ENGINE MASTER NORMALIZATION METHODOLOGY

Introduced: редакционная глава — 2026-08-13 Status: mandatory for all later engine passes.

1. Why Stage 4 is separate from the model index

A badge is not an engine code. A displacement is not an engine code. Two cars with the same badge can have different architectures, emissions calibrations, injection systems, catalyst states or output revisions. Conversely, one engine architecture may span many model names. ENGINE MASTER therefore normalizes engine/revision states, not marketing badges.

2. Row identity

A new row is required when at least one of these materially changes:

• official engine code/family;
• displacement;
• aspiration or turbo arrangement;
• fuel/injection system where the change creates a factory calibration phase;
• catalyst/emissions calibration with a different published output;
• cylinder head / valve architecture;
• VANOS / Valvetronic state;
• published power or torque revision;
• market calibration where BMW publishes a different rating;
• hybrid/electric component architecture in later passes.

A model-name change alone does not create an engine row if the technical state is unchanged.

3. Historical nomenclature is time-dependent

BMW's own historical engine documentation uses period designations that can collide with later familiar names:

• the 1933 BMW 303 six is M78;
• the 1952 BMW 501 six is M337;
• the new large six introduced in 1968 is documented as M06; after nomenclature reorganisation the family became known as M30;
• BMW's 1971 3.0-litre carburetted and injected sixes are described in the historical source as M21 and M20;
• the compact six introduced in 1977 is documented as M60, later renamed M20;
• the 1980 745i turbo is M102, followed by M106;
• the BMW M1 six is M88 / M88/1 depending the BMW historical document, while the M635CSi/M5 road evolution is M88/3.

Therefore a modern family label may be stored in Family / lineage, while Engine code preserves the source-era identifier or an explicit alias note. The database does not retroactively rewrite BMW's historical nomenclature.

4. Unit policy

The project-wide HISTORICAL-UNIT-POLICY.md applies.

• PS, hp and bhp are not treated as interchangeable labels.
• kW is entered only when BMW publishes it directly.
• historical localized pages with suspicious same-number PS/bhp are flagged rather than mathematically “fixed”.
• calculated values can be added only in a future explicitly labelled calculated field.

5. Unknown codes

UNVERIFIED means the current primary-source set does not justify a canonical factory code. It must not be replaced by an enthusiast convention merely because the convention is plausible. This is especially important for:

• pre-war application codes;
• 1950s BMW light-alloy V8 revisions;
• application suffixes inside M10/M30;
• market-specific M/S engine calibrations.

6. Hybrid and EV rule

Later Stage 4 passes must keep separate:

1. combustion-engine output;
2. electric-motor output;
3. battery usable/gross capacity;
4. combined system output;
5. boost/temporary maximum output where BMW publishes it separately.

No PHEV or BEV row may use a single “engine power” field to hide those distinctions.

7. Source hierarchy

1. BMW contemporary technical data / homologation material;
2. BMW Group Classic / BMW Group Archive;
3. BMW PressClub historical technical publications;
4. BMW M official heritage material;
5. independent period tests only for fields explicitly marked TESTED;
6. secondary sources only as gap-finders, not as final engine-code authority.