Cummins QSB3.9-G33 vs SDEC 4Z3.2-G12
Compare Cummins QSB3.9-G33 and SDEC 4Z3.2-G12 by recorded output, operating duty, frequency and engine specifications. Their listed displacements are 3.9 L and 3.2 L, respectively. Start with the same duty and frequency, then check each model’s source and package conditions. These records alone do not establish interchangeability.
| Specification | Cummins QSB3.9-G33 | SDEC 4Z3.2-G12 |
|---|---|---|
| Standby electrical (50 Hz) | 38 kWe | 38 kWe |
| Prime electrical (50 Hz) | 30 kWe | 34 kWe |
| Standby electrical (60 Hz) | Not listed | 38 kWe |
| Prime electrical (60 Hz) | Not listed | 34 kWe |
| Displacement | 3.9 L | 3.2 L |
| Configuration | L4 | L4 |
| Cylinders | 4 | 4 |
| Recorded engine speed | 1,500 RPM | 1,500 RPM |
| Fuel | Diesel | Diesel |
| Cooling | Liquid-Cooled | Liquid-Cooled |
| Recorded emissions classification | Unregulated | China National Stage II / Unregulated |
| Dry weight | Not listed | Not listed |
| Origin | China | China |
Compare matching ratings
Read across a row to compare the same operating duty and frequency. kWe is electrical output; mechanical kW is power at the engine shaft. kVA is apparent electrical power and is shown only when kWe is missing, without converting it. “Not listed” means the record lacks that rating, not zero output. Continuous and prime duties are kept separate. Check source documents, units and site conditions before comparing values.
An emissions classification in the catalog is not proof of certification for your engine or installation. Confirm the exact model, applicable documents and generator configuration.
Cummins QSB3.9-G33: Review the model record and available supporting documents
SDEC 4Z3.2-G12: Review the model record and available supporting documents
Choosing between Cummins QSB3.9-G33 and SDEC 4Z3.2-G12
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.