Walbro 255 LPH high pressure fuel pump & fitting kit - NSX, 1991-05


The Walbro 255 liter per hour (LPH) high pressure (HP) fuel pump is the most popular in-tank fuel pump upgrade for the NSX. The pump flows 255 LPH of fuel at a base pressure of 43.5 PSI at 13.5 volts (an increase of approximately 65% over the factory pump).

This fuel pump is ideally suited as a direct factory replacement for naturally aspirated NSX all the way to 600 bhp (approximately 530 wheel horsepower) with gasoline forced induction (supercharged/turbocharged) NSX.

This high pressure version included is particularly well suited to applications requiring high fuel rail pressure.

The Walbro 255 LPH HP fuel pump is a universal design - ScienceofSpeed includes a complete NSX specific installation kit allowing direct replacement of the factory fuel pump and step by step installation instructions from ScienceofSpeed.

Under normal operation (60 PSI & 13.2v), this pump can supply 215 LPH or 597 cc/min per injector in the NSX engine, which is enough for approx 580 BHP with gasoline fuel. See fuel pump comparison graph.

This fuel pump for example can supply 240 LPH (or 667 cc/min per injector in the NSX engine) which is enough flow for approximately 595 BHP (gasoline) or 445 BHP (E85) based on fuel rail pressure at 60 PSI, fuel pump voltage at 13.5V, and BSFC at .60 (gasoline) or .78 (E85), and injectors at 80% duty cycle. This example is approximate, and should be verified based on the application's specific conditions. This fuel pump is not recommended for use with ethanol/E85.

For applications requiring more than 10 amps of current (see chart below) to supply the required fuel flow (which exceeds the recommended factory wiring capacity), ScienceofSpeed offers a complete fuel pump power distribution kit. Generally, this pump does not require upgrading of fuel pump wiring (it is used with higher capacity fuel pumps).

Walbro 255 LPH high pressure fuel pump & fitting kit - NSX, 1991-05