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Kia Smartstream G2.5 T-GDi G4KR specs: 2.5L (152.5 ci) 4-cylinder, 88.5 x 101.5 mm (3.4843 x 3.9961 in) bore and stroke, 10.5:1 compression. Rated 300 hp.
The Kia Smartstream G2.5 T-GDi G4KR is undersquare — the 3.9961" stroke exceeds the 3.4843" bore by 12.8% — a layout that trades peak RPM for leverage and torque low in the range. The 3.9961" stroke puts mean piston speed at 4,000 ft/min around 6,000 RPM, which is where a production bottom end is generally considered at its limit. Each of the 4 cylinders displaces 38.1 ci (625 cc).
10.5:1 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 16 engines in the Smartstream family, sitting between the 61.02 ci and 213.58 ci members. 2 factory variants share these dimensions, rated at 300 hp across 2022–2023.
| Displacement | 152.5 ci / 2.5 L |
|---|---|
| Bore | 3.4843" |
| Stroke | 3.9961" |
| Cylinders | 4 |
| Configuration | I4 |
| Compression ratio | 10.5:1 |
| Bore/stroke ratio | 0.872 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 300 hp |
| Years | 2022–2023 |
| Bore/stroke character | 0.872 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,996 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 38.1 ci |
| Static compression | 10.5:1 — 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 |
|---|---|---|
| 2022 | 300 hp | Smartstream G2.5 T-GDi G4KR |
| 2023 | 300 hp | Smartstream G2.5 T-GDi G4KR |
1 factory vehicle, 2022–2023. Each year opens that model's engine table.