BMW N57 vs B57: The Straight-Six Diesels Explained

BMW's 3.0-litre straight-six diesel is a legend, smooth, torquey and hugely tunable. Two generations power most of the cars we see: the older N57 and the newer B57. Here's how they differ and how each responds to tuning.

The N57 (2008–2019)

The N57 powered the 30d and 35d across the 3, 4, 5, 6 and 7 Series and the X models. It's the engine we've specialised in for over 14 years, we know every map parameter inside out. Single-turbo (30d) and twin-turbo (35d/40d) versions respond superbly to a Stage 1 tune, with a 335d reaching around 390bhp.

The B57 (2015 on)

The B57 replaced the N57 as part of BMW's modular engine family. It's more efficient and refined, with updated injection and emissions hardware, but shares the same tunable character, strong, safe gains from a custom map.

How they tune

Both love a custom dyno map, and both benefit from xHP gearbox tuning on the ZF8 auto. The approach is the same: health check, custom map on our 4WD dyno, before-and-after printout, original file kept.

Whether yours is an N57 or B57, we'll get the most from it safely. Get a free quote.