1977. It is powered by a 2.3-litre six-cylinder engine using Bosch K-Jetronic fuel-injection. It accelerates to in 8.7 seconds and has a top speed of . Transmissions 3-speed ZF 3HP22 automatic (318 and 320) 4-speed Getrag 242 manual 5-speed Getrag 245 manual, with either an overdrive fifth gear or close-ratio gearing (the latter available from 1976). Chassis and suspension With a wheelbase measuring , the lengths of the overhanging front and rear bodywork was minimal. The track measured at the front, and at the rear. The suspension incorporated rack and pinion steering and MacPherson strut suspension at the front, and semi-trailing arm type independent suspension at the rear. The rear suspension design causes camber changes, which can introduce "snap oversteer" at the handling limits. The power assisted brakes were discs on the front wheels, while the rear wheels had drum brakes (except the 323i model which had discs all round). Model year changes At the E21's release, three models were available: with 316 (1.6-litre), 318 (1.8-litre) and 320 (2.0-litre) versions of the BMW M10 four-cylinder engine. To differentiate between models, the 320 model came with dual headlights, while the 316 and 318 had single headlights. 1975 The fuel-injected 320i was introduced at the end of 1975. It has the M10 four-cylinder engine with Bosch K-Jetronic fuel injection, and a limited slip differential was available as an option. 1977 At the 1977 International Auto Show in Frankfurt, BMW unveiled its new variants of the E21, featuring the new BMW M20 six-cylinder engines (which were initially called "M60"). The four-cylinder 320 model was replaced with the 320/6, featuring a 2.0 litre version of the M20 engine. The new range-topping 323i model was introduced, featuring 2.3 L with , which gave the 323i a top speed of . The braking system was also upgraded, with the 323i featuring disc brakes on all wheels. Options include power steering, a 5-speed close-ratio 'dogleg' sport gearbox, and 25% limited slip differential. 1980 For the 1980 model year, the four-cylinder models were upgraded: the 1.8 L carburetted M10 unit was revised to produce and entered the market in the updated 316, while a fuel-injected version of the 1.8 L M10 was introduced in the 318i model (which replaced the carburetted 318 as the mid-range model). This fuel-injected 1.8 L M10 was also sold in Sweden with 320i badging (with a higher level of standard equipment to distinguish