The 315 was the base model from March 1981 to 1983 and remained on sale up into 1984 for some markets, alongside the new E30. It has a version of the 316's 1.6-litre engine, tuned for fuel economy. It accelerates to 100 km/h in 14.8 seconds and has a top speed of . In an effort to further lower the price, the 315 also had bumpers with exposed screws, a vinyl-covered parcel shelf (this was carpeted on all other E21 models), no map pockets on the doors, R2 double filament headlamps (rather than halogen units), and a single external mirror. 316 The 316 was the base model for years 1975 to 1981, fitted with a M10 engine producing . It accelerates to in 14 seconds and has a top speed of . In 1980 the engine size increased to 1.8 litres (after the 318 carburetor version was discontinued), while the model badge remained "316". Power remained but top speed increased to . 318 The 318 was a mid-range model that was powered by a carburetted four-cylinder engine, producing . It accelerates to 100 km/h in 12 seconds and has a top speed of . 318i In 1980, the carburetted 318 was dropped and replaced by the fuel injected 318i. It accelerates to 100 km/h in 11.5 seconds and has a top speed of . In Sweden, the 318i was badged 320i and had twin headlights. This was the result of the 2-liter engine not passing Sweden's particular emissions standards at the time, which also restricted the output of the engine to in Sweden as well as Switzerland. 320 The initial 320 model was powered by a four-cylinder engine using a Solex 2-barrel downdraft carburettor. It accelerates to in 11.5 seconds and has a top speed of . 320i The 320i was released in late 1975. It has a continuous port injection system (Bosch K-Jetronic) instead of a carburetor. It accelerates to in 10.5 seconds and has a top speed of . 320/6 In 1977, the 320 model switched from the BMW M10 four-cylinder engine to the BMW M20 straight-six petrol engine. Although they remained badged as "320", the six-cylinder model is often referred to as "320/6". The engine uses a Solex 4-barrel downdraft carburetor. The 320/6 accelerates to in 10.0 seconds and has a top speed of . 323i The 323i was the top E21 model following its introduction in