As it turned out, the Opels were still lacking in this department. Manuel Reuter was fastest of the two with 5th on the grid, while Keke Rosberg clocked a disappointing 9th time. Both managed to be slower than several of the lesser Mercedes. Both races left much to be desired as well, with Rosberg finishing 7th in Race 1. Reuter retired with electronic gremlins after just 6 laps, and was forced to miss Race 2. Rosberg was felled by similar issues in Race 2, and slowed after 10 laps.
The new four-cylinder, oversquare one-litre water-cooled Opel OHV engine weighed only 96 kg and was the first all-new engine developed by Opel since before the war. The side-mounted camshaft was driven not through gear-cogs but using a single chain with a hydraulic tensioner, the valve train employing rocker-arms and light-weight hollow rods. The arrangement was low on weight and on friction, permitting engine speeds above 6,000 rpm. The pistons were formed from an aluminium-alloy and incorporated a bimetal expansion strip to ensure uniform thermal expansion. The three-bearing forged crankshaft was of more traditional construction. The carefully designed aluminium inlet manifold provided for efficient feed of the fuel-mixture to the cylinders and helped provide the engine with good fuel economy characteristics.
The GSi's engine mapping had been carried out by Opel tuning specialists Irmscher. A model with the 82 PS (60 kW) 1.4 L multi point fuel injected engine, which was otherwise mechanically identical to the GSi, also became available as the Nova SRi in the United Kingdom. In January 1988, a turbocharged version of the Isuzu diesel engine was introduced, with power increased to 67 PS (49 kW).[8]