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Infiniti KR20DDET specs: 2.0L (122 ci) 4-cylinder, 84 x 90.1 mm (3.3071 x 3.5472 in) bore and stroke, 14:1 compression. Rated 268 hp. DOHC.
The Infiniti KR20DDET is undersquare — the 3.5472" stroke exceeds the 3.3071" bore by 6.8% — a layout that trades peak RPM for leverage and torque low in the range. The 3.5472" stroke puts mean piston speed at 4,000 ft/min around 6,750 RPM, which is where a production bottom end is generally considered at its limit. Each of the 4 cylinders displaces 30.5 ci (500 cc).
14:1 on aluminum heads is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.
It is one of 4 engines in the KR family, the largest at 122 ci. Factory fitments include the Infiniti QX50, Infiniti QX55.
| Displacement | 122 ci / 2 L |
|---|---|
| Bore | 3.3071" |
| Stroke | 3.5472" |
| Cylinders | 4 |
| Compression ratio | 14:1 |
| Bore/stroke ratio | 0.932 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | DOHC |
| Fuel type | gas |
| Advertised HP | 268 hp |
| Bore/stroke character | 0.932 — undersquare — stroke exceeds bore, which favours low-end torque |
|---|---|
| Mean piston speed at 6,000 RPM | 3,547 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 30.5 ci |
| Static compression | 14:1 — high enough that pump premium or better is normally required |
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