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Porsche MA1.21 specs: 3.4L (209.7 ci) 6-cylinder, 97 x 77.5 mm (3.8189 x 3.0512 in) bore and stroke, 12.5:1 compression. Rated 310-330 hp, 2009–2012.
The Porsche MA1.21 is oversquare — the 3.8189" bore exceeds the 3.0512" stroke by 25.2% — a layout that favors airflow and RPM over leverage at the crank. The 3.0512" stroke does not reach 4,000 ft/min of mean piston speed until about 7,850 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 34.9 ci (573 cc).
12.5:1 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 14 engines in the MA1 family, sitting between the 165.1 ci and 231.9 ci members. 9 factory variants share these dimensions, rated from 310 to 330 hp across 2009–2012.
| Displacement | 209.7 ci / 3.4 L |
|---|---|
| Bore | 3.8189" |
| Stroke | 3.0512" |
| Cylinders | 6 |
| Compression ratio | 12.5:1 |
| Bore/stroke ratio | 1.252 |
| Valvetrain | DOHC |
|---|---|
| Fuel type | gas |
| Advertised HP | 310–330 hp |
| Years | 2009–2012 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2009 | MA1.21 net | 310 @ 6400 | 266 lb-ft @ 4400-5500 | 12.5:1 |
| 2009 | MA1.21 net | 320 @ 7200 | 273 lb-ft @ 4750 | 12.5:1 |
| 2010 | MA1.21 net | 310 @ 6400 | 266 lb-ft @ 4400-5500 | 12.5:1 |
| 2010 | MA1.21 net | 320 @ 7200 | 273 lb-ft @ 4750 | 12.5:1 |
| 2011 | MA1.21 net | 310 @ 6400 | 266 lb-ft @ 4400-5500 | 12.5:1 |
| 2011 | MA1.21 net | 320 @ 7200 | 273 lb-ft @ 4750 | 12.5:1 |
| 2012 | MA1.21 net | 310 @ 6400 | 266 lb-ft @ 4400-5500 | 12.5:1 |
| 2012 | MA1.21 net | 320 @ 7200 | 273 lb-ft @ 4750 | 12.5:1 |
Factory specification sheet.
| Bore/stroke character | 1.252 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,051 ft/min — conservative for a street engine |
| Displacement per cylinder | 34.9 ci |
| Static compression | 12.5:1 — 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 |
|---|---|---|
| 2009 | 310 hp | MA1.21 |
| 2009 | 320 hp | MA1.21 |
| 2010 | 310 hp | MA1.21 |
| 2010 | 320 hp | MA1.21 |
| 2011 | 310 hp | MA1.21 |
| 2011 | 320 hp | MA1.21 |
| 2012 | 310 hp | MA1.21 |
| 2012 | 320 hp | MA1.21 |
| 2012 | 330 hp | MA1.21 |
1 factory vehicle, 2009–2012. Each year opens that model's engine table.