Infiniti QR specs: 89 x 100 mm (3.5039 x 3.9370 in) bore and stroke, shared by all 2 versions. Displacement, compression and factory ratings, plus rod ratio.
| Displacement | 152–152.5 ci |
|---|---|
| Cylinders | 4 |
| Bore | 3.504" |
| Stroke | 3.937" |
| Compression | 9.1–9.5:1 |
| Advertised power | 175–250 hp |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| QR25DE | 152.5 ci | 3.5039" × 3.937" | 9.5:1 | 175 |
| QR25DER | 152 ci | 3.5039" × 3.937" | 9.1:1 | 230–250 |
All 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.