Caterpillar CG18 vs Perkins 4008TESI
The Caterpillar CG18 and Perkins 4008TESI are both natural gas generator engines in a similar power class. Both are rated at roughly 625 kVA. Displacement is 18.1 L versus 30.5 L. The table below compares their full specifications side by side.
| Specification | Caterpillar CG18 | Perkins 4008TESI |
|---|---|---|
| Headline rating | 625 kVA | 625 kVA |
| Standby (50 Hz) | — | — |
| Prime (50 Hz) | — | 500 kWe |
| Standby (60 Hz) | 500 kWe | — |
| Prime (60 Hz) | — | — |
| Displacement | 18.1 L | 30.5 L |
| Configuration | L6 | V8 |
| Cylinders | 6 | 8 |
| Rated speed | 1,800 RPM | 1,500 RPM |
| Fuel | Natural Gas | Natural Gas |
| Cooling | Liquid-Cooled | Liquid-Cooled |
| Emissions | U.S. EPA Stationary | Unregulated |
| Dry weight | — | — |
| Origin | United States | United Kingdom |
Choosing between Caterpillar CG18 and Perkins 4008TESI
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.