Bore, stroke, displacement and compression for all 5 Saturn GM Ecotec engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 122–145 ci |
|---|---|
| Cylinders | 4 |
| Bore | 3.386–3.465" |
| Stroke | 3.386–3.858" |
| Compression | 9.2–11.2:1 |
| Advertised power | 135–260 hp |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| LAF | 145 ci | 3.4646" × 3.8583" | 11.2:1 | 164 |
| LE5 | 145 ci | 3.4646" × 3.8583" | 10.4:1 | 169–170 |
| L61 | 134 ci | 3.3858" × 3.7244" | 10:1 | 135 |
| LSJ | 122 ci | 3.3858" × 3.3858" | 9.5:1 | 205 |
| 20 LPF Ecotec Turbo | 122 ci | 3.3858" × 3.3858" | 9.2:1 | 260 |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
Compression spans 9.2:1 to 11.2:1, so fuel requirements differ meaningfully between members — worth checking before assuming parts interchange.
3 of 5 are undersquare — stroke larger than bore, favouring torque low in the range.
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.