BMW 122ci Engine Specs

Bore, stroke, displacement and compression for all 7 BMW 122ci engines, compared side by side. Plus rod ratio and head specs where published.

At a glance

Displacement	122 ci
Cylinders	4
Bore	3.228–3.307"
Stroke	3.543–3.724"
Compression	10.0–16.5:1
Advertised power	180–322 hp
Years	2012–2026

Engines in this family

Engine	Displacement	Bore × Stroke	CR	HP
N20B20	122 ci	3.3071" × 3.5472"	10:1	180–308
B48B20	122 ci	3.2283" × 3.7244"	10.5:1	180–322
B46B20	122 ci	3.228" × 3.724"	10.2:1	248–288
B46B20 / B48B20	122 ci	3.2283" × 3.7244"	10.2:1	248
B48A20	122 ci	3.2283" × 3.7244"	11:1	189
B48	122 ci	3.2283" × 3.7244"	11.1:1	201
N47D20	122 ci	3.3071" × 3.5433"	16.5:1	180

Factory cars with a BMW 122ci

• BMW 3 Series / M3: 2012, 240 hp; 2013, 180 hp; 2013, 240 hp; 2014, 180 hp; 2014, 240 hp; 2015, 180 hp; 2015, 240 hp; 2016, 180 hp; 2016, 240 hp; 2016, 248 hp; 2017, 180 hp; 2017, 248 hp; 2018, 180 hp; 2018, 248 hp; 2019, 248 hp; 2019, 255 hp; 2020, 255 hp; 2021, 255 hp; 2021, 288 hp; 2022, 255 hp; 2022, 288 hp; 2023, 255 hp; 2023, 288 hp; 2024, 255 hp; 2024, 288 hp; 2025, 255 hp; 2026, 255 hp
• BMW 5 Series: 2012; 2013; 2014; 2015; 2016; 2017, 248 hp; 2018, 248 hp; 2019, 248 hp; 2020, 248 hp; 2021, 248 hp; 2021, 288 hp; 2022, 248 hp; 2022, 288 hp; 2023, 248 hp; 2023, 288 hp; 2024, 255 hp; 2025, 255 hp; 2026, 255 hp
• BMW Z4: 2012, 240 hp; 2013, 240 hp; 2014, 240 hp; 2015, 240 hp; 2016, 240 hp; 2019, 255 hp; 2020, 255 hp; 2021, 255 hp; 2022, 255 hp; 2023, 255 hp; 2024, 255 hp; 2025, 255 hp; 2026, 255 hp
• BMW 2 Series: 2014; 2015; 2016; 2017, 248 hp; 2018, 248 hp; 2019, 248 hp; 2020, 248 hp; 2021, 248 hp; 2022; 2023; 2024; 2025; 2026
• MINI Mini Cooper: 2014, 189 hp; 2015; 2016; 2017; 2018; 2019; 2020; 2021; 2022; 2023; 2024; 2025, B48, 201 hp
• BMW X5: 2016, 308 hp; 2017, 308 hp; 2018, 308 hp
• BMW 7 Series: 2017, 322 hp; 2018, 322 hp; 2019, 322 hp

What varies across the family

Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.

Compression spans 10:1 to 16.5:1, so fuel requirements differ meaningfully between members — worth checking before assuming parts interchange.

All are undersquare — stroke larger than bore, favouring torque low in the range.

Each engine page carries rod ratio, mean piston speed, bore/stroke character and cylinder head specs where published, and links into the calculators with its dimensions already filled in.

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