40 Years of Opel Manta B 400
At the 1981 Geneva Motor Show, a car debuted that would probably no longer be possible in this form today. A German subsidiary of a major American corporation collaborated with an independent tuning company to create a homologation vehicle for rallying. Nowadays, this chain of words alone rings all the alarm bells among the tie-wearing business economists who now sit in decision-making positions at most car manufacturers. At the end of the 1970s and the beginning of the 1980s, Irmscher had already proven several times that tuning should not necessarily be equated with tinkering. This led to the fact that their products were officially available through the Opel dealer network and special edition models were developed together. On of these was the Manta B i2800.
Engine with Cosworth cylinder head
When the regulations for Group B in the World Rally Championship became known, Opel decided to develop a corresponding car based on the Manta B. This was to succeed the Ascona B 400, which was built according to Group 4 regulations. The greatest success of the Ascona B 400 came just after the presentation of the successor, when Walter Röhrl and Christian Geistdörfer won the world championship title in 1982. Opel originally wanted to use a two-liter four-cylinder engine for the new car. For this purpose, Cosworth developed new 16-valve cross-flow cylinder heads. However, these engines didn’t achieve the desired performance. Since the cylinder heads had already been produced, a new forged crankshaft was designed for the engine block, increasing the displacement to 2.4 liters. This resulted in 106 kW/144 hp in the road version and more than 184 kW/250 hp in the competition car. A turbocharger was considered unnecessary.
Wide-body package only at extra cost
From the outside, the basic version of the Manta B 400 stood hardly changed on its 15-inch alloy wheels. However, Irmscher offered the widebody, spoiler lips and wider rims used for rallying as an optional package. For 9,410 DM, the car then looked almost as wild as its rally siblings. There was also the option to boost the engine to 250 hp with a tuning kit. Later, there were Phase II and Phase III packages for up to 280 hp. This reduced the acceleration time to 62 mph from 7.5 to 5.5 seconds. The first 23 road cars of 1981 are recognizable by a radiator grille with only two slots. From the beginning of 1982, four slots can be found here. On the rally cars, a lamp tree with four auxiliary headlights often sat in the same place. Originally, only the color “Arctic White” was to be available, but cars in black and silver are also known.
Delayed homologation
The model name Manta B 400 refers to the former Group 4 of FISA, for which 400 cars had to be built. To participate in Group B, Opel had to prove production of 200 units of the new car. Homologation for the World Rally Championship proved difficult. The acceptance had already been registered with FISA in the fall of 1981. However, important components were initially missing on the Antwerp assembly line, which meant that only 23 cars were ready by the end of the year. Not enough for homologation. In the end, this didn’t take place until September 1982. As a result, the first rally cars didn’t compete until 1983, when it was already clear that the Audi quattro’s all-wheel drive system couldn’t be matched by the Opel. In 1982, Opel had built an AWD Manta prototype together with Ferguson in Coventry. However, this failed due to poor handling and the cost of a further homologation series.
Successes in motorsport
A total of 245 units rolled off the production line until 1984. Around 25 of these were entered in various rally championships and on circuits by the factory team (1983 only) and many private drivers. Other vehicles were used up in rallycross events. The Manta B 400’s greatest success was winning the rear-wheel-drive class in the 1984 Paris-Dakar Rally along with fourth place overall. Erwin Weber and Gunther Wanger also won the German Rally Championship in 1983. At the NLS (formerly VLN) on the Nürburgring Nordschleife, an Opel Manta B 400 still competes today and enjoys a large fan base. Well-preserved examples of this last Opel factory rally car with rear-wheel drive are now rare and cost a tidy sum. Compared to other homologation cars like the Lancia 037, however, they are almost still cheap.
Images: Opel
