Fuelab 56502 User Manual

Model Number 56502-c

Fuel Pressure Regulator

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 applicabl e

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. Proper eye and personal protection is required at all times during installation.

Plug

Jam Nut

Filter

Regulator

Barbed Fitting

Bracket

(3X) Bracket Screws

(3X) Bracket Lock Washers

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

56502-c Features and Performance Ratings:

Inlet Port Sizes -10AN Military Port

Return Port Size -10AN Military Port

Regulation Slope < .5 PSI/GPM

Maximum Flow

Capacity
Pressure

Adjustment Range

5.0 GPM at 5 PSID

(1100 LPH at .35 Bar)

Pressure Range “E”

4-12 PSID

(.3 – .8 Bar)

(3X) -910 O-ring

Adjustment Screw

Flat Washer

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
information pertaining to your application. These instructions are written assuming the use of an electric fuel pump
capable of at least 20 PSIG outlet pressure and limited to the specified Maximum Flow Capacity (above). This
regulator has an internal spring that can be changed for other pressure ranges, including “T” range, for 12-25 PSID
and “E” range for 25-65 PSID, if required by the specific application. Visit our company 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 available.

General Regulator Performance Notes:

The notation “PSIG” means pressure in Pounds per Square Inch (PSI) relative to the prevailing atmosp heric
condition or outside air. This is referred to as Gauge Pressure. The notation “PSID” means pressure in PSI relative
to another pressure source or called the Differential Pressure. Only “blow-through” boosted applications for
carbureted systems should have a line plumbed to the pressure reference port (Plumbed to induction tube, same
pressure as float bowl vent). “Blow-through” applications will have limitations based on inlet fuel pressure and bo ost
pressure. 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 Regulation Slope, above for
calculations). The actual readings of pressure in a real world application would show a lower pre ssure, as the
engine is using fuel that would normally be returning back through the return line when the engine is off or at idle.

105020622-1, No Rev Sheet 1 of 4

Plumbing Planning Notes:
Minimize plumbing restrictions between carburetor(s) and regulator for peak performance. Use –8AN (1/2”) to
–10AN (5/8”) line as required per flow rate requirements of the vehicle’s engine and fuel pump. See company web-
site for nitrous oxide use and alternate plumbing schematics. See diagram on next page as well as diagram below,
to identify the ports used on the regulator. Plumb the return line back to the fuel tank. Use of a –8AN (1/2”) or -
10AN (5/8”) return line is typically recommended for this model of regulator. Plumb the Pressure Reference Port
using the barbed fitting for “blow-through” carbureted applications only, “blow-through” means that a turbo o r
supercharger is used to 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) allow this port to vent to atmosphere, do not plug or plumb to any pressure source. Use of supplied
port filter is shown below. 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 recommended. The fuel ports (two –10AN Inlet/Outlet Ports
and one –10AN Return Port) use “AN” or “military” style 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 40 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 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 errors. DO NOT

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

Typical Carbureted Fuel System Schematic Diagram:

Typical Dual Inlet
Carburetor Shown

Y-Block or Fuel Log,

to Split Flow into

Multiple Fuel Bowls

56502-c Regulator

Fuel Gauge Shown in

Gauge Port, Liquid Filled

Gauge may have Error Due

to Temperature Variations.

Follow Fuel Cell Manufacturer's

Recommendations for Proper

Vented Fuel Cell or Fuel Tank.

Tank must be Plumbed According

to Maximum Pump Flow Rate.

Specifications and Recommendations.

Consult Pump Manufacturer's

Fuel Straining Filter Required, Typical

75 Micron Filter Recommended. Straining

Consult Pump Manufacturer's Specifications.

Fuel Filter with 60 Micron or
Lower Particle Rating is Required.
Fuelab Filter with 6, 10 or 40
Micron Rating is Recommended.

Micron Rating: 75-150, Fuelab

Filter may be Installed in Fuel Pump,

Fuelab Prodigy 41403 Series

Fuel Pump Recommended.

Fuel Pump,

Cell Vent Plumbing

Installation Steps:

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
of these instructions.

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

notes on previous page and above).

3. Use the supplied bracket as a drilling template to mark holes for mounting bracket. Choose a location that

minimizes exposure to excessive heat, near carburetor(s). Mounting bracket can be modified as required.

105020622-1, No Rev Sheet 2 of 4