Overview#
The Blue Star VD550-04FT4MP is a 550-kilowatt standby / 500-kilowatt prime EPA Tier 4 Final / EU Stage 5 mobile trailer diesel generator powered by the Volvo Penta TWD1682GE — a 16.12-liter, six-cylinder turbocharged and charge-air-cooled engine. It is the second-largest model in Blue Star's Tier 4 Final mobile lineup and the first with a significant split between standby and prime ratings (550/500 kWe).
Blue Star Power Systems mounts the TWD1682GE on an aluminum road trailer with a 550-gallon integral fuel tank and 52.8-gallon DEF tank, paired with a Leroy-Somer 572RSL6429 alternator and DSE DCP7310 controller. At 24,750 lbs, the VD550-04FT4MP requires a commercial tractor for transport. The 334.5 × 99.5 × 144 in trailer is the largest platform in the Tier 4 Final mobile VD series before the VD600.
Standby vs Prime at 550 kW#
Unlike most smaller VD mobile models where standby and prime ratings are equal, the VD550-04FT4MP has a 50 kWe spread: 550 kWe standby (rated for emergency use without continuous duty limits) vs 500 kWe prime (rated for continuous variable power service). This is an important distinction for applications where continuous prime power use is anticipated — size the system to the prime rating (500 kWe) for continuous duty applications. Do not use the 550 kWe standby rating to size a continuous prime power application.
The 334.5 × 99.5 Inch Platform#
The VD550-04FT4MP and VD600-04FT4MP share the same 334.5 × 99.5 in trailer footprint and 550-gallon fuel tank. The 52.8-gallon DEF tank represents a major step up from the 18.5 gallons used in all smaller models. At this output level, DEF consumption is substantial — plan DEF logistics the same way fuel logistics are planned.
When to specify the VD550-04FT4MP#
- 500–550 kW three-phase emergency standby mobile power at industrial, municipal, healthcare, or data center sites
- Prime power applications at 500 kWe or below (use the prime rating, not standby, for continuous duty sizing)
- Sites up to 4,921 ft elevation at ambient temperatures to 122°F
- Applications requiring EU Stage 5 dual certification
- Projects where the 334.5 × 99.5 in trailer is acceptable and 550 kWe standby / 500 kWe prime satisfies the load
Our service experience#
The TWD1682GE is a large, complex engine requiring the full Volvo Penta TWD service schedule — oil, coolant, air filtration, fuel injection system, and aftertreatment (T4F/Stage 5) at specified intervals. The 52.8-gallon DEF tank at 38.3 gph diesel consumption means DEF must be treated as a primary consumable on extended deployments. At 24,750 lbs and 334.5 in length, site access logistics require advance planning — confirm road weight limits and site entry dimensions before deployment. Annual full-load testing (38.3 gph) is mandatory for maintaining aftertreatment health. The 72-inch trailer height (144 in total unit height) may require oversize permits in some jurisdictions.



