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Volkswagen MV specs: 2.1L (129 ci) 4-cylinder, 94 x 76 mm (3.7008 x 2.9921 in) bore and stroke. Rated 90-95 hp, 1986–1991.
The Volkswagen 129ci (MV) is oversquare — the 3.7008" bore exceeds the 2.9921" stroke by 23.7% — a layout that favors airflow and RPM over leverage at the crank. The 2.9921" stroke does not reach 4,000 ft/min of mean piston speed until about 8,000 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 32.3 ci (528 cc).
6 factory variants share these dimensions, rated from 90 to 95 hp across 1986–1991.
| Displacement | 129 ci / 2.1 L |
|---|---|
| Bore | 3.7008" |
| Stroke | 2.9921" |
| Cylinders | 4 |
| Bore/stroke ratio | 1.237 |
| Fuel type | gas |
|---|---|
| Advertised HP | 90–95 hp |
| Years | 1986–1991 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 1991 | MV net | 90 @ 4800 * | — | — |
Factory specification sheet. * Not yet cross-verified.
| Bore/stroke character | 1.237 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,992 ft/min — conservative for a street engine |
| Displacement per cylinder | 32.3 ci |
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 |
|---|---|---|
| 1986 | 95 hp | MV |
| 1987 | 95 hp | MV |
| 1988 | 90 hp | MV |
| 1989 | 90 hp | MV |
| 1990 | 90 hp | MV |
| 1991 | 90 hp | MV |
1 factory vehicle, 1986–1991. Each year opens that model's engine table.