BMW B38 Engine (2014)

Available from 2014, the BMW B38 was a three-cylinder turbocharged petrol engine. The B38 was a part of BMW’s modular family of engines which included the four-cylinder B48 petrol engine, the three-cylinder B37 diesel and four-cylinder B47 diesel engines. For three- and four-cylinder engines of the same fuel type, around 60 per cent of components were shared; for engines of different fuel types, around 40 per cent of components were shared. All four engines were manufactured on a single assembly line at BMW’s Steyr plant in Austria and production was estimated at 5500 engines per day.

The B38 engine had an aluminium block and cylinder head, a single-scroll turbocharger, direct fuel injection, double overhead camshafts (chain-driven), variable camshaft timing, four valves per cylinder, variable intake valve lift (BMW’s ‘Valvetronic’) and a compression ratio of 11.0:1.

In an industry first, the radial-axial Continental turbocharger for the B38 engine had a water-cooled turbine housing that was produced from cast aluminium. Compared to a typical heat-resistant cast-steel turbocharger housing, the cast aluminium housing was around 30 per cent lighter and cheaper to produce; its design was also claimed to reduce load on the catalytic converter.