Audi 131ci specs: 79.5 x 86.4 mm (3.1299 x 3.4016 in) bore and stroke, shared by all 5 versions. Displacement, compression and factory ratings.
| Displacement | 131 ci |
|---|---|
| Cylinders | 5 |
| Bore | 3.130" |
| Stroke | 3.402" |
| Compression | 8.0–8.3:1 |
| Years | 1978–1985 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| 2.1 (2144 cc) | 131 ci | 3.1299" × 3.4016" | — | — |
| WC / WE | 131 ci | 3.1299" × 3.4016" | 8:1 | — |
| WK | 131 ci | 3.1299" × 3.4016" | — | — |
| KH | 131 ci | 3.1299" × 3.4016" | 8.3:1 | — |
| WX | 131 ci | 3.1299" × 3.4016" | — | — |
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.