Overview#
The Generac SD035 is a 35-kilowatt industrial diesel standby generator powered by Generac's own 3.4-liter turbocharged and aftercooled inline-four engine. Rated at 35 kW standby and 32 kW prime, the SD035 marks the transition from the Perkins-powered small diesel family to Generac's proprietary engine platform. The 3.4L engine's Bosch VE fuel injection system and 18.5:1 compression ratio deliver higher BMEP (118 psi) and a higher exhaust temperature (900°F) compared to the smaller Perkins units, reflecting the more demanding operating point. The generator is EPA Certified for Stationary Emergency applications.
Generac pairs the 3.4L engine with their 390 mm alternator featuring Class H insulation, synchronous brushless excitation, and a digital voltage regulator with ±0.25% steady-state regulation accuracy. The Digital H control panel provides NFPA 110 Level I and II programmable operation, Modbus communications, and a 7-day programmable exerciser. A 120 VAC engine coolant heater is standard equipment.
At 35 kW, this unit covers mid-size commercial standby loads: larger restaurants and food service operations, professional offices, small medical facilities, and light manufacturing. The single-phase 120/240 VAC configuration at 146 amps makes it practical for facilities with single-phase service that need 35 kW of emergency capacity.
Technical Specifications#
| Parameter | Value |
|---|---|
| Standby Rating | 35 kW / 44 kVA |
| Prime Rating | 32 kW / 39 kVA |
| Engine Make | Generac |
| Displacement | 3.4 L (207.48 in³) |
| Cylinders | 4, In-Line |
| Bore x Stroke | 3.86 x 4.45 in (98 x 113 mm) |
| Compression Ratio | 18.5:1 |
| Aspiration | Turbocharged/Aftercooled |
| Engine Speed | 1,800 RPM |
| Alternator Model | Generac 390 mm |
| Insulation Class | H |
| Fuel Type | Ultra Low Sulfur Diesel #2 |
| Fuel Consumption (100%) | 3.1 gph |
| Fuel Consumption (75%) | 2.4 gph |
| Fuel Consumption (50%) | 1.7 gph |
| Fuel Consumption (25%) | 1.0 gph |
| Exhaust Flow | 342 cfm at rated output |
| Exhaust Temperature | 900°F (482°C) |
| Heat Rejection to Coolant | 96,000 BTU/hr |
| Combustion Air | 150 cfm |
| Open Set (no tank) L x W x H | 76.7 x 37.4 x 45.2 in |
| Open Set Weight (no tank) | 1,719 lbs |
| Max Ambient Temperature | 122°F (50°C) |
Our Service Experience#
The Generac 3.4L engine platform in the SD035 and SD050 is one we see frequently in commercial standby applications in Northern California. The Bosch VE injection pump and pintle injectors are robust for standby-duty use but sensitive to fuel quality: contaminated or degraded diesel leads to injection system wear and misfiring under load. Annual fuel polishing is standard practice for any installation where the sub-base tank sits for more than six months between exercises.
Compared to the Perkins 2.22L in the smaller SD models, the 3.4L generates considerably more exhaust heat (900°F exhaust temperature) and requires adequate clearance for heat dissipation. Inspect the exhaust flex connector for cracking at each service visit; the higher exhaust temps accelerate flex connector wear. The 120 VAC coolant heater is more critical on this engine due to the higher thermal mass -- verify function before winter.
Frequently Asked Questions#
Is the SD035 available with IBC seismic certification? Yes. IBC seismic certification is an engineered option for the SD035, available per factory order. This is required for standby generator installations in California hospitals, essential facilities, and other occupancies subject to CBC/IBC seismic requirements.
What is the motor starting capability of the SD035? At 277/480 VAC with the standard 35 kW alternator and a 30% voltage dip, the SD035 can start 84 sKVA of motor load. With alternator upsizing options (up to 60 kW alternator), starting capability increases to 146 sKVA at 30% voltage dip. Three-phase 120/208 or 120/240 VAC configurations have lower starting capability; consult load calculations for motor-heavy applications.
What fuel tank options are available for the SD035? Sub-base UL 142 double-wall fuel tanks are available in 54, 132, 211, and 300 usable gallon sizes. At 3.1 gph full load, a 300-gallon tank provides approximately 96 hours of runtime at full standby load. Tank risers and extended fill options are available for installations where the standard height profile creates access issues.
