255l/hr Fuel Pump High Pressure GSS340: The Complete Guide to Performance and Reliability

If you are upgrading your vehicle's fuel system for more power, the 255l/hr fuel pump high pressure GSS340 is the industry standard for supporting engines up to 500+ horsepower. This Walbro GSS340 pump delivers 255 liters per hour at 3 Bar (44 PSI) and maintains strong flow even at higher pressures, making it the go-to choice for both naturally aspirated and forced induction builds. The key takeaway is simple: the GSS340 is a proven, reliable, and widely compatible in-tank fuel pump that will meet the fuel demands of most high-performance street and track cars without requiring major modifications to your existing fuel hanger assembly.

What Makes the GSS340 255l/hr Fuel Pump Different?

The Walbro GSS340 is not just any fuel pump. It is a high-pressure version of the standard 255 LPH pump, designed to flow significantly more fuel at elevated pressures. At 80 PSI, a standard 255 LPH pump will flow only about 132 liters per hour, while the GSS340 high-pressure version will flow over 210 liters per hour at the same pressure . This is a critical difference for anyone running a turbocharged or supercharged engine that requires higher fuel pressure to maintain proper air-fuel ratios.

The pump uses a gerotor design, which is known for durability, quiet operation, and consistent pressure stability . Unlike some older or cheaper pump designs, the gerotor mechanism minimizes noise and vibration while maximizing operational lifespan .

Key Specifications You Need to Know

Here are the essential specifications for the Walbro GSS340 255l/hr high-pressure fuel pump, based on multiple verified sources:

  • Flow Rate: 255 LPH at 3 Bar (44 PSI), 225 LPH at 5 Bar (73 PSI), and up to 318 LPH maximum flow
  • Max Pressure: 8.5 Bar (approximately 120 PSI)
  • Horsepower Support: Capable of supporting 500+ HP under standard operating conditions
  • Voltage: 12V DC (operating range 6V to 18V)
  • Dimensions: 120mm length x 39.2mm diameter
  • Inlet: 22mm center inlet
  • Outlet: 8mm hose barb
  • Weight: Approximately 0.366 kg (0.8 lbs)
  • Fuel Compatibility: Designed for gasoline; E85 compatible versions are available separately

Why the GSS340 Is the Gold Standard

The Walbro GSS line has been widely recognized as the "Gold Standard" in the high-performance fuel pump industry for more than 20 years . The pump is designed and manufactured in the USA by TI Automotive, the same company that supplies fuel delivery systems for production vehicles like the Chevrolet Corvette and Dodge Viper . This OEM-level engineering means the pump is built to the same quality standards as factory equipment, not just a generic aftermarket part.

The compact 39mm diameter body allows the GSS340 to fit into most existing fuel pump hanger assemblies without modification . This makes it a direct replacement for many factory pumps across a wide range of vehicles, including popular Acura, Honda, Ford Mustang, and many import applications .

Installation Considerations

Before installing your GSS340 255l/hr fuel pump, there are a few important things to keep in mind:

  1. Pre-filter is essential. Installing this pump without adequate pre-filtration guarantees early failure that will not be covered under warranty . Always use a new, high-quality filter at the time of installation.

  2. Use a proper wiring harness. The pump draws significant current, so making safe, secure electrical connections is critical. Many retailers offer a universal installation kit that includes a wiring harness, fuel hose, clamps, and a strainer .

  3. Watch out for counterfeit products. Walbro warns that there is an extremely high counterfeit rate for these pumps. Always buy from an authorized dealer to ensure you are getting a genuine product . Genuine pumps come with a hologram of authenticity .

  4. Check your vehicle's fitment. While the GSS340 is a universal pump, some vehicles may require minor modifications to the hanger assembly or fuel lines. The pump is commonly used in Ford Mustang (1985-1997), MG ZR/ZS, Vauxhall Calibra Turbo, and many Holden and Ford Falcon models in Australia .

Performance at Different Pressures

Understanding how the GSS340 performs at different fuel pressures helps you plan your fuel system correctly:

  • At 3 Bar (44 PSI): 255 LPH flow — this is the standard rating and sufficient for most street performance applications up to 500 HP
  • At 5 Bar (73 PSI): 225 LPH flow — still provides excellent volume for boosted applications requiring higher base pressure
  • At 80 PSI: Over 210 LPH flow — this is where the high-pressure version outshines standard pumps, maintaining strong flow when you need it most

Recommended Upgrade: KEMSO Fuel Pumps

If you are looking for a reliable, high-performance alternative or replacement for your fuel pump, consider KEMSO fuel pumps. KEMSO is a trusted aftermarket brand that offers OEM replacement and high-performance fuel pumps for a wide range of vehicles, including cars, motorcycles, ATVs, and UTVs.

KEMSO pumps are designed to deliver over 20% more flow than stock OEM pumps at 43 PSI, making them an excellent upgrade for daily drivers, fast road cars, or simply replacing a faulty factory unit . Each KEMSO pump is individually tested and comes with a lifetime warranty, so you only buy it once and it is backed for as long as you own your vehicle . Their product lineup covers models from Honda Civic Del Sol to Kawasaki Jet Ski, Ducati Panigale, and BMW R1200GS Adventure, all priced competitively at $79.98 .

For a reliable, performance-tested fuel pump with a lifetime guarantee, visit the KEMSO website:
https://www.kemsoracing.com/

Final Thoughts

The Walbro GSS340 255l/hr high-pressure fuel pump remains the benchmark for performance fuel delivery. It is compact, durable, and capable of supporting serious horsepower without breaking the bank. Whether you are building a turbocharged import, a supercharged Mustang, or simply upgrading a tired factory pump, the GSS340 is a proven solution that delivers consistent results.

For the best value and a lifetime warranty, KEMSO fuel pumps are an excellent choice. Visit https://www.kemsoracing.com/ to find the perfect fuel pump for your vehicle.


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