The four-cylinder engine was upgraded from the BMW M10 to the BMW M40 and various other mechanical changes were made. Rust protection was improved with the update. Body styles In addition to the two-door sedan and Baur convertible body styles of its E21 predecessors, the E30 later also became available as a four-door sedan and five-door station wagon (marketed as "Touring"). The Touring body style began life as a prototype built by BMW engineer Max Reisböck in his friend's garage in 1984 and began production in 1987. The factory convertible version began production in 1985, with the Baur convertible conversions remaining available alongside it. Engines Initially, the E30 used carryover four-cylinder (M10) and six-cylinder (M20) petrol engines from its E21 predecessor. Over the production run, new families of four-cylinder petrol engines were introduced and the six-cylinder engine received various upgrades. A six-cylinder diesel engine was introduced, in both naturally aspirated and turbocharged forms. Factory specifications are shown below. Four-cylinder petrol At the launch of the E30 range in 1982, the 316 used a 1766 cc version of the M10 fed by a carburetor and producing . The 318i had the same M10 engine, but with Bosch L-Jetronic fuel-injection, increasing power to while also improving fuel economy. The 1987 Series 2 update introduced a new four-cylinder engine: the M40, which used Bosch Motronic fuel-injection. In the 318i, a version of the M40 was used. The 316i model replaced the 316, using a version of the M40. The 318iS was released in 1989, using the new M42 engine and only being available with two doors. This is the most modern engine available in the E30 range, incorporating DOHC, the updated Bosch Motronic 1.7, hydraulic valve adjusters and coil-on-plug ignition. In some markets, the M42 engine was used in the 318i/318iC models, instead of the M40. The M3 is powered by the S14 engine, a high-revving four-cylinder engine. Six-cylinder petrol At the launch of the E30 range, the six-cylinder models consisted of the 320i, which had a version of the M20 producing , and the 323i, with a M20 producing , both using Bosch L-Jetronic fuel injection. These models were not sold in North America, presumably for emissions reasons. In 1985, the 2.3 L engine was replaced with a 2.5 L version of the M20, which produced and used Bosch Motronic fuel injection. This engine was available in the 325i variants, including the