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BMW S38B36 specs: 3.5L (216 ci) 6-cylinder, 93.4 x 86 mm (3.6772 x 3.3858 in) bore and stroke, 10:1 compression. Rated 310 hp, 1991–1993.
The BMW S38B36 is oversquare — the 3.6772" bore exceeds the 3.3858" stroke by 8.6% — 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 36.0 ci (590 cc).
10:1 is in the range that usually runs on pump premium.
3 factory variants share these dimensions, rated at 310 hp across 1991–1993.
| Displacement | 216 ci / 3.5 L |
|---|---|
| Bore | 3.6772" |
| Stroke | 3.3858" |
| Cylinders | 6 |
| Configuration | I6 |
| Compression ratio | 10:1 * |
| Bore/stroke ratio | 1.086 |
* Compression ratio from a single source; not yet cross-verified.
| Fuel type | gas |
|---|---|
| Advertised HP | 310 hp |
| Years | 1991–1993 |
| Bore/stroke character | 1.086 — 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 | 36.0 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 |
|---|---|---|
| 1991 | 310 hp | S38B36 |
| 1992 | 310 hp | S38B36 |
| 1993 | 310 hp | S38B36 |
1 factory vehicle, 1991–1993. Each year opens that model's engine table.