See other engines in this family
BMW M30B32 specs: 3.2L (196 ci) 6-cylinder, 89 x 86 mm (3.5039 x 3.3858 in) bore and stroke, 8.8:1 compression. Rated 181 hp, 1978–1984.
The BMW M30B32 is close to square: 3.5039" bore against 3.3858" stroke, within 3.5%, which splits the difference between a high-revving layout and a torque layout. 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 32.7 ci (535 cc).
8.8:1 is low by modern standards and generally happy on regular pump fuel.
7 factory variants share these dimensions, rated at 181 hp across 1978–1984.
| Displacement | 196 ci / 3.2 L |
|---|---|
| Bore | 3.5039" |
| Stroke | 3.3858" |
| Cylinders | 6 |
| Configuration | I6 |
| Compression ratio | 8.8:1 * |
| Bore/stroke ratio | 1.035 |
* Compression ratio from a single source; not yet cross-verified.
| Fuel type | gas |
|---|---|
| Advertised HP | 181 hp |
| Years | 1978–1984 |
| Bore/stroke character | 1.035 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,386 ft/min — conservative for a street engine |
| Displacement per cylinder | 32.7 ci |
| Static compression | 8.8:1 — low by modern standards, generally happy on regular pump fuel |
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 |
|---|---|---|
| 1978 | — | M30B32 |
| 1979 | — | M30B32 |
| 1980 | — | M30B32 |
| 1981 | — | M30B32 |
| 1982 | 181 hp | M30B32 |
| 1983 | 181 hp | M30B32 |
| 1984 | 181 hp | M30B32 |
3 factory vehicles, 1978–1984. Each year opens that model's engine table.