Under the new engine coding system N54 engine is badged (it was rebadged):

N54 B30 U0

(and I expect V8 bi-turbo is coded N64 B44 U0, or N64 B44 M0).


U0

The letter tells us the power output. K = lowest power output, U = low power output, M = moderate power output, O = high power output, T = highest power output.
The number tells us the version. 0 = initial version 1 = first upgrade, 2 = second upgrade, 3 = ...).


B30

The letter tells us the type of energy source engine is using. B = gasoline, D = diesel, E = electricity, G = natural gas, H = hydrogen.

The 2-digit number tells us the displacement of the engine. 30 = 3.0L, 25 = 2.5L , 20 = 2.0L, 44 = 4.4L, 48 = 4.8L, etc.


N54

The letter tells us the generation of the engine. Eg. N = new generation, M = previous generation, S = sports generation.

The first number is a code telling us the number of cylinders. 4=4cyl, 5=6cyl, 6=8cyl, 7=12cyl, 8=10cyl.

The second number tells use the tech engine is using. 0 = prototype, 1 = SULEV/PZEV configuration , 2 = double VANOS + Valvetronic, 3 = Direct Injection Naturally Aspirated, 4 = Direct Injection Turbocharged, 5 = Double VANOS w/o Valvetronic, 7 = diesel engine turbocharged.




So, N54 B30 U0 tells us the current version (135i, 335i, 535i, 635i, X6 35i etc) is the lowest power output version!!!