Fuelab 51504 User Manual

Model Number 51504

Fuel P ressure Regul ator

Operating and Installation Instructions

CCAAUUTTIIOONN!!

This product is to be installed only by persons knowledgeable in the repair and modification of vehicle fuel systems

and general vehicle systems modification. Only a qualified technician or mechanic who is aware of applicable

safety procedures should perform the installation of this product.

GASOLINE AND OTHER FUELS ARE FLAMMABLE AND CAN BE EXPLOSIVE!

Perform the installation in a well ventilated location only to minimize the build up of fuel vapors. NO open flames,

smoking or other sources of ignition are to be present during installation, to prevent fire or explosion that can cause

serious injury or death. Grinding, cutting, and drilling must be performed with care to prevent ignition. Draining and

removal of all fuel and ventilation of vapors in vehicle and fuel system is recommended when performing such

procedures. Prop er e ye an d per so n al pr ote c t ion is req uir ed at al l times during install ati on .

WWAARRNNIINNGG!!

The Vehicle’s fuel system may be under pressure! Do not loosen any fuel connections until relieving all fuel system

pressure. Consult an applicable service manual for instructions to relieve fuel system pressure safely.

This product is intended for racing, off-road, or marine use only. This fuel system component is capable of altering

engine tuning and therefore not legal for sale or use on emission controlled motor vehicles.

Product Contents:

Check the diagram and list of components

Check the diagram and list of components (right) to ensure that no components are

(right) to ensure that no components are missing from box. Contact your Fuelab

missing from box. Contact your Fuelab distributor immediately for replacement.

distributor immediately for replacement.

51504 Features and Performance Ratings:

Inlet Port Sizes -6AN Military Port

Seat Size Large

Regulation Slope 0.75 PSI/GPM

Maximum Flow

Capacity

Capacity Pressure

Pressure

Adjustment Range

WARNING! Exceeding maximum flow capacity may result in an over-pressure operating condition .

Before Installation, Plan Entire Fuel System:

These instructions are limited to general topics of regulator component installation and may not include specific

These instructions are limited to general topics of regulator component installation and may not include specific information pertaining to your application. These instructions are written assuming the use of an electric fuel pump

information pertaining to your application. These instructions are written assuming the use of an electric fuel pump capable of at least 15 PSIG outlet pressure and limited to the specified

capable of at least 15 PSIG outlet pressure and limited to the specified regulator has an internal spring that can be changed for other pressure ranges, including “L” range, for 1.5-3.5

regulator has an internal spring that can be changed for other pressure ranges, including “L” range, for 1.5-3.5 PSID, “T” range for 10-25 PSID, if required by the specific application. Higher, fuel injection pressure ranges are

PSID, “T” range for 10-25 PSID, if required by the specific application. Higher, fuel injection pressure ranges are recommended for a different model of regulator (unless for very high flow EFI applications). Visit our company

recommended for a different model of regulator (unless for very high flow EFI applications). Visit our company website for specific details pertaining to example fuel systems and other solution ideas. Additional information

website for specific details pertaining to example fuel systems and other solution ideas. Additional information including advanced troubleshooting, any special alerts and FAQ’s pertaining to this and other products is also

including advanced troubleshooting, any special alerts and FAQ’s pertaining to this and other products is also available.

available.

2.5 GPM at 5 PSID

(570 LPH at 0.35 Bar)

Pressure Range “E”

4-12 PSID

(0.28-0.82 Bar)

(3X) -906 O-r ing

Adjustment Screw

Plug

Jam Nut

Flat Washer

(3X) Bracket Lock Washers

Regulator

Barbed Fitting

Maximum Flow Capacity

Bracket

(3X) Bracket Screws

(above). This

General Regulator Performance Notes:

The notation “PSIG” means pressure in Pounds per Square Inch (PSI) relative to the prevailing atmospheric

The notation “PSIG” means pressure in Pounds per Square Inch (PSI) relative to the prevailing atmospheric condition or outside air. This is referred to as Gauge Pressure. The notation “PSID” means pressure in PSI relative

condition or outside air. This is referred to as Gauge Pressure. The notation “PSID” means pressure in PSI relative

Pressure Reference Port

to another pressure source or called the Differential Pressure (relative to

to another pressure source or called the Differential Pressure (relative to pressure ratings). This regulator acts as a relief valve to control pressure (returning fuel back to fuel cell). Only

pressure ratings). This regulator acts as a relief valve to control pressure (returning fuel back to fuel cell). Only “blow-through” boosted applications for carbureted systems should have a line plumbed to the pressure reference

“blow-through” boosted applications for carbureted systems should have a line plumbed to the pressure reference port. The amount of pressure difference to expect with application of full throttle compared to idle (for naturally

port. The amount of pressure difference to expect with application of full throttle compared to idle (for naturally aspirated engines) is a function of how much flow the engine is using (reference

aspirated engines) is a function of how much flow the engine is using (reference calculations).

calculations).

