Article: How to read BMW engine and block codes and what they mean - B38K15T0 and M50B25TU examples

[Sticky]

Most readers here understand that we identify a BMW motor by its engine code. It is even how the forums are sorted here. It takes a bit more knowledge of BMW's than the casual BMW fan might be aware of so let's educate people on how and why BMW uses the engine codes that they use.

A popular past engine family for example in the BMW world is the M50 line of inline-6 motors. The full codename explains the differences in the M50 line. Look at this M50B25TU example:

M is the engine family or generation. 5 means it is an inline-6 engine. 0-9 are the variation. B means it is a gasoline engine. 25 is the engine size in liters in this example a 2.5 liter. TU stands for technical update.

Using a more modern example the BMW N63 twin turbo 4.4 liter V8 was updated and so there is an N63TU motor. We rarely use the full engine codes here as typing the whole thing out is tedious. If we did instead of writing N63 or N63TU we would have to write N63B44TU. Make sense?

Here is a graphical example that relates to the brand new B series engine generation:

This is the new 1.5 liter three cylinder turbo motor and you can see how the code changes to reflect this. We will just refer to it a B38.

BMW also does block codes and this complicates things and isn't necessary for general discussion but worth pointing out for those interested:

[seven11]

Man, I love this bimmerboost and boostaddict because of posts like this. I knew the engine codes from most manufacturers but not in details like this! Thanks sticky!

[auaq]

Will have to get used to these new names.

[Sticky]

Man, I love this bimmerboost and boostaddict because of posts like this. I knew the engine codes from most manufacturers but not in details like this! Thanks sticky!

Appreciated. My pleasure.

[Chavoos]

Whats the difference between the N54B30 and N54B30A

[Sticky]

Whats the difference between the N54B30 and N54B30A

Likely an update of some sort.