AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 137)

Page 137 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
near battery cables. Use clamps to secure AN hose every 15 inches, or 24 inches if a rigid tube
is used.
The following table will help you determine which hose size is correct for your application: These
sizes are based on a nominal fuel pressure of 40 psi.
Fuel Delivery Hose Sizes
Gasoline Powered Engines
Up to 499 HP .344” hose -6AN
500 - 799 HP
.437” hose
-8 AN
900 – 1100 HP .562” hose -10 AN
Methanol Engines
Up to 499 HP .437” hose -8 AN
500 - 799 HP
.562” hose
-10 AN
900 – 1100 HP .687” hose -12 AN
The above table should be used for typical passenger car applications. However, for custom
applications the hose run length will affect fuel delivery. If you have a long hose run, then the
actual flow will have to be determined by running the fuel pump into a graduated cylinder, then
measuring the flow vs. time and calculating the flow in gallons per hour (g/h). Also note that if
fuel banjos are used in the system be sure they have adequate fuel flow capability.
The fuel return hoses should be one size smaller than the delivery hose. For the sample engine
described above, we would use a .437” (-8) delivery hose and a .344” (-6) return hose.
Fuel Filter and Fuel Rail
Often overlooked in EFI installations, the fuel filter must have the capacity, filtering efficiency
and burst strength to withstand the pressures of an EFI system. It must be able to flow the