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Mercedes-Benz M276 + electric motor specs: 3.5L (213 ci) 6-cylinder, 92.9 x 86 mm (3.6575 x 3.3858 in) bore and stroke, 12:1 compression. Rated 329 hp.
The Mercedes-Benz M276 + electric motor is oversquare — the 3.6575" bore exceeds the 3.3858" stroke by 8.0% — a layout that favors airflow and RPM over leverage at the crank. The 3.3858" stroke does not reach 4,000 ft/min of mean piston speed until about 7,100 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 35.5 ci (582 cc).
12:1 is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.
It is one of 4 engines in the Mercedes-Benz 213ci family, all of them 213 ci — the differences between them are in compression, heads and rating, not displacement. 3 factory variants share these dimensions, rated at 329 hp across 2013–2015.
| Displacement | 213 ci / 3.5 L |
|---|---|
| Bore | 3.6575" |
| Stroke | 3.3858" |
| Cylinders | 6 |
| Configuration | V6 |
| Compression ratio | 12:1 |
| Bore/stroke ratio | 1.08 |
| Fuel type | gas |
|---|---|
| Advertised HP | 329 hp |
| Years | 2013–2015 |
| Bore/stroke character | 1.080 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,386 ft/min — conservative for a street engine |
| Displacement per cylinder | 35.5 ci |
| Static compression | 12:1 — high enough that pump premium or better is normally required |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 2013 | 329 hp | M276 + electric motor |
| 2014 | 329 hp | M276 + electric motor |
| 2015 | 329 hp | M276 + electric motor |
1 factory vehicle, 2013–2015. Each year opens that model's engine table.