Bore, stroke, displacement and compression for all 2 Porsche 9A2 Evo engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 121.3–243.9 ci |
|---|---|
| Cylinders | 4, 6 |
| Bore | 3.583–4.016" |
| Stroke | 3.008–3.209" |
| Compression | 9.5–13.3:1 |
| Advertised power | 300–502 hp |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| DRU | 243.9 ci | 4.0157" × 3.2087" | 13.3:1 | 502 |
| 20 9A2 718 | 121.3 ci | 3.5827" × 3.0079" | 9.5:1 | 300 |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
Compression spans 9.5:1 to 13.3:1, so fuel requirements differ meaningfully between members — worth checking before assuming parts interchange.
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.