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Volkswagen 1Z / AHU specs: 1.9L (116 ci) 4-cylinder, 79.5 x 95.5 mm (3.1299 x 3.7598 in) bore and stroke, 19.5:1 compression. Built 1996–1997.
The Volkswagen 1Z / AHU is undersquare — the 3.7598" stroke exceeds the 3.1299" bore by 16.8% — a layout that trades peak RPM for leverage and torque low in the range. The 3.7598" stroke puts mean piston speed at 4,000 ft/min around 6,400 RPM, which is where a production bottom end is generally considered at its limit. Each of the 4 cylinders displaces 29.0 ci (475 cc).
19.5:1 is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.
It is one of 3 engines in the Volkswagen 116ci family, all of them 116 ci — the differences between them are in compression, heads and rating, not displacement. 2 factory variants share these dimensions across 1996–1997.
| Displacement | 116 ci / 1.9 L |
|---|---|
| Bore | 3.1299" |
| Stroke | 3.7598" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 19.5:1 * |
| Bore/stroke ratio | 0.832 |
* Compression ratio from a single source; not yet cross-verified.
| Fuel type | gas |
|---|---|
| Years | 1996–1997 |
| Bore/stroke character | 0.832 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,760 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 29.0 ci |
| Static compression | 19.5:1 — high enough that pump premium or better is normally required |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 1996 | — | 1Z / AHU |
| 1997 | — | 1Z / AHU |
1 factory vehicle, 1996–1998. Each year opens that model's engine table.