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Mercedes-Benz M112 specs: 3.2L (195 ci) 6-cylinder, 89.9 x 84 mm (3.5394 x 3.3071 in) bore and stroke, 10:1 compression. Rated 221 hp, 1998–2005.
The Mercedes-Benz M112 is oversquare — the 3.5394" bore exceeds the 3.3071" stroke by 7.0% — a layout that favors airflow and RPM over leverage at the crank. The 3.3071" stroke does not reach 4,000 ft/min of mean piston speed until about 7,250 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 32.5 ci (533 cc).
10:1 is in the range that usually runs on pump premium.
It is one of 5 engines in the Mercedes-Benz 195ci family, all of them 195 ci — the differences between them are in compression, heads and rating, not displacement. 13 factory variants share these dimensions, rated at 221 hp across 1998–2005.
| Displacement | 195 ci / 3.2 L |
|---|---|
| Bore | 3.5394" |
| Stroke | 3.3071" |
| Cylinders | 6 |
| Configuration | V6 |
| Compression ratio | 10:1 |
| Bore/stroke ratio | 1.07 |
| Fuel type | gas |
|---|---|
| Advertised HP | 221 hp |
| Years | 1998–2005 |
| Bore/stroke character | 1.070 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,307 ft/min — conservative for a street engine |
| Displacement per cylinder | 32.5 ci |
| Static compression | 10:1 — in the range that usually runs on pump premium |
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 |
|---|---|---|
| 1998 | 221 hp | M112 |
| 1999 | 221 hp | M112 |
| 2000 | 221 hp | M112 |
| 2001 | — | M112 |
| 2001 | 221 hp | M112 |
| 2002 | — | M112 |
| 2002 | 221 hp | M112 |
| 2003 | — | M112 |
| 2003 | 221 hp | M112 |
| 2004 | — | M112 |
| 2004 | 221 hp | M112 |
| 2005 | — | M112 |
| 2005 | 221 hp | M112 |
2 factory vehicles, 1998–2005. Each year opens that model's engine table.