GFB FX-S Instruction Manual

GFB FX-S

Fuel Pressure Regulator

Instruction Manual

Part # 8050

HEAD OFFICE/AUSTRALIA

Go Fast Bits

www.gfb.com.au

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Ph: [phone]

What’s included:

» FX-S Fuel Pressure Regulator

» 1/16” NPT 4mm hose barb

» Mounting bracket

» 3x 1/8” NPT blanking plugs

» 2x M4 x 12 button head

bracket screws

Thank you for purchasing your new GFB FX-S Fuel Pressure Regulator. Our Engineers at GFB have spent countless
hours in development to ensure you have purchased the highest quality product available.

The FX-S is street and race fuel safe, suitable for regular unleaded, methanol, ethanol or diesel fuels.

The FX-S has ve fuel ports on the body (4 inlet/reference pressure, 1
outlet), all of which are 1/8” NPT. Please ONLY use 1/8” NPT ttings, and
note that whilst 1/8” BSP ttings look very similar and will seem to screw
in, they will not provide a leak-proof joint.

Fuel-safe thread tape or sealant will be required on all tting threads.

You can use any of the 4 side ports on the FX-S for fuel inlet, gauge, or
EFI fuel pressure sensor, depending on what conguration best suits your
needs. Any un-used ports are to be pugged with the supplied NPT plugs.

The outlet on the underside of the FX-S is ONLY for fuel return to the tank

- do not use this port for anything else.

Warning!!! – Fuel systems operate under considerable
pressure both during operation and when powered
down. Extreme caution must be taken when working with
fuels as they are extremely ammable and dangerous.

Modications to fuel systems must be undertaken by a
qualied mechanic or technician, using appropriate safe­ty measures (i.e. safety gloves, re extinguisher, etc.) or
serious injury may occur.

1/8” NPT

FUEL INLET/GAUGE PORT (x4)

Use thread sealant/tape

1/16” NPT

VACUUM PORT (x1)

Use thread tape/sealant

1/8” NPT

OUTLET PORT (x1)

Use thread sealant/tape

**note: if a fuel pressure sensor is to be used on
the rear gauge port, a 1/8” NPT male to 1/8” NPT
female right angled adaptor will be required.

Introduction

There are many dierent congurations for connecting the FX-S, some of the more common are shown below. The best
setup for your car will depend on your engine (single or twin rail), the amount of space you have, whether you are using
factory hoses or completely re-designing the fuel system.

Fuel Rail

From fuel pump

To fuel tank

Single Rail:

This is the most common setup for a single fuel rail
engine.

From fuel pump

To fuel tank

Fuel Rail

Fuel Rail

Series Rail:

This is the most common basic setup for a twin-rail
vee and at engine. Because fuel ows through
one rail then the other, it is known as a “series”
setup. Usually factory twin-rail engines will use a
series setup.

From fuel pump

To fuel tank

Fuel Rail

Fuel Rail

Parallel Rail:

It is often considered an improvement to change
factory series rail setups to parallel so fuel is dis­tributed evenly to both rails. However, if properly
designed, both systems should work equally well.

Fuel Rail

Fuel Rail (twin rail setup)

From fuel pump

To fuel tank

Semi-Returnless or “Dead Head”:

This conguration is sometimes used to help
reduce fuel temperature by not owing it
through the rail/s. Instead, fuel circulates only
through the pressure regulator, and ows to
the rail/s when the injectors re.

Fuel Line Configurations

Step 1:

Remove fuel pump relay or fuse to run the engine until it stalls. This will relieve the majority of the fuel pressure from the
existing system.

Step 2:

Let engine cool down. This will minimize any chance of fuel vapour igniting due to hot exhaust etc.

Step 3:

Disconnect battery terminals to prevent potential ignition of fuel in the event of an accidental short circuit.

Step 4:

Remove factory fuel pressure regulator. Covering the fuel hose with a cloth will help stop any spraying of fuel when dis­connecting the hose from the fuel line. Clean up any residual fuel that may have leaked out.

Step 5:

Fit new fuel lines and ttings on vehicle side. Do not cut corners here and use cheap or incorrectly-sized ttings, as this
will almost always be the most expensive option if you end up with a fuel leak, causing a re and potentially harming you
and burning your beloved project!

Step 6:

Determine the best mounting location for the FX-S, and install using the supplied bracket. You will need to use either
M6, or ¼” threaded fasteners to mount the FX-S, usually on the strut tower, rewall, directly to the fuel rail, or onto the
intake manifold. Modication to the bracket may be required to suit your mounting application. The FX-S is secured to
the bracket using the supplied M4x12 button head screws (please use a METRIC 2mm hex key).

Step 7:

Connect the fuel hoses and ttings, making sure everything is tightened and any braided hoses are correctly tted. Again,
we do not want any fuel leaks whatsoever. ENSURE YOU HAVE THE FUEL SUPPLY AND DRAIN HOSES CONNECTED TO THE
CORRECT CORRESPONDING PORTS ON THE FX-S. Since the inlet and outlet ports are the same size, it is possible to ac­cidentally swap them. If this happens the FX-S will not function correctly and may result in damage to the engine or fuel
pump.

Step 8:

Re-connect the battery and fuel pump fuse, then prime the fuel pump to check for any leaks. It is perfectly normal to
hear a “squeaking” noise when you prime the fuel pump for the rst time. This noise will only be heard until all the air is
purged out of the fuel lines.

Step 9:

With no vacuum hose connected to the top of the FX-S, start your engine, and use a 3mm hex key to adjust the base fuel
pressure by turning the adjustment screw. Looking from the top of the FX-S, turning the Hex key clockwise will increase
fuel pressure, and anti-clockwise will reduce fuel pressure. If you are unsure where to set your base fuel pressure, a good
starting point is approximately 45psi (3bar). When you are satised with your set pressure, tighten the 10mm jam nut
against the FX-S to prevent vibration from loosening the adjustment screw and resetting your fuel pressure. Now you can
switch the engine o again.

Step 10:

Connect a vacuum/boost hose (not included, recommended I.D. 4mm/5/32”) from your intake manifold directly to the
hose barb on the upper half of the FX-S. Please make sure that this hose does not branch o to any other device (i.e. blow
o valve, boost controller, etc) for the fastest and most accurate manifold reference.

Step 11:

Check all hoses and ttings again for any possible fuel leaks. If all checks out OK, you are now ready to run. Please note
that tuning may be required to obtain the correct air/fuel ratios across the RPM range.

HEAD OFFICE/AUSTRALIA

Go Fast Bits

www.gfb.com.au

[e-mail]

Ph: [phone]

Installation