Pressure Reference Port

Regulation Slope

105020124-1, No Rev Page 1 of 4

in case of

, above for

Plumbing Planning Notes:

Minimize plumbing restrictions between carburetor(s) and regulator for peak performance. Use –6AN (3/8”) to

Minimize plumbing restrictions between carburetor(s) and regulator for peak performance. Use –6AN (3/8”) to –10AN (5/8”) line as required per flow rate requirements of the vehicle’s engine and fuel pump. See company web-

–10AN (5/8”) line as required per flow rate requirements of the vehicle’s engine and fuel pump. See company website for nitrous oxide use and alternate plumbing schematics. Plumb the return line back to the fuel tank. Use of a

site for nitrous oxide use and alternate plumbing schematics. Plumb the return line back to the fuel tank. Use of a –8AN (1/2”) return line is typically recommended for this model of regulator. See diagram on next page as well as

–8AN (1/2”) return line is typically recommended for this model of regulator. See diagram on next page as well as diagram below, to identify the ports used on the regulator. The two side ports can be interchanged either Outlet or

diagram below, to identify the ports used on the regulator. The two side ports can be interchanged either Outlet or Inlet, since this valve operates as a relief valve (pressure is relieved from the regulator out to the rest of the fuel

Inlet, since this valve operates as a relief valve (pressure is relieved from the regulator out to the rest of the fuel system, by returning unused fuel back to the fuel cell). Plumb the Pressure Reference Port using the barbed fitting

system, by returning unused fuel back to the fuel cell). Plumb the Pressure Reference Port using the barbed fitting for “blow-through” carbureted applications only (blow-through means that a turbo or supercharger is used to

for “blow-through” carbureted applications only (blow-through means that a turbo or supercharger is used to pressurize the carburetor(s)). When this occurs, fuel pressure must be compensated by the change in float bowl

pressurize the carburetor(s)). When this occurs, fuel pressure must be compensated by the change in float bowl pressure. If motor is naturally aspirated (Normal carbureted application, with float bowl vented to atmosphere) allo

pressure. If motor is naturally aspirated (Normal carbureted application, with float bowl vented to atmosphere) allo this port to vent to atmosphere, do not plug or plumb to any pressure source. The fuel line used must handle high

this port to vent to atmosphere, do not plug or plumb to any pressure source. The fuel line used must handle high pressure. The use of fuel line such as stainless steel braided line and “AN” style fitting connections is

pressure. The use of fuel line such as stainless steel braided line and “AN” style fitting connections is recommended. The fuel ports (two –6AN Inlet-Outlet Ports and one –6AN Return Port) use “AN” or “military” style

recommended. The fuel ports (two –6AN Inlet-Outlet Ports and one –6AN Return Port) use “AN” or “military” style fittings. This plumbing standard is commonly used with racing and high performance applications. See step 6 on

fittings. This plumbing standard is commonly used with racing and high performance applications. See step 6 on next page for additional information on this port standard. A fuel filter with a 60 micron or lower particle rating is

next page for additional information on this port standard. A fuel filter with a 60 micron or lower particle rating is required to be used upstream of regulator and downstream from fuel pump to protect it and the carburetor from

required to be used upstream of regulator and downstream from fuel pump to protect it and the carburetor from foreign object damage. Reference the Schematic Diagram below for filter locations. Use of a liquid filled gauge

foreign object damage. Reference the Schematic Diagram below for filter locations. Use of a liquid filled gauge exposed to engine compartment heat is not recommended as the liquid inside the gauge may exert measurement

exposed to engine compartment heat is not recommended as the liquid inside the gauge may exert measurement

DO NOT

errors.

errors. burst can spill fuel inside passenger compartment and on occupants, possibly causing serious injury or death. An

burst can spill fuel inside passenger compartment and on occupants, possibly causing serious injury or death. An electric gauge or pressure transducer system is recommended for readings in a passenger compartment.

electric gauge or pressure transducer system is recommended for readings in a passenger compartment.

Typical Carbureted Fuel System Schematic Diagram:

Use Y-Block or Fuel Log

Multiple Float Bowls

Fuel Gauge Shown

in Gauge Port, Liquid

have Error Due to

Temperature Variations.

Installation Step s:

DO NOT

to Split Flow for

Filled Gauge may

plumb gauge port to any gauge mounted inside the vehicle or in passenger compartment. A line

51504 Regulator

Tank must be Plumbed According

Specifications and Recommendations .

Straining Filter Recommended. Straining

Consult Pump Manufacturer's Specifications.

To Induction Tube (for BlowThrough Applications Only!, Otherwise Do Not Plumb or Plug)

Follow Fuel Cell Manufacturer's

Recommendations for Proper

Vented Fuel Cell or Fuel Tank.

to Maximum Pump Flow Rate.

Consult Pump Manufacturer's

Fuel Straining Filter Required, Typical

Micron Rating: 100-250, Fuelab

Filter may be Installed in Fuel Pump,

Fuel Filter Required, 60 Micron Stainless Steel Element for Methanol Use or 10 Micron Paper Element for Gasoline. Fuelab Filter is Recommended.

Electric

Fuel Pump

Cell Vent Plumbing

1. Disconnect the ground terminal from battery and allow the vehicle’s engine and exhaust system to cool.

1. Disconnect the ground terminal from battery and allow the vehicle’s engine and exhaust system to cool. Relieve fuel system per applicable service manual. Follow all Warnings and Cautions written on previous page

Relieve fuel system per applicable service manual. Follow all Warnings and Cautions written on previous page of these instructions.

of these instructions.

2. Modify, remove or replace other fuel system components as required per established build plan (reference

2. Modify, remove or replace other fuel system components as required per established build plan (reference notes on previous page and above).

notes on previous page and above).

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Fuelab 51504 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual