished a fine 4th, giving parent company General Motors hope for the future. In preparation for the arrival of Group S, the engineers were already working on bringing the car's weight down to a sprightly 850 kg (1873 lbs).

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In a side project, Opel had adapted two of the 4x4 chassis to compete in the famous Paris Dakar Rally. The cars sported the more reliable naturally aspirated 2.4L engines and uprated suspension. In addition their chassis had been strengthened in key points, and 300L fuel tanks were fitted.

The measures helped the Opels withstand the rigors of the desert, but also made them considerably heavier than the Group S Vauxhall. In addition the engines had been downtuned to 250 horsepower, to make them able to stomach the appalling quality of Africa's gasoline.

Dressed in the evocative Bastos livery, the cars were given to Belgian regulars Guy Culsoul / Alain Lopes and the German team of Erwin Weber/ Günther Wanger. Colsoul and Lopes had already tested with the Group S version of the car, and had been thoroughly impressed by its performance.

"It was unbelievable. At first I couldn't even take my hand off the wheel to shift. That's how hard the car pulled at my wrists. Alain Lopes usually sat beside me, and at times he seemed to turn grey. That's how fast that thing is."

Guy Colsoul

The lighter and more powerful Group S car had given the Dakar competitors all the wrong ideas, as the Dakar version was a completely different animal. Persistent problems with the altered suspension and engine issues immediately plagued the unique machines. As a result Weber / Wanger were helpless during the rally. Colsoul / Lopes managed to bring the car home in 40th place, bitterly disappointed.

The Kadett's African adventure proved to be another deception.

The end of the 1986 season brought another surprise for Opel, as the FIA announced the cancellation of Group S. Group B's extreme danger had brought down the lesser alternative with it. Starting in 1987, Group A would become the WRC's top category.

With Group S stillborn, Opel's chaotic rally project was finally at an end. To make ends meet one of the Dakar cars was sold off to two time British Rallycross Champion John Welch. The car was lowered again from its cross country setup, and modified to fit tight twisty circuits. Welch kept the 2.4L engine, but mated it to the satanical turbocharger from BMW's M12/13 Formula One engine. The result was a savage 650 horsepower.

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Like all Group B rally cars after 1986, the Kadett/Astra was driven into the brutal arena of rallycross. There it faced the very cars it was constructed to beat. The Group B ban had forced the mighty Peugeot, Audi, Ford, MG and Lancia into exile. Now they where beating each other senseless like gladiators.

Among this collection of titans the steriod-infused Vauxhall managed to hold its own. John Welch would continue to run the car through to 1992. Sadly the car would fail to give him another title.

John Welch's interpretation of the car was the best yet.

The Opel Kadett GSi Rallye 4x4 / Vauxhall Astra 4S was a real mess of a project. Confusion and mismanagement saw the car sport four wildly different engine variations, of which just one actually worked at an acceptable level. Sadly this engine turned out to be made by the enemy, making the car a veritable Trojan Horse for rival Ford. The monumental cock-up damaged GM Opel's reputation massively, and put further strain on the project.

The turbulent times during which the car was developed also took their toll. The cancellation of Group B forced the engineers to make a drastic turn in yet another direction. Undoubtedly under enormous stress because of continuous uncertainty, one can imagine a sigh of relief from the engineers when Group S failed to materialize. Their frantic work was finally over. The failed project was then deported to Great Britain, where it and its Group B siblings would entertain TV-audiences for many years to come.