In 1979, Opel wanted to get into rallying again. They had attempted a rally program using the Kadett and had failed miserably, and drivers had been complaining about some of the handling characteristics of the Ascona, so to hedge their bets for success, the brand chose their sporty Manta coupe as the next rally platform, aimed for the Group B ranks and partnered up with two companies: Cosworth, the famed engine building and engineering firm, and German tuner Irmscher, who had previously worked on the Manta i2800, for bodywork and interior design.
The engine proved to be the sticking issue. Cosworth had been given the task of building a 16V four-cylinder head for the Opel family of engines. Cosworth built the heads before development of a full powertrain. Originally Cosworth tried to use the 2.0L Opel four-cylinder with a Cosworth 16V head on it, but the engine simply didn’t produce power. Since the head and engine were meant to go together, Cosworth came up with a plan to use the crankshaft from the similar 2.3 diesel four-cylinder in the block, and to bore out the cylinders, resulting in a 2.4L four cylinder that in race tune could push over 300-350hp naturally aspirated. The engine breathed using a pair of Weber carburetors mated to a 4-into-1 intake manifold. Keep in mind, these were close to factory specifications…it’s long been rumored that this hyperactive little mill could push into the 400hp territory with a little work, and with the right gearing would make it would make the Manta absolutely nasty.
Unfortunately, like most other RWD rally cars developed at this time, there was a storm coming from Germany that was about to rain on everybody’s parade: the Audi Quattro. The Quattro’s place as a rally revolutionary has been well documented, but even if the Manta and the Quattro didn’t meet, the Manta had stiff competition from the likes of Lancia’s 037 and Renault’s R5 Turbo, mid-engined race cars that had been simply homologated for street use. Even worse for Opel was the reliability issues that plagued the Manta’s early rally days, with head gaskets and axles for the independent rear end needing constant attention. The Opel’s tendency to understeer displeased Opel driver Ari Vantanen enough that he bailed the team for Peugeot in 1984.
The sad part of the Manta’s story is that had it come out two years earlier it would have been a great racer. The car was seriously fast, not just by RWD standards but period, and if Opel had managed to address all of the issues that the Ascona rally car had during the development of the Manta program the cars would have been all but untouchable until the debut of the Audi. Unfortunately for the Manta, when the competition is brutally on-point, every little flaw and fault becomes one more move to the back pages of the history book to make way for the even more violent, capable machines.
