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Porsche M97.20 specs: 2.7L (164 ci) 6-cylinder, 85.5 x 78 mm (3.3661 x 3.0709 in) bore and stroke, 11.3:1 compression. Rated 245 hp, 2007–2008.
The Porsche M97.20 is oversquare — the 3.3661" bore exceeds the 3.0709" stroke by 9.6% — a layout that favors airflow and RPM over leverage at the crank. The 3.0709" stroke does not reach 4,000 ft/min of mean piston speed until about 7,800 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 27.3 ci (448 cc).
11.3:1 is high enough that pump premium or better is normally required.
It is one of 4 engines in the Porsche 164ci family, all of them 164 ci — the differences between them are in compression, heads and rating, not displacement. 2 factory variants share these dimensions, rated at 245 hp across 2007–2008.
| Displacement | 164 ci / 2.7 L |
|---|---|
| Bore | 3.3661" |
| Stroke | 3.0709" |
| Cylinders | 6 |
| Compression ratio | 11.3:1 |
| Bore/stroke ratio | 1.096 |
| Fuel type | gas |
|---|---|
| Firing order | 1-6-2-4-3-5 |
| Advertised HP | 245 hp |
| Years | 2007–2008 |
| Bore/stroke character | 1.096 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,071 ft/min — conservative for a street engine |
| Displacement per cylinder | 27.3 ci |
| Static compression | 11.3:1 — 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 |
|---|---|---|
| 2007 | 245 hp | M97.20 |
| 2008 | 245 hp | M97.20 |
1 factory vehicle, 2007–2008. Each year opens that model's engine table.