GM LS Return-Style Fuel System Plumbing Kit with Walbro 255 Pump
WA01021
The GM LS Return-Style Fuel System Plumbing Kit provides the core components needed to build a clean, reliable return-style fuel system for an LS swap, rock crawler, buggy, trail rig, or off-road race vehicle. The package combines a Walbro 255 LPH fuel pump with premium Fragola fittings, a 10-micron post-pump fuel filter, and 30 feet of flexible -6 AN nylon race hose.
The Walbro 255 LPH pump is a proven choice for many naturally aspirated and moderate-performance LS combinations, while the lightweight nylon hose is easier to route through custom chassis and tight engine bays than traditional stainless-braided line. The included quick-connect adapters simplify connection to common GM LS fuel rails, and the return-style layout supports consistent pressure control when paired with a compatible external fuel pressure regulator.
Includes:
- (6) -6 AN Straight Hose-End Fittings
- (3) -6 AN 90-Degree Hose-End Fittings
- (1) 3/8" Quick-Disconnect to -6 AN Straight Adapter
- (1) 5/16" Quick-Disconnect to -6 AN Straight Adapter
- (1) Walbro 255 LPH Fuel Pump with Sleeve and Clamps
- (2) Fuel Pump to -6 AN Fittings
- (1) Fragola 10-Micron Premium Post-Pump Fuel Filter with -6 AN Fittings
- (30 ft) -6 AN Premium Nylon Race Hose
Note: A compatible external return-style fuel pressure regulator is required. Fuel tank fittings, electrical wiring, relay, fuse, pre-filter, and mounting hardware may also be required depending on the application.
Specifications
| Specification | Details |
|---|---|
| Product Type | Return-Style Fuel System Plumbing Kit |
| Engine Application | GM LS Engines |
| Fuel System Configuration | Return Style |
| Fuel Pump | Walbro 255 LPH |
| Fuel Line Size | -6 AN |
| Hose Length | 30 Feet |
| Hose Type | Premium Nylon Race Hose |
| Post-Pump Filter | Fragola 10-Micron Fuel Filter |
| Fitting Brand | Fragola Performance Systems |
| Fuel Rail Adapters | 3/8" and 5/16" Quick-Disconnect to -6 AN |
| Fuel Pressure Regulator Included | No |
Fitment
Common Applications:
- GM LS engine swaps
- Rock crawlers and rock bouncers
- Tube chassis buggies
- Ultra4 and off-road race vehicles
- Trail rigs
- Custom trucks and performance vehicles
- Return-style aftermarket LS fuel rails
- Compatible factory LS fuel rails using 3/8" and 5/16" quick-connect fittings
Fitment Notes:
- Designed for return-style fuel systems using a dedicated feed and return line.
- Not intended for a factory returnless system unless the complete fuel system is properly converted.
- A compatible external fuel pressure regulator is required.
- Verify fuel rail fitting sizes before installation.
- Confirm that the pump, injectors, regulator, hose size, and filter capacity are appropriate for the engine's horsepower and fuel type.
- Fuel pump wiring should use a properly sized relay, fuse, and power supply.
- Route fuel lines away from exhaust heat, sharp edges, driveline components, and suspension movement.
- Secure all hoses at regular intervals using fuel-compatible clamps or line supports.
Tech Insight
What is a return-style LS fuel system?
A return-style system sends fuel from the tank to the engine through a feed line, regulates pressure near the engine or fuel rail, and sends excess fuel back to the tank through a dedicated return line. This layout gives the regulator direct control over rail pressure and is commonly used in custom LS swaps, race vehicles, and off-road builds.
What fuel rails will this kit work with?
The kit is intended for LS fuel systems that use both a supply and return line. The included 3/8" and 5/16" quick-connect adapters support many common GM LS fuel rail connections, while the -6 AN hose and fittings can also be adapted to aftermarket return-style rails. Always confirm the connection sizes on the specific fuel rail before installation.
Is a fuel pressure regulator included?
No regulator is listed in the included components. A compatible external return-style fuel pressure regulator must be selected separately and matched to the injectors, pump, engine management system, and required base fuel pressure.
Is the Walbro 255 LPH pump suitable for an LS swap?
The Walbro 255 LPH pump is widely used in naturally aspirated and moderate-performance LS combinations. Actual horsepower capability depends on fuel pressure, voltage at the pump, injector demand, fuel type, and the complete fuel system. Higher-output or forced-induction engines may require a larger pump or dual-pump system.
What is the purpose of the 10-micron post filter?
The post-pump filter removes fine contaminants before fuel reaches the regulator and injectors. A 10-micron filter is commonly used after an EFI fuel pump to protect injectors with small internal passages.
Why use nylon race hose instead of stainless-braided hose?
Nylon race hose is lightweight, flexible, and easier to route through tight chassis areas. It also reduces abrasion against nearby components compared with exposed stainless braid. Proper hose supports and heat protection are still required.
Can this kit be used with ethanol-blended fuel?
The supplied description identifies the nylon hose as compatible with modern pump gas and ethanol blends. Compatibility of the pump, filter, regulator, seals, and every fitting should still be confirmed for the exact fuel being used, especially with high-ethanol fuels.
Can this kit support a turbocharged or supercharged LS engine?
It may be suitable for some moderate combinations, but forced-induction engines often require greater pump capacity, larger injectors, boost-referenced pressure regulation, and potentially larger fuel lines. Fuel demand should be calculated before selecting the final system.
