Other special jobs were undertaken at the Rüsselsheim factory. One that was too exotic to be typical was the construction of an intercooler for the supercharger of the famous Junkers Jumo aircraft engine. Special methods had to be developed to fabricate this vital assembly from very thin sheets of aluminium. With work like this going on, Germany's enemies naturally took note of the various Opel plants, and starting in August 1944, began attacking them by air. Destruction was heavy at both Rüsselsheim and Brandenburg from the attacks by Allied bombers. Never was the outlook bleaker at Adam Opel AG than in the first months of 1945.
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).