Floscan Pre-Installation Manual for Diesel Models - Manual (Page 6)

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6
Forward Fuel Flow Lines
Careful planing, good plumbing practice, and a neat, orderly installation are required to successfully keep the fuel systems
inlet vacuum under 10” Hg, (5 PSI). To achieve this you must:
• Size forward fuel lines and fitting I.D.’s, to keep fuel velocities between 2, and 4 feet per second.
• Make plumbing runs short and direct.
• Make radius bends in pipe or hose instead of using elbow fittings. Elbows will add the equivalent of seven + feet of fuel
flow restriction to the system. They also generate turbulence.
• Use only, “Full Flow” hose fittings.
• Use hose of adequate length. Don’t connect two or three shorter pieces together.
• Mount pulsation dampers no higher than necessary.
• Size Racor type fuel filters to minimize their pressure drop. It may be necessary to oversize the filter by 150%, or
parallel two smaller filters.
Fixed pressure drops from the fuel tank lift pipe, suction screen, and flow sensors total approximately 5” Hg. This allows 5”
Hg. for hose and pipe plumbing, Racor filter, and pulsation damper. If total inlet vacuum exceeds 10” Hg, the engine may be
difficult to start and fuel starvation may occur at higher Rpm’s.
Approximate Maximum Flow Rates through Schedule 40 Pipe & Fittings for Selected Line Velocity
Pipe/Fitting Size 2 Ft/Sec. 4 Ft/Sec. 10 Ft/Sec. 15 Ft/Sec.
1 / 8” .269” ID 21.6 GPH 43.2 GPH 108 GPH 162 GPH
1 / 4” .364” ID 36.0 GPH 72.0 GPH 180 GPH 270 GPH
3 / 8” .493” ID 72.0 GPH 144 GPH 360 GPH 540 GPH
1 / 2” .622” ID 115 GPH 228 GPH 570 GPH 840 GPH
3 / 4” .824” ID 206 GPH 396 GPH 960 GPH 1,500 GPH
1” 1.049” ID 330 GPH 660 GPH 1,620 GPH 2,460 GPH
1-1 / 4” 1.660” ID 564 GPH 1,140 GPH 2,820 GPH 4,200 GPH
Table 1
Approximate Maximum Flow Rates through Fuel Hose for selected Line Velocity
Fuel Hose Size 2 Ft/Sec. 4Ft/Sec. 10 Ft/Sec. 15 Ft/Sec.
3 / 8 ~ .375” ID 36.0 GPH 72.0 GPH 180 GPH 270 GPH
1 / 2 ~ .500” ID 72.0 GPH 144 GPH 360 GPH 540 GPH
3 / 4 ~ .750” ID 180 GPH 360 GPH 900 GPH 1,500 GPH
1 ~1.000” ID 291 GPH 582 GPH 1,458 GPH 2,190 GPH
Table 2
Approximate Pressure Drop per Foot of Hose & Schd. 40 Pipe @ Selected Flow Rate and Line Velocity
2 Ft/Sec. 4 Ft/Sec. 10 Ft/Sec. 15 Ft/Sec.
Hose size PSI GPH PSI GPH PSI GPH PSI GPH
3 / 8 <.1 PSI @ 36 GPH .1 PSI @ 72 GPH 0.6 PSI @ 180 GPH 1.1 PSI @ 270 GPH
1 / 2 <.1 PSI @ 72 GPH .1 PSI @ 144 GPH 0.5 PSI @ 360 GPH 1.0 PSI @ 540 GPH
3 / 4 <.1 PSI @ 180 GPH .1 PSI @ 360 GPH .35 PSI @ 900 GPH 1.0 PSI @ 1,500 GPH
1 <.1 PSI @ 291 GPH .1 PSI @ 582 GPH .23 PSI @ 1,458 GPH 0.5 PSI @ 2,190 GPH
Table 3
Approximate Pressure Drop for 2 Full Flow Hose Fittings @ Selected Flow Rate and Line Velocity
2 Ft/Sec. 4 Ft/Sec. 10 Ft/Sec. 15 Ft/Sec.
Fitting-“ PSI GPH PSI GPH PSI GPH PSI GPH
3 / 8 <.1 PSI @ 36 GPH .10 PSI @ 72 GPH .55 PSI @ 180 GPH 1.2 PSI @ 270 GPH
1 / 2 <.1 PSI @ 72 GPH .13 PSI @ 144 GPH 1.0 PSI @ 360 GPH 1.5 PSI @ 540 GPH
3 / 4 <.1 PSI @ 180 GPH .14 PSI @ 360 GPH 1.3 PSI @ 900 GPH 2.0 PSI @ 1,500 GPH
1 <.1 PSI @ 291 GPH .10 PSI @ 582 GPH .45 PSI @ 1458 GPH 1.3 PSI @ 2,190 GPH
Table 4