Saab 121ci specs: 90 x 78 mm (3.5433 x 3.0709 in) bore and stroke, shared by all 8 versions. Displacement, compression and factory ratings, plus rod ratio.
| Displacement | 121 ci |
|---|---|
| Cylinders | 4 |
| Bore | 3.543" |
| Stroke | 3.071" |
| Compression | 8.8–10.1:1 |
| Advertised power | 125–205 hp |
| Years | 1979–2002 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| B204L / B205L | 121 ci | 3.5433" × 3.0709" | 9.2:1 | — |
| B204R | 121 ci | 3.5433" × 3.0709" | 9.2:1 | — |
| B205R | 121 ci | 3.5433" × 3.0709" | 8.8:1 | 205 |
| B201 Turbo | 121 ci | 3.5433" × 3.0709" | — | 135 |
| B201 | 121 ci | 3.5433" × 3.0709" | 9.2:1 | — |
| B202 Turbo | 121 ci | 3.5433" × 3.0709" | 9:1 | 160 |
| B202 | 121 ci | 3.5433" × 3.0709" | 10.1:1 | 125 |
| B204L | 121 ci | 3.5433" × 3.0709" | 9.2:1 | — |
All are oversquare — bore larger than stroke, which favours revs over low-end torque.
Each engine page carries rod ratio, mean piston speed, bore/stroke character and cylinder head specs where published, and links into the calculators with its dimensions already filled in.