See other engines in this family
Kia G4JS specs: 2.4L (144 ci) 4-cylinder, 88 x 97 mm (3.4646 x 3.8189 in) bore and stroke, 10:1 compression. Built 2006. Used in the Kia Optima / K5. DOHC.
The Kia G4JS is undersquare — the 3.8189" stroke exceeds the 3.4646" bore by 9.3% — 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 36.0 ci (590 cc).
10:1 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 5 engines in the Kia 144ci family, all of them 144 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 144 ci / 2.4 L |
|---|---|
| Bore | 3.4646" |
| Stroke | 3.8189" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 10:1 |
| Bore/stroke ratio | 0.907 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Years | 2006 |
| Bore/stroke character | 0.907 — 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 | 36.0 ci |
| Static compression | 10:1 — in the range that usually runs on pump premium |
Each link opens the calculator with this engine's specs already filled in.
1 factory vehicle, 2006. Each year opens that model's engine table.