See other engines in this family
The same engine also has a main page: Honda F23A1.
Acura F23A1 specs: 2.289L (137.9 ci) 4-cylinder, 86 x 97 mm (3.3858 x 3.8189 in) bore and stroke, 9.3:1 compression. Rated 150 hp, 1998–1999.
The Acura F23A1 is undersquare — the 3.8189" stroke exceeds the 3.3858" bore by 11.3% — a layout that trades peak RPM for leverage and torque low in the range. The 3.8189" stroke puts mean piston speed at 4,000 ft/min around 6,300 RPM, which is where a production bottom end is generally considered at its limit. Each of the 4 cylinders displaces 34.5 ci (565 cc).
9.3:1 on aluminum heads is low by modern standards and generally happy on regular pump fuel.
It is one of 5 engines in the Honda H-series family, the largest at 137.9 ci. 2 factory variants share these dimensions, rated at 150 hp across 1998–1999.
| Displacement | 137.9 ci / 2.289 L |
|---|---|
| Bore | 3.3858" |
| Stroke | 3.8189" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 9.3:1 * |
| Bore/stroke ratio | 0.887 |
* Compression ratio from a single source; not yet cross-verified.
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Redline | 6,300 rpm (factory limit) |
| Advertised HP | 150 hp |
| Years | 1998–1999 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 1998 | F23A1 net | 150 @ 5700 * | 152 lb-ft @ 4800 * | 9.3:1 * |
| 1999 | F23A1 net | 150 @ 5700 * | 152 lb-ft @ 4800 * | 9.3:1 * |
Factory specification sheet. * Not yet cross-verified.
| Bore/stroke character | 0.887 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,819 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 34.5 ci |
| Static compression | 9.3:1 — 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 |
|---|---|---|
| 1998 | 150 hp | F23A1 |
| 1999 | 150 hp | F23A1 |
2 factory vehicles, 1998–2002. Each year opens that model's engine table.