anyone know the flow rate of the stock lift pump?

4-7psi at idle, 0psi at WOT. If thats what you mean.

921stgen's Sig:

91.5 W250 rusty P.O.S., pods, no afc, pull cable, AM electric FP gauge, Isspro boost, pyro, 366 spring, 91 W350 parts truck, sold-92 W250, 4" lift, 5" AEM intake, 4" exhaust 5" stack, Bully Dog Fuel Pin, pull cable, 366 spring, AM electric FP gauge, Isspro boost, pyro, tach

that'd be pressure specs; not the flow rate... but i do have to ask why does flow rate really matter? in order to have pressure there has to be a restriction, or an abundant supply. as long as there's pressure then you have plenty of potential for flow; i say potential b/c the pump uses the return line as it's restriction. if there is a restriction before the pump then you won't get the same flow to the pump. best way to describe the flow rate of the stock lift pump... too little for anything but a stock truck.

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if i did the math correctly; when bobby posted the fuel system manual the spec for the lift pump is .70 quarts in 30 seconds at cranking speed. which is 2.8 quarts per 2 minuets; or 84 gal/per hr.

tower_ofpower's Sig:

One thing i learned in college: DON'T!!! stick your fingers where you wouldn't stick Mr. Happy 89' W250, full fuel 1 1/2 turns, smoke screw needs adjustment, M&H M3 fuel pin and timing spacer, 366 spring, air dog 150,3" DP to 4" DP back bully dog exhaust with the front baffle cut out. Soon to be:transmission upgade, turbo and manifold swap, and injectors.

well i have a 4bt in my truck and the guys still think i need a better liftpump.The factory liftpump the same part as the 6bt.How can my 4bt run out of fuel when theyre designed for a 6bt?Ive gotta get a fuel guage in the cab so i can see whats going on at higher loads.

yer talkin the mechanical pump driven off a cam lobe????

flow rate is important but its expensive to measure flow, the easiest way is to measure the pressure as pressure is simple the resistance to flow....................easier put is to take an open ended garden hose and turn the valve 100% open.............the water will flow like crazy in GPM but will have little pressure since there is no resistance to flow........then take yer thumb and place it over the end of the hose, this will create resistance and the flow rate will drop (GPM) and the pressure will increase

clear as mudd now

bottom line get a fuel psi gauge and monitor that......if the pressure gets low during hard acceleration then yer pump or system has issues and needs attention

Whit's Sig:

* 01 Cummins/Dodge/HO/6 speed*275 injectors*PDR 35 turbo w/14cm housing & high pressure boots*HTT 3 piece ported exhaust manifold*Progaurd 7 with prefilter*Edge Comp*Fass II*Southbend con OFE*Jacobs brake*5"Stacks Big ens*E/F shift knob w/2low & brake switch*10 Gages*KW Ram air System cab controlled*Rickson 19.5x265's*True speed calibrator*Rancho 9000's*DT track bar*DSS steering stabilizer*KW Side impact rails*KW Traction Bars*Toolbox/fueltank 60 gal Combo*Mag High Tech Diff Cover*Ranchand bumpers*Grover air horns*Rear Wheel Cylinder Upgrade DYNO 375 Horse 941 Torque

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0.75L (max) / 30 sec
3-5psi

That is straight from teh factory service manual. You pump will take around 15psi to the inlet w/o issue. Runs better like that too.

Here is what the FSM has to say about the fuel system

1st Gen Factory Fuel System

The spec I found was at teh bottom of the last page. I would download it and print it out, easier to read like that.

RSWORDS's Sig:

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