Caterpillar 3408 vs Cummins QSG12-G4
The Caterpillar 3408 and Cummins QSG12-G4 are both diesel generator engines in a similar power class. Both are rated at roughly 456 kVA. Displacement is 18 L versus 11.8 L. The table below compares their full specifications side by side.
| Specification | Caterpillar 3408 | Cummins QSG12-G4 |
|---|---|---|
| Headline rating | 456 kVA | 455 kVA |
| Standby (50 Hz) | 365 kWe | 364 kWe |
| Prime (50 Hz) | 330 kWe | 333 kWe |
| Standby (60 Hz) | 440 kWe | 418 kWe |
| Prime (60 Hz) | 400 kWe | 383 kWe |
| Displacement | 18 L | 11.8 L |
| Configuration | V8 | L6 |
| Cylinders | 8 | 6 |
| Rated speed | 1,500 / 1,800 RPM | 1,500 / 1,800 RPM |
| Fuel | Diesel | Diesel |
| Cooling | Liquid-Cooled | Liquid-Cooled |
| Emissions | U.S. EPA Tier 2 | Unregulated |
| Dry weight | — | 1110 kg |
| Origin | United States | China |
Choosing between Caterpillar 3408 and Cummins QSG12-G4
Use this comparison as an engineering shortlist, then confirm the complete generator package against load profile, voltage, 50/60 Hz frequency, duty class, emissions rules, cooling margin, altitude, ambient temperature, enclosure design, controller features, and alternator sizing. The Caterpillar 3408 has the higher headline kVA rating in this pair, but site conditions and duty cycle can still change the final recommendation.