Compared with its N20 predecessor, the B48 uses a more undersquare design, and an engine block using "closed-deck construction".

[3] Other features shared with the N20 include a twin-scroll turbocharger, direct injection, variable valve lift (Valvetronic) and variable valve timing (Double VANOS).

[4] The B48 engine was revised in 2018, dubbed "B48TU" ("Technical Update"), with notable changes and improvements; a new one-part timing chain as opposed to the earlier two-part, a new separate cooling circuits for the cylinder head and crankcase, and forged conrods and forged crankshaft is now 2.03 lb (1 kg) lighter due to the use of lighter materials and different machining.

[6][7] In the MINI Cooper S, a temporary overboost increases peak torque by 20 N⋅m (15 lb⋅ft) to 300 N⋅m (221 lb⋅ft).

[8] Introduced in May 2019 this engine features a reinforced crankshaft with larger main bearings and new pistons with a lower 9.5:1 compression ratio, this allows the engine to take more boost pressure from a larger turbocharger, which blows compressed air through a reworked intake tract.