Bore, stroke, displacement and compression for all 9 Mitsubishi Sirius engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 122–145 ci |
|---|---|
| Cylinders | 4 |
| Bore | 3.346–3.425" |
| Stroke | 3.465–3.937" |
| Compression | 8.5–10.5:1 |
| Advertised power | 101–286 hp |
| Years | 1996–2012 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| 4G69 | 145 ci | 3.4252" × 3.937" | 9.5:1 | 162 |
| 4G69 | 145 ci | 3.4252" × 3.937" | — | 162 |
| 4G64 | 143 ci | 3.4055" × 3.937" | 8.5:1 | 112 |
| 4G64 | 143 ci | 3.4055" × 3.937" | 9:1 | 138–145 |
| 4G64 | 143 ci | 3.4055" × 3.937" | — | 141–154 |
| 4G63 | 122 ci | 3.3465" × 3.4646" | 9:1 | 101 |
| 4G63 | 122 ci | 3.3465" × 3.4646" | 10.5:1 | 145 |
| 4G63T | 122 ci | 3.3465" × 3.4646" | 8.5:1 | 247 |
| 4G63T | 122 ci | 3.3465" × 3.4646" | 8.8:1 | 286 |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
Compression spans 8.5:1 to 10.5:1, so fuel requirements differ meaningfully between members — worth checking before assuming parts interchange.
5 of 9 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.