See other engines in this family
Porsche 901/36, 901/37, 901/38, 901/39 specs: 2.0L (121 ci) 6-cylinder, 80 x 66 mm (3.1496 x 2.5984 in) bore and stroke, 8.6:1 compression. Rated 110 hp.
The Porsche 901/36, 901/37, 901/38, 901/39 is oversquare — the 3.1496" bore exceeds the 2.5984" stroke by 21.2% — a layout that favors airflow and RPM over leverage at the crank. The 2.5984" stroke does not reach 4,000 ft/min of mean piston speed until about 9,250 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 20.2 ci (330 cc).
8.6:1 is low by modern standards and generally happy on regular pump fuel.
It is one of 3 engines in the Porsche 121ci family, all of them 121 ci — the differences between them are in compression, heads and rating, not displacement. 3 factory variants share these dimensions, rated at 110 hp across 1970–1972.
| Displacement | 121 ci / 2 L |
|---|---|
| Bore | 3.1496" |
| Stroke | 2.5984" |
| Cylinders | 6 |
| Compression ratio | 8.6:1 |
| Bore/stroke ratio | 1.212 |
| Fuel type | gas |
|---|---|
| Advertised HP | 110 hp |
| Years | 1970–1972 |
| Bore/stroke character | 1.212 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,598 ft/min — conservative for a street engine |
| Displacement per cylinder | 20.2 ci |
| Static compression | 8.6:1 — low by modern standards, generally happy on regular pump fuel |
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 |
|---|---|---|
| 1970 | 110 hp | 901/36, 901/37, 901/38, 901/39 |
| 1971 | 110 hp | 901/36, 901/37, 901/38, 901/39 |
| 1972 | 110 hp | 901/36, 901/37, 901/38, 901/39 |
1 factory vehicle, 1970–1972. Each year opens that model's engine table.