For the "common mortal", the codes that brands give their engines look like a disorganized amalgamation of letters and numbers. However, there is a logic behind those codes, and the case of BMW engine codes is a good example.
The German brand has been using the same code scheme for several decades, with each letter and number present in the code corresponding to important information about the engine.
From the engine family to which the propellant belongs to the number of cylinders, passing by the type of fuel and even the number of evolutions that the engine has already undergone, there is a lot of information present in the codes by which BMW designates their names, you just need to know how to read them.
The “dictionary” of BMW engine codes
So that you can get an idea of how to decipher the codes that designate BMW engines, let's use the engine used by the BMW M4 as an example. Internally designated as S55B30T0 , what do you think each of the letters and numbers used by BMW to designate this six-cylinder in-line mean?S55B30T0
The first letter always represents the “engine family”. In this case, the “S” means that the engine was developed by the M division of BMW.
- M — engines developed before 2001;
- N — engines developed after 2001;
- B — engines developed from 2013 onwards;
- S — series production engines developed by BMW M;
- P — competition engines developed by BMW M;
- W — engines sourced from suppliers outside BMW.
S55B30T0
The second digit designates the number of cylinders. And before you start saying we can't count, know that the number doesn't always correspond to the exact number of cylinders.- 3 — 3-cylinder in-line engine;
- 4 — in-line 4-cylinder engine;
- 5 — 6-cylinder in-line engine;
- 6 — V8 engine;
- 7 — V12 engine;
- 8 — V10 engine;
S55B30T0
The third character in the code represents the number of evolutions (changes in injection, turbos, etc.) that the engine has already undergone since its initial development. In this case, the number “5” means that this engine has already received five upgrades since it was developed.
S55B30T0
The fourth character in the code indicates the type of fuel the engine uses and whether it is mounted transversely or longitudinally. In this case, the "B" means that the engine uses gasoline and is mounted longitudinally- A — Gasoline engine mounted in a transverse position;
- B — gasoline engine in longitudinal position;
- C — Diesel engine in transverse position;
- D — Diesel engine in longitudinal position;
- E — electric motor;
- G — natural gas engine;
- H — hydrogen;
- K — Gasoline engine in horizontal position.
S55B30T0
The two digits (fifth and sixth characters) correspond to displacement. In this case, as the engine is 3000 cm3 or 3.0 l, the number “30” appears. If it were, for example, a 4.4 l (V8) the number used would be “44”.
S55B30T0
The penultimate character defines the “performance class” to which the engine corresponds.- 0 — new development;
- K — lowest performance class;
- U — low performance class;
- M — middle class of performance;
- O — high performance class;
- T — top performance class;
- S — super performance class.
S55B30T0
The latter character represents a significant new technical development — for example, when engines moved from VANOS to dual VANOS (variable valve timing) — essentially, the move to a new generation. In this case the number “0” means that this engine is still in its first generation. If it did, for example, the number “4” meant that the engine would be in its fifth generation.
This last character ended up replacing the letters “TU” of “Technical Update” that we can find in older engines of the Bavarian brand.
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