Walbro GSL392 255 LPH Inline Fuel Pump
GSL392
The Walbro GSL392 255 LPH Inline Fuel Pump is a high-pressure external fuel pump designed for EFI fuel systems in LS swaps, off-road vehicles, race cars, and custom performance builds. Its 255 LPH flow capacity and inline configuration make it a practical option for fuel cells and custom fuel systems where an external pump is preferred over an in-tank setup.
The GSL392 works well in custom builds because it provides proven EFI fuel delivery in a compact, serviceable package that is easy to incorporate into custom fuel-system plumbing. Proper pump placement, filtration, fuel-line sizing, pressure regulation, and electrical supply are critical to getting consistent fuel flow and reliable performance from the system.
Installation Components: Walbro Inline Fuel Pump Installation Kit sold separately.
Specifications
| Specification | Details |
|---|---|
| Manufacturer | Walbro |
| Part Number | GSL392 |
| Product Type | High-Pressure EFI Fuel Pump |
| Pump Configuration | External / Inline |
| Rated Flow | 255 LPH |
| Operating Voltage | 12V |
| Fuel System Type | Electronic Fuel Injection |
| Installation | Universal Inline |
| Installation Kit | Sold Separately |
Fitment
Common Applications:
- LS engine swaps
- EFI engine conversions
- Rock crawlers
- Rock bouncers
- Ultra4 and race vehicles
- Custom tube chassis vehicles
- Fuel cell installations
- Street and performance builds
Fuel System Considerations:
- Fuel pump capacity must be matched to engine horsepower, fuel type, operating pressure, and injector requirements.
- Mount the pump low and as close to the fuel tank or fuel cell as practical.
- Provide an unrestricted fuel supply to the inlet side of the pump.
- Use proper pre-pump and post-pump filtration for the complete fuel system.
- Use appropriately sized fuel line for the engine's required fuel volume.
- -6 AN fuel line is commonly used in LS swap and similar EFI applications, but required line size depends on the complete fuel system.
- Use properly sized wiring, relays, and grounds to maintain adequate voltage at the pump.
- Keep the pump and fuel lines protected from exhaust heat, sharp edges, suspension components, and trail debris.
- Verify regulator, injector, fuel rail, and return-line requirements before final installation.
FAQ
Is the Walbro GSL392 a good fuel pump for an LS swap?
Yes. The GSL392 is a popular option for LS swaps that need an external high-pressure EFI pump. Its inline configuration works especially well with fuel cells and custom fuel systems where the builder does not want to package an in-tank pump.
How much horsepower can a Walbro 255 LPH pump support?
There is not one horsepower rating that applies to every installation. Available fuel flow changes with operating pressure and voltage, while the engine's required fuel volume changes with fuel type, injector size, brake-specific fuel consumption, and whether the engine is naturally aspirated or boosted. Size the pump around the complete fuel-system requirements rather than horsepower alone.
Can the GSL392 be used with a fuel cell?
Yes. External inline pumps are commonly used with fuel cells in rock crawlers, buggies, race vehicles, and custom chassis builds. The pump should have a reliable gravity-fed or otherwise unrestricted supply and should be mounted low and close to the fuel cell whenever possible.
Does the Walbro GSL392 replace an in-tank fuel pump?
It can be used as the primary EFI pump in a properly designed external fuel system. Unlike an in-tank pump, the GSL392 mounts outside the tank or fuel cell and is plumbed directly into the fuel line.
Do I need a fuel pressure regulator?
The fuel system must have a method of controlling fuel pressure appropriate for the EFI system. Depending on the build, this may be a separate adjustable regulator or a filter/regulator assembly. Match the regulator and plumbing layout to the engine, injectors, fuel rail, and required operating pressure.
What fuel line size should I use?
-6 AN is commonly used for many LS swaps and moderate-power EFI systems using a 255 LPH pump. Higher fuel demand, long plumbing runs, alternative fuels, or other system requirements may require larger line. Fuel line size should be determined from the requirements of the complete system.
Where should an inline fuel pump be mounted?
Mount the pump low and close to the fuel tank or fuel cell with a free-flowing supply to the inlet. High-pressure EFI pumps are much better at pushing fuel toward the engine than pulling fuel through a long or restrictive inlet line.
What filters should I use with the GSL392?
The pump should be protected by appropriate fuel filtration on both sides of the system. The exact micron rating should be selected around the pump manufacturer's requirements, fuel type, injectors, and complete fuel-system design rather than treating one filter specification as universal.
Can I use the GSL392 on a boosted engine?
Potentially, but the pump must have enough flow at the actual operating fuel pressure to meet the engine's fuel demand. Boost-referenced systems increase fuel pressure as boost rises, which can reduce available pump flow. Higher-horsepower boosted combinations may require a larger pump or multiple-pump system.
