BMW Engine codes / naming convention explained

BMW engine code meanings

BMW engine codes contain an order of numbers and letters which represent specific technical information.  Although at first glance these numbers may seem random, they actually have a meaning.  This is very similar to a VIN or Vehicle Identification Number.  It is a way more manufacturers to record which version the vehicle has.

Understanding the meaning of how the engine codes are written will allow one to remember them easier and apply what they mean to other models.  These engine codes can also be important to the owner when finding replacement parts or learning more about the vehicle specifications.

In the tables below, the example engine code in the upper left hand corner is a typical engine naming convention.  The BOLD portion of the engine code is explained in each table.  The rows below show the different options and the meanings for these configurations.

It is important to note, the format below is for BMW engines created since the mid 1980's.  Previous generation motors had a simpler naming designation, M10 were 4 cylinders, M20 were small displacement 6 cylinders and M30s were large displacement 6 cylinders.  Since BMW vehicle production expanded greatly in the 1980s onward, many new engine variants were created and the basic engine naming convention of the past would simply no longer.  Introducing the naming convention below provide detailed information about the engine in a short format.

Make sure to check out the images below with the engine codes written in the bottom left corner.  See if you can decode the engine model and apply what you learned above.

BMW "B, M, N, P " & "S" Family Engine Code Meanings

Engine Family
  This letter denotes the general engine family it belongs.
B BMW modular engine designed after 2013
M BMW engine designed from mid-1980's thru 2001
N BMW engine designed after 2001
P BMW Motorsport racing engine (non-production)
S BMW Motorsport racing engine (production)
W An engine supplied by an external vendor
Number of Cylinders
3 Inline 3 cylinder
4 Inline 4 cylinder
5 Inline 6 cylinder
6 8 cylinder (V configuration)
7 12 cylinder (V configuration)
8 10 cylinder (V configuration)
Engine Variation
  This denotes a change to the basic engine concept from the clean slate "0" design. The numbers are sequential in development number but not necessarily a superseding motor. For example, the M52 is a fuel injected motor and the M51 is a diesel motor; both are based off the original design of the M50. However, the M52 is not a updated revision of the M51.
0 Original design.
1 thru 9 Sequential revisions.
Fuel Type
This letter denotes the type of fuel / power the engine runs on as well as engine mounting direction.
A Gasoline / Petrol, transverse mounted
B Gasoline / Petrol, longitudinally mounted
C Diesel, transverse mounted
D Diesel, longitudinally mounted
E Electric
G Natural gas
H Hydrogen
Engine Displacement
This two digit number denotes the engine displacement in liters.
30 3.0 liter
25 2.5 liter
18 1.8 liter
12 1.2 liter
Technical Update
  The TU designation means the engine had a "Technical Update", this means a significant change has been made. Not all engines get a "TU" designation.

BMW "N" Family Engine Code Differences

Performance Class
  On the newer BMW "N" family engines the 7th position of the engine code contains a letter which designates the performance class.
K Lowest
U Lower
M Middle
O Upper
T Top
S Super
Technical Update
  On the newer BMW "N" family engines the 8th position of the engine code contains a number which designates the technical version of the motor in sequential order to each update.  This new designation coding replaces the older style "TU" or technical update of the "M" family of engines.
0 New Development
1 thru 9 Redesign

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