AEM 30-71XX Infinity Stand-Alone Programmable Engine Mangement System Full Manual User Manual
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© 2014 AEM Performance Electronics
Infinity User Manual
Methanol (alcohol) powered engines require twice the amount of fuel, so the BSFCs are
doubled.
Calculating the total fuel requirement of an engine requires simple equations that we outline in
the following section. You must know how much power the engine is anticipated to make and we
recommend that you guess on the high end. The fuel requirement will be determined in pounds
per hour of fuel flow. Since most pumps are rated in gallons/hour you must know the weight of
your fuel/gallon. (The vast majority of gasoline based fuels run at 7.25 lbs./gallon.) The equations
to determine your fuel requirement is as follows:
(Power x BSFC) x (1 + Safety Margin) = pounds/hour
Pounds/hour / 7.25 = gallons