BMW N52 330i E90 N52B30 engine

BMW N52 is a naturally aspirated straight-6 petrol engine which was produced from 2004 to 2015. The N52 replaced the BMW M54 and debuted on the E90 3 Series and E63 6 Series.

The N52 was the first water-cooled engine to use magnesium/aluminium composite construction in the engine block. It was also listed as one of Ward's 10 Best Engines in 2006 and 2007.

In European markets, the N52 began to be phased out in favor of its direct injected version, the BMW N53 in 2007. Markets such as the United States, Canada, Australia and Malaysia retained the N52 as the N53 was deemed unsuitable due to the high sulphur content of local fuel.

The engine is equipped with a dual overhead cam 24 valve cylinder head and the crankshaft is held in place with 36 main bearing cap bolts. The static compression ratio is 12.5:1 advertised, requiring the use of 100 RON (94 AKI) fuel.

The N52 and N53 are the last naturally aspirated straight-six engines produced by BMW, ending a history of continuous production of this engine configuration since the BMW M30 in 1968. In 2011, the N52 began to be replaced by the BMW N20 turbocharged four-cylinder engine. N52 production ceased in 2015. Unlike its predecessors, there is no BMW M version of the N52.

N52B30

The 3.0 L (183 cu in) models of the N52 have a bore of 85 mm (3.35 in), a stroke of 88 mm (3.46 in) and a compression ratio of 10.7:1. Variations in power output are often due to different intake manifolds and variations of engine management software.