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BMW S14B23 specs: 2.3L (140 ci) 4-cylinder, 93.4 x 84 mm (3.6772 x 3.3071 in) bore and stroke, 10.5:1 compression. Rated 192 hp, 1988–1991.
The BMW S14B23 is oversquare — the 3.6772" bore exceeds the 3.3071" stroke by 11.2% — 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 4 cylinders displaces 35.0 ci (574 cc).
10.5:1 is in the range that usually runs on pump premium.
4 factory variants share these dimensions, rated at 192 hp across 1988–1991.
| Displacement | 140 ci / 2.3 L |
|---|---|
| Bore | 3.6772" |
| Stroke | 3.3071" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 10.5:1 * |
| Bore/stroke ratio | 1.112 |
* Compression ratio from a single source; not yet cross-verified.
| Fuel type | gas |
|---|---|
| Advertised HP | 192 hp |
| Years | 1988–1991 |
| Bore/stroke character | 1.112 — 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 | 35.0 ci |
| Static compression | 10.5:1 — 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 |
|---|---|---|
| 1988 | 192 hp | S14B23 |
| 1989 | 192 hp | S14B23 |
| 1990 | 192 hp | S14B23 |
| 1991 | 192 hp | S14B23 |
1 factory vehicle, 1988–1991. Each year opens that model's engine table.