MQ Power · WhisperWatt Super-Silent

MQ Power DCA-400 WhisperWatt

336 kW standby / 320 kW prime · Diesel · Liquid-cooled

400 kVA (320 kW prime) portable diesel generator. The largest WhisperWatt Super-Silent for major construction, infrastructure, and large-scale emergency power.

MQ Power MQ Power DCA-400 WhisperWatt generator — specifications and details
Standby power
336 kW / 320 kW prime
Voltage options
120/240V, 208V, 240V, 277/480V, 480V
Frequency / Phase
60 Hz · 1/3-phase
Engine
Isuzu BG-6WG1X
EPA / Emissions
Tier 4 Final
construction-majorrental-fleetevents-largeemergency-commercialdisaster-recoverydata-center-tempinfrastructure
Configure & QuoteDownload spec sheet

Overview#

The MQ Power DCA-400 WhisperWatt is a 400 kVA (320 kW prime / 336 kW standby) portable diesel generator powered by an Isuzu BG-6WG1X 6-cylinder. It is the top of the WhisperWatt Super-Silent towable lineup — above the DCA-300 and suited for applications requiring sustained 250-320 kW at a portable location with meaningful sound attenuation.

Two things set the DCA-400 apart from the DCA-300: CARB compliance (California job sites) and the Isuzu platform (broader rental fleet familiarity in North America versus the JD-powered DCA-300).

CARB compliance#

The DCA-400 is one of the few portable generators in this power range that is certified by the California Air Resources Board:

  • Deployable on California construction sites where EPA-only generators cannot operate
  • Meets stringent NOx and PM standards beyond EPA Tier 4 Final
  • Rental advantage — a single CARB-compliant unit serves all US markets

Tier 4 Final aftertreatment at 320 kW#

At this capacity, the aftertreatment system is substantial and adds meaningful operational requirements:

  • DPF — requires periodic regeneration; automatic but operator awareness essential
  • SCR (DEF) — large DEF consumption at 320 kW sustained; plan DEF logistics alongside fuel
  • DPF ash cleaning — eventual service requirement per OEM schedule
  • Regen management — never interrupt an active regen cycle; extended regen interruption causes forced shutdown

Skid vs trailer configurations#

The DCA-400 is available in both configurations:

  • Skid: 181"×59"×100", 13,184 lbs — for semi-permanent placement or crane-set deployments
  • Trailer (TRLR400XF3DAE): 265"×94"×110", 17,194 lbs — for over-the-road towing

Our service experience#

We deploy DCA-400 units for the largest temporary power requirements in our market — major construction projects, extended utility outages affecting commercial facilities, and large public events requiring a single large portable rather than paralleled smaller units. At this size, the technical sophistication of the Tier 4 Final aftertreatment system means pre-delivery briefings and planned service intervals are more important than with smaller units. We recommend establishing a DEF delivery cadence as part of the deployment plan, not as an afterthought.

Engineering specifications

Physical

Length
181 in
Width
59 in
Height
100 in
Dry weight
13,184 lb

Acoustic

Sound @ 7m, full load
69 dBA
Enclosure
Sound-attenuated

Fuel system & runtime

Integral fuel tank
405 gal
Fuel use @ full load
22.5 GPH
Fuel use @ 75% load
17.3 GPH
Fuel use @ 50% load
12.2 GPH

Documents & downloads

Spec sheets & manuals

Ready to order this model?

Configure your MQ Power DCA-400 WhisperWatt

Lock the enclosure, fuel system, transfer switch, and add-ons — we'll confirm pricing, availability, and lead time within one business day. Prefer a free-form quote? That option is still here.

Configure & Quote →Just request a quoteDownload datasheet

Estimate runtime for the MQ Power DCA-400 WhisperWatt

Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.

Estimate runtime on this tank

Estimated runtime

23.3 hours(1.0 days)

Fuel consumption ≈ 17.36 GPH at 75% load. Estimate based on industry-typical 1800 RPM standby curves (≈0.07 GPH/kW at full load). Actual consumption varies by engine, ambient temperature, fuel quality, and tuning.

Service intervals

Manufacturer-recommended intervals for the MQ Power DCA-400 WhisperWatt under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter
Every 500 hours or 12 months
Air filter
Every 1000 hours
Fuel filter
Every 500 hours
Major overhaul
≈ 20,000 hours

Common failure modes

What we've seen fail on this platform. Use as a service-planning reference, not a diagnostic — actual failure modes depend heavily on duty cycle and maintenance history.

ComponentSymptomTypical hoursSeverity
DEF system (SCR)DEF fault codes, derate warning, progressive power derate3,000+moderate
DPF (Diesel Particulate Filter)Regen warning, back-pressure fault, power derate4,380+moderate
TurbochargerReduced power, excessive smoke, turbo whine15,000+moderate
Fuel qualityInjector fouling, filter clogging at sustained high load1,000+minor

Frequently Asked Questions

What engine is in the DCA-400?
An Isuzu BG-6WG1X — a 6-cylinder turbocharged diesel rated at 512 HP for generator drive. EPA Tier 4 Final certified and CARB compliant, with DPF and SCR aftertreatment requiring DEF.
Is the DCA-400 CARB compliant?
Yes. The DCA400SSI4F carries California Air Resources Board (CARB) compliance, making it usable on California job sites where standard EPA Tier 4 Final units cannot operate. This is a significant differentiator for rental fleets serving California.
How does the DCA-400 compare to the DCA-300?
The DCA-400 (320 kW prime) adds 33% more output over the DCA-300 (240 kW prime) using an Isuzu 6-cylinder rather than John Deere. The DCA-400 also carries CARB certification. At 69 dBA vs 72 dBA, the DCA-400 is actually quieter per the WhisperWatt enclosure spec.
What's the DCA-400 used for?
Major construction (high-rise, data centers, hospital construction), large-scale temporary power for events requiring 250-320 kW sustained, disaster recovery, and emergency backup for commercial facilities with large critical loads.

Compatible equipment

Transfer switches

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