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255L/hr High Pressure Fuel Pump

Walbro's high output in-tank fuel pump increases fuel delivery to meet the demands of highly tuned engines. It maintains high outputs at increased pressures making it ideal for turbocharged applications. It is a direct fit (in some cases requiring an installation kit) in a wide range of applications. The GSS342 has inline inlet and outlet fittings.

Usually ships within 2 to 3 days

Manufacturer: Walbro


  • Subaru MY99-07 (Excluding Legacy MY05-07)
  • Mitsubishi EVO 8-9
  • Mitsubishi Eclipse/Talon/Laser MY95-99
  • Acura Integra MY94-01, RSX MY02-06
  • Ford Mustang Cobra
  • Honda Civic MY92-00, S2000 MY00-07, Accord MY94-97
  • Mazda Miata MY94-97, MX6 MY94-97
  • Nissan 200SX MY95-98, Sentra MY98-99
  • Toyota Supra MY93-98

When is a high pressure pump required? A forced induction application running any significant boost levels should use a high pressure pump. Fuel pressure for most applications is referenced to manifold pressure at a 1:1 rate. For example, at 20psi of boost the fuel pressure will be 20psi above the base fuel pressure. It is imperative that the fuel pump output is sufficient to meet the demands of the engine at the expected maximum pressure. If the pump flow is insufficient air fuel ratios could potentially lean out under the most critical conditions. At 60psi fuel pressure the GSS-342 fuel pump will flow approximately 220L/hr. At 70psi that flow drops below 200L/hr.

How do I determine how much fuel pump flow is required? Its fairly simple. The injector flow per hour multiplied by the number of injectors will tell you the maximum required flow. For example, a 4 cylinder engine with 1000cc injectors has a maximum flow potential of 240L/hr (1000cc/min x 1L/1000cc x 60min/hr x 4 = 240L/hr). If the fuel pump output at the peak fuel pressure and taking into account any voltage drop in the electrical supply to the pump is higher than 240 L/hr then it should be sufficient. Obviously a margin of safety should be employed. However, injectors should never be run at 100% duty cycle so by this method there will be some small margin of safety already built in to the calculations.

What do I need to know about the electrical wiring of the fuel pump? It is very important to minimize voltage drops in the electrical system. If the wiring to the pump is too small to support the amperage requirements the voltage at the pump will be reduced and the fuel flow will drop off. At 40psi pump output will be more than 15% lower running at 12V compared to 13.5V.