See other engines in this family
Mitsubishi G15B specs: 1.5L (92 ci) 4-cylinder, 75.5 x 82 mm (2.9724 x 3.2283 in) bore and stroke, 9.4:1 compression. Built 1985–1988.
The Mitsubishi G15B is undersquare — the 3.2283" stroke exceeds the 2.9724" bore by 7.9% — a layout that trades peak RPM for leverage and torque low in the range. The 3.2283" stroke does not reach 4,000 ft/min of mean piston speed until about 7,450 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 4 cylinders displaces 23.0 ci (377 cc).
9.4:1 is low by modern standards and generally happy on regular pump fuel.
It is one of 2 engines in the Mitsubishi 92ci family, all of them 92 ci — the differences between them are in compression, heads and rating, not displacement. 4 factory variants share these dimensions across 1985–1988.
| Displacement | 92 ci / 1.5 L |
|---|---|
| Bore | 2.9724" |
| Stroke | 3.2283" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 9.4:1 * |
| Bore/stroke ratio | 0.921 |
* Compression ratio from a single source; not yet cross-verified.
| Fuel type | gas |
|---|---|
| Years | 1985–1988 |
| Bore/stroke character | 0.921 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,228 ft/min — conservative for a street engine |
| Displacement per cylinder | 23.0 ci |
| Static compression | 9.4:1 — 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 |
|---|---|---|
| 1985 | — | G15B |
| 1986 | — | G15B |
| 1987 | — | G15B |
| 1988 | — | G15B |
1 factory vehicle, 1985–1988. Each year opens that model's engine table.