AEM 30-71XX Infinity Stand-Alone Programmable Engine Mangement System Full Manual - Manual (Page 309)

EFI Components 303
© 2014 AEM Performance Electronics
Fuel System Setup
Fuel Plumbing
Even with proper injector and fuel pump sizing, a fuel system will not flow adequately unless the
hoses that deliver the fuel to the fuel rail are of sufficient size and are routed properly. On systems
that use the PNP version of the AEM Infinity, there is no need to replace the fuel delivery hoses
unless the engine is heavily modified.
NEVER route fuel hoses through the interior of a car. Put bluntly, this is a dangerous thing to do.
Whenever possible, use a delivery tube to make the connection from the pump discharge to the
filter in the front of the car. The lines should be rated to withstand at least twice the maximum
pressure of the EFI system.
Using the above parameters of our sample engine with moderate boost, we expect to see
pressures in the 65–70 psi range. This will require a line with at least 140-psi rating (most AN
hoses exceed this by a large margin). When routing fuel lines, it is imperative that they are
protected from road hazards and the exhaust system. The fuel line should NEVER be routed
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 -6 AN
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 AN) delivery hose and a .344” (-6 AN) return hose.