Mercedes-Benz 243ci Specs: 83 x 92 mm

Mercedes-Benz 243ci specs: 83 x 92 mm (3.2677 x 3.6220 in) bore and stroke, shared by all 3 versions. Displacement, compression and factory ratings.

At a glance

Displacement	243 ci
Cylinders	8
Bore	3.268"
Stroke	3.622"
Compression	8.6:1
Advertised power	416–603 hp
Years	2015–2026

Engines in this family

Engine	Displacement	Bore × Stroke	CR	HP
M177	243 ci	3.2677" × 3.622"	8.6:1	469–603
M176	243 ci	3.2677" × 3.622"	—	416–496
M177 + rear e-motor	243 ci	3.2677" × 3.622"	8.6:1	—

Factory cars with a Mercedes-Benz 243ci

• Mercedes-Benz C-Class: 2015, M177; 2016, M177; 2017, M177; 2018, M177; 2019, M177; 2020, M177; 2021, M177; 2022, M177; 2023, M177
• Mercedes-Benz G-Class: 2016, M176; 2017, M176; 2018, M176; 2019, M176, 416 hp; 2019, M177, 577 hp; 2020, M176, 416 hp; 2020, M177, 577 hp; 2021, M176, 416 hp; 2021, M177, 577 hp; 2022, M176, 416 hp; 2022, M177, 577 hp; 2023, M176, 416 hp; 2023, M177, 577 hp; 2024, M176, 416 hp; 2024, M177, 577 hp; 2025, M177, 577 hp; 2026, M177
• Mercedes-Benz E-Class: 2018, M177, 603 hp; 2019, M177, 603 hp; 2020, M177, 603 hp; 2021, M177, 603 hp; 2023, M177, 603 hp
• Mercedes-Benz S-Class: 2018, M176; 2018, M177; 2019, M176; 2019, M177; 2020, M176; 2020, M177; 2021, M176; 2021, M177; 2021, M176, 496 hp; 2022, M176, 496 hp; 2023, M176, 496 hp; 2024, M176, 496 hp; 2025; 2025, M176, 496 hp; 2026; 2026, M176, 496 hp
• Mercedes-Benz SL: 2022, M177, 469 hp; 2022, M177, 577 hp; 2023, M177, 469 hp; 2023, M177, 577 hp; 2024, M177, 469 hp; 2024, M177, 577 hp; 2025; 2025, M177, 469 hp; 2025, M177, 577 hp; 2026; 2026, M177; 2026, M177, 469 hp; 2026, M177, 577 hp

What varies across the family

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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