Description
ZF BW-121 4.04 Gearbox
The ZF BW-121 with a 4.04:1 gear ratio is a heavy-duty marine transmission designed to handle up to 230 kW of power at a rated 1800 RPM. It weighs roughly 280 to 400 kg and includes integrated oil filtration, cooling control, and SAE housing compatibility.
Technical Specifications
- Manufacturer: ZF Friedrichshafen AG (Marine Division)
- Model: BW-121
- Gear Ratio: 4.04:1 (often listed around 4.00:1 to 4.04:1)
- Input Power Capacity: 230 kW (approx. 308 hp) at 1800 RPM
- Specific Rating: ~0.128 kW/RPM
- Approximate Dry Weight: 280 kg – 400 kg (depending on configuration and accessories)
- Housing Type: SAE 1
Key Features & Design
- Cooling & Filtration: Built-in connections for external oil coolers and integrated oil filter control.
- Engagement: Heavy-duty mechanical or hydraulic clutch/coupling control designed for commercial and continuous marine applications.
- Applications: Frequently paired with medium-speed marine diesel engines (such as older Volvo Penta or Cummins setups) in displacement hulls, workboats, and small coastal vessels
Core Performance Specifications
- Rated Power Capacity: 230 kW (approximately 308 horsepower).
- Nominal Engine Speed: 1800 RPM.
- Power-to-Speed Ratio: 0.128 kW/RPM, signifying heavy continuous output and torque capabilities.
- Exact Reduction Ratio: 4.04:1 (frequently rounded to 4:1 in fleet logs)
