Bore, stroke, displacement and compression for all 2 Hyundai Sirius engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 109.8–121.9 ci |
|---|---|
| Cylinders | 4 |
| Bore | 3.189–3.346" |
| Stroke | 3.465" |
| Compression | 9.2:1 |
| Advertised power | 105–120 hp |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| G4CP | 121.9 ci | 3.3465" × 3.4646" | 9.2:1 | 120 |
| Sirius · 3.189" × 3.465" · 9.2:1 | 109.8 ci | 3.189" × 3.4646" | 9.2:1 | 105–113 |
Stroke is constant at 3.4646" across the family — the displacement spread comes from bore, so these share a crank and differ in the block.
1 of 2 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.