There were also naturally aspirated or turbocharged 2-litre diesels. Both normally aspirated and turbocharged engines are permitted. This was powered by the 13B rotary engine, offered in naturally aspirated or turbocharged forms. Both versions were available in either naturally aspirated and turbocharged form. Wankel engines can also be classified based on whether they are naturally aspirated or turbocharged. It has been produced in both naturally aspirated and supercharged configurations. The Series 1 was produced in both supercharged and normally aspirated versions. Both used the 2.5-litre naturally aspirated diesel engine. The regulation expected to bring a new balance between supercharged and normally aspirated cars. Both cars were to be powered by naturally aspirated V8 engines. An automatic transmission was optional with the naturally aspirated engine. L naturally aspirated engine from 1991 on. Awarded to constructors of cars equipped with naturally aspirated engines. Awarded to drivers of cars equipped with naturally aspirated engines. Voiceless stops are only lightly aspirated and voiced stops are fully voiced.