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Acura B17A1 specs: 1.7L (103.7 ci) 4-cylinder, 81 x 81.4 mm (3.1890 x 3.2047 in) bore and stroke, 9.7:1 compression. Rated 160 hp. Rod ratio and piston speed.
The Acura B17A1 is close to square: 3.189" bore against 3.2047" stroke, within 0.5%, which splits the difference between a high-revving layout and a torque layout. The 3.2047" stroke does not reach 4,000 ft/min of mean piston speed until about 7,500 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 25.9 ci (425 cc).
9.7:1 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 12 engines in the Honda B-series family, sitting between the 97 ci and 121.8 ci members. Factory fitments include the Acura Integra GS-R (DA9) (USDM).
| Displacement | 103.7 ci / 1.7 L |
|---|---|
| Bore | 3.189" |
| Stroke | 3.2047" |
| Cylinders | 4 |
| Compression ratio | 9.7:1 |
| Bore/stroke ratio | 0.995 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 160 hp |
| Bore/stroke character | 0.995 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,205 ft/min — conservative for a street engine |
| Displacement per cylinder | 25.9 ci |
| Static compression | 9.7:1 — in the range that usually runs on pump premium |
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