BMW N57 vs B57: The Differences, And Which BMWs Have Each Engine

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

N57 vs B57 at a glance

Stage 1 figures are typical figures from our tuning catalogue. Every car is mapped and measured on our dyno, and your printout shows exactly what yours makes.

Which BMWs have the B57?

Years are approximate and some models weren’t sold in every market. The quickest way to be sure is a reg check: enter your reg here and we’ll show the exact engine and what it makes tuned. Every B57 car above has its own page with figures, prices and booking: start at our BMW B57 remap page.

Which BMWs have the N57?

The N57 is in the F-series 330d, 335d, 430d, 435d, 530d, 535d, 640d, 730d and 740d, the F25 X3 and F26 X4 30d and 35d, the E70 and F15 X5 and the E71 and F16 X6, plus the earlier E90 325d and 330d. The full list by model and year is in our N57 engine guide. One trap: the E90-generation 335d used the older M57, not the N57.

How to tell which one your car has

Look at the chassis code. An F-series car (F10, F30, F15 and so on) with a six-cylinder diesel has the N57; a G-series car (G20, G30, G05 and so on) has the B57. Your V5C shows the model and first registration, and a reg check on Check My Car shows the engine for you.

How they tune

Both love a custom dyno map, and both benefit from xHP gearbox tuning on the ZF8 auto, which raises the torque limits so the gearbox doesn’t hold the engine back. The approach is the same: health check, custom map on our 4WD dyno and a before-and-after printout. See our 330d & 530d and 335d pages for N57 figures, and our 530d G30 and 430d write-ups for real dyno results.

B57s built from June 2020 have an encrypted ECU. We unlock it in-house on the same visit rather than posting it away; see ECU unlocking.

Which is more reliable?

Both are strong engines. The N57’s known weak points, such as the rear timing chain, swirl flaps and EGR, are covered in our N57 problems guide. The B57 is a newer design and its cars are younger, so they’ve had less time to show age-related faults. On either engine, servicing matters more than which one you have: fresh oil at sensible intervals and a healthy EGR and DPF.

N57 vs B57 FAQs

Is the B57 better than the N57?

It’s the newer, more efficient design and part of BMW’s modular engine family. Tuned, the two make similar power: around 330hp for a 30d and 390–400hp for a 35d or 40d on a typical Stage 1.

Is the B57 more reliable than the N57?

Both are strong. The N57’s weak points are well known; the B57 is younger, so it has had less time to show age-related faults. Servicing matters more than which engine you have.

Which BMWs have the B57 engine?

G-series six-cylinder diesels from 2015 on: the 30d, 40d, M40d, M340d and M440d models, the 2016 to 2020 quad-turbo M50d, M550d and 750d, and the diesel Ineos Grenadier.

How can I tell if my BMW has an N57 or a B57?

An F-series six-cylinder diesel has the N57 and a G-series has the B57. A reg check on Check My Car will confirm it.

What replaced the N57?

The B57, introduced in July 2015 and rolled out model by model until the N57 finished in 2019.

Can you remap a B57?

Yes. A typical Stage 1 takes a B57 30d to around 330hp and a 40d to around 400hp. Cars built from June 2020 have an encrypted ECU, which we unlock in-house on the same visit.

Whether yours is an N57 or a B57, we’ll get the most from it safely. Check your car or get a free quote.