FORM 1527 (REV. B) 06/01 INSTALLATION INSTRUCTIONS ® COMPETITION FUEL PRESSURE REGULATOR FOR FUEL INJECTION PART NO. 4305M IMPORTANT: This regulator must use a fuel return line. The fuel return line runs between the fuel bypass port of the regulator and the fuel tank. Fuel pressures cannot be adjusted if the fuel return line is absent. PARTS INCLUDED IN THIS KIT 1 1 2 2 2 2 Fuel Pressure Regulator Bracket Bracket Mounting Screws 3/8" NPT Pipe Plugs AN-8 Fittings O-rings for Fittings SPECIFICATIONS: Port thread sizes: 3/8" NPT and AN-8 Adjustment range: 30-100 PSI Fuel Application: Gasoline and Alcohol/Methanol GENERAL INFORMATION Mallorys 4305M regulator regulates fuel pressure between high pressure fuel pumps and fuel injection systems. The regulator is recommended for Mallory COMP PUMP® 60FI, 110FI, or any fuel injection pump designed to produce 30-100 PSI. The 4305M regulator is a return style fuel pressure regulator. The excess fuel and fuel pressure is sent back to the fuel tank through the fuel return line. The fuel return line runs between the fuel bypass port of the regulator and the top of the fuel tank. The fuel tank must have provisions for a fuel return line. This regulator is equipped with a vacuum/boost compensation port (brass barb fitting) that can be used to momentarily decrease fuel pressure (vacuum compensation) at idle and part throttle, or increase fuel pressure under blower boost (boost compensation). While it is not necessary to connect a hose to the vacuum/boost compensation port, it may be beneficial in some cases. However, the small plug on the barb must be removed before use. You can mount the 4305M regulator at any angle. For maximum efficiency, mount it as close as possible to the fuel injection system. DO NOT mount the regulator on or near exhaust manifolds. A bracket is provided for convenient mounting. ADJUSTMENT SCREW JAM NUT VACUUM/BOOST COMPENSATION PORT (3/16" O.D. BRASS BARB FITTING) REGULATOR CAP REGULATOR HOUSING OUTLETS TO INJECTION (3 PLACES, 3/8" NPT) UNUSED PORTS MAY BE PLUGGED OR USED AS GAUGE PORTS BRACKET MOUNTING HOLES (2) INLET PORT FROM PUMP (AN-8) FUEL BYPASS PORT (AN-8) INSTALLING THE 4305M REGULATOR FUEL LINE SIZE (FROM PUMP TO REGULATOR) 1. Connect the fuel line and the return line. The return line Fuel line size is determined by the horsepower of the enmust be attached to the bottom port on the regulator. The gine. fuel line must be attached to the upper -8AN port on the Up to 350 HP: 5/16" or 4AN regulator. Fittings must be purchased to adapt the fuel Up to 500 HP: 3/8" or 6AN line and the return line to the regulator. The unused port(s) Up to 700 HP: 1/2" or 8AN in the regulator can be plugged or used as gauge port(s). Up to 1200 HP: 5/8" or 10AN 2. Turn the fuel pump on and check for leaks. If leaks are RETURN LINE SIZE found on the NPT (tapered) fittings, make sure the threads The size of the return line is determined by the output of are covered properly with Teflon sealer. the fuel pump. NOTE: If the fuel system will not prime properly, back the adjustment screw all the way out of the regulator until the system is primed. Then reinstall the adjustment screw. Up to *29 gal/hr (110 liter/hr): Up to *45 gal/hr (170 liter/hr): Up to *90 gal/hr (340 liter/hr): Up to *180 gal/hr (680 liter/hr): 1/4" or 3AN 5/16" or 4AN 3/8" or 6AN 1/2" or 8AN 3. Connect the vacuum hose that was originally connected * Pump output at 40 psi. to the stock regulator to the small nipple on the Mallory PUMP SIZE regulator. This will reduce fuel pressure at idle and during Pump size is determined by horsepower. light-throttle cruise. Multiply horsepower by .083 to determine pump size in gal4. Set the fuel pressure. Loosen the jam nut on the top of lons per hour. the regulator and turn the brass adjustment screw to adjust the pressure. Clockwise increases pressure. Example: 500 HP x .083 = *42 gal/hr Multiply horsepower by .314 to determine pump size in liters per hour. Example: 500 HP x .314 = *157 liters/hr *Pump output at 40 psi. NOTE: Add 25% larger pump for supercharged applications. MALLORY IS A DIVISION OF THE MR. GASKET PERFORMANCE GROUP 550 MALLORY WAY, CARSON CITY, NEVADA 89701 (775) 882-6600 FAX (775) 887- 4326 www.mrgasket.com FORM 1527 (REV. B) 06/01 Made in U.S.A. Printed in U.S.A.