The S58, a development of the already-prolific B58 3.0-litre engine, brings with it an impressive set of numbers that should translate into a similarly impressive M3. ... S58's maximum engine speed a respectable 7200rpm, although this is down 100rpm on S55. More importantly, in Competition spec, S58's specific power a stonking 125kW/litre. The B58 engine will replace the N55 engine throughout their vehicle lineup. Let’s examine what is new with the BMW B58 engine and what the differences are between the N55 and B58 engines. While this list is not all inclusive we will do our best to point out the significant changes. What has stayed the same. Normally, we look at what has.