Generac · SD Series (Industrial Diesel)

Generac SD150-4

150 kW standby / 135 kW prime · Diesel · Liquid-cooled

150 kW industrial diesel standby generator with EPA Tier 4 Final emissions certification. Iveco/FPT 6.7L turbocharged-aftercooled inline-6 with electronic injection and exhaust aftertreatment, Digital H control with NFPA 110 Level I/II.

Generac Generac SD150-4 generator — specifications and details
Standby power
150 kW / 135 kW prime
Voltage options
120/208V, 120/240V, 277/480V, 346/600V
Frequency / Phase
60 Hz · 3-phase
Engine
Iveco/FPT 6.7L · 6.7L
Alternator
Generac K0150124Y21
Commerciallight-industrialHealthcareGovernmentData Centers
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Overview#

The Generac SD150-4 is the EPA Tier 4 Final certified variant of the SD150, a 150-kilowatt industrial diesel standby generator powered by an Iveco/FPT 6.7-liter turbocharged and aftercooled inline-six engine with electronic fuel injection. Rated at 150 kW standby and 135 kW prime (188/169 kVA), the SD150-4 adds exhaust aftertreatment technology to meet Tier 4 Final emissions standards, which require significantly lower particulate matter and nitrogen oxide emissions compared to Tier 3 or emergency-only certified units.

The "-4" designation in the model name indicates Tier 4 Final (T4F) compliance. The underlying engine platform -- including the 4-valve cylinder head and electronic injection that distinguish the SD150 from the SD130 -- carries over to the T4F variant. The SD150-4 adds a diesel particulate filter (DPF) and diesel oxidation catalyst (DOC) in the exhaust system. This makes the SD150-4 suitable for installations in air quality non-attainment zones or projects where local permitting authorities require Tier 4 Final emissions certification.

Generac offers the SD150-4 with enclosure options from open skid through Level 2 sound-attenuated in steel or aluminum with RhinoCoat powder-coated finish. The Digital H control panel provides NFPA 110 Level I and II programmable operation, Modbus communications, and IBP/OSHPD seismic certification availability.

Our Service Experience#

The SD150-4's aftertreatment system adds a layer of maintenance complexity over the standard SD150. The diesel particulate filter requires periodic regeneration, and standby generators that exercise infrequently may not reach sufficient exhaust temperatures for passive regeneration. We recommend scheduled loaded exercise cycles of at least 30 minutes at a minimum of 50% load to maintain proper DPF function. Annual DPF inspection and cleaning should be added to the standard service schedule.

The electronic fuel injection system inherited from the SD150 platform is sensitive to fuel quality. Ultra-low sulfur diesel (ULSD) is mandatory for Tier 4 Final compliance, and any fuel contamination or degradation accelerates both injector and aftertreatment component wear. Annual fuel polishing and biocide treatment are recommended for standby installations with infrequent loaded operation.

Engineering specifications

Physical

Length
117 in
Width
50 in
Height
57 in
Dry weight
3,980 lb

Fuel system & runtime

Fuel use @ full load
11.2 GPH
Fuel use @ 75% load
8.8 GPH
Fuel use @ 50% load
6.2 GPH

Thermal & ventilation

Heat to coolant
412,900 BTU/hr
Exhaust flow
1,559 CFM
Exhaust temp
895 °F
Combustion air
7,946 CFM

Documents & downloads

Spec sheets & manuals

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Estimate runtime for the Generac SD150-4

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

23.1 hours(1.0 days)

Fuel consumption ≈ 8.64 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 Generac SD150-4 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
Load bank test
Every 12 months

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
Fuel quality / degradationHard starting, injector fouling, reduced power output4,380+moderate
TurbochargerPower loss, excessive smoke under load, oil consumption15,000+moderate
Exhaust aftertreatment (DPF/DOC)Regeneration fault codes, increased backpressure, derate warning10,000+moderate
Electronic fuel injectorsMisfiring, rough running, fault codes, hard start20,000+moderate
BatteryFailed to start, slow cranking8,760+minor

Frequently Asked Questions

What is the difference between the SD150-4 and the standard SD150?
The SD150-4 is the EPA Tier 4 Final certified variant of the SD150. Both use the Iveco/FPT 6.7L inline-6 engine with electronic injection at 150 kW standby / 135 kW prime, but the SD150-4 adds exhaust aftertreatment (diesel particulate filter and diesel oxidation catalyst) to meet Tier 4 Final emissions standards. The standard SD150 is EPA Certified for Stationary Emergency applications only, while the SD150-4 meets stricter Tier 4 Final requirements for installations where air quality regulations demand lower particulate and NOx emissions.
What is the fuel consumption of the Generac SD150-4?
The SD150-4 shares the same 6.7L engine platform as the standard SD150. Fuel consumption at standby rating is approximately 11.2 gallons per hour at full load (100%), 8.8 gph at 75% load, and 6.2 gph at 50% load. Actual consumption may vary slightly due to the aftertreatment system's periodic regeneration cycles.
What voltages are available?
The SD150-4 is available in three-phase configurations: 120/208 VAC, 120/240 VAC, 277/480 VAC, and 346/600 VAC, all at 0.8 power factor.

Compatible equipment

Transfer switches

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