See other engines in this family
The same engine also has a main page: Honda K20C1.
Acura K20A3 specs: 2.0L (121.9 ci) 4-cylinder, 86 x 86 mm (3.3858 x 3.3858 in) bore and stroke, 9.8:1 compression. Rated 155-160 hp, 2002–2006.
The Acura K20A3 is exactly square — 3.3858" bore and 3.3858" stroke are the same — which splits the difference between a high-revving layout and a torque layout. The 3.3858" stroke does not reach 4,000 ft/min of mean piston speed until about 7,100 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 30.5 ci (499 cc).
9.8:1 on aluminum heads is in the range that usually runs on pump premium; aluminum sheds heat faster than iron, which makes the same number a little more forgiving.
It is one of 13 engines in the Honda K-series family, the smallest at 121.9 ci. 5 factory variants share these dimensions, rated from 155 to 160 hp across 2002–2006.
| Displacement | 121.9 ci / 2 L |
|---|---|
| Bore | 3.3858" |
| Stroke | 3.3858" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 9.8:1 |
| Bore/stroke ratio | 1 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 155–160 hp |
| Years | 2002–2006 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 2002 | K20A3 net | 160 @ 6500 | 141 lb-ft @ 4000 | 9.8:1 |
| 2003 | K20A3 net | 160 @ 6500 | 141 lb-ft @ 4000 | 9.8:1 |
| 2004 | K20A3 net | 160 @ 6500 | 141 lb-ft @ 4000 | 9.8:1 |
| 2005 | K20A3 net | 160 @ 6500 | 141 lb-ft @ 4000 | 9.8:1 |
| 2006 | K20A3 net | 155 @ 6500 | 139 lb-ft | — |
Factory specification sheet.
| Bore/stroke character | 1.000 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,386 ft/min — conservative for a street engine |
| Displacement per cylinder | 30.5 ci |
| Static compression | 9.8:1 — in the range that usually runs on pump premium |
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 |
|---|---|---|
| 2002 | 160 hp | K20A3 |
| 2003 | 160 hp | K20A3 |
| 2004 | 160 hp | K20A3 |
| 2005 | 160 hp | K20A3 |
| 2006 | 155 hp | K20A3 |
2 factory vehicles, 2002–2006. Each year opens that model's engine table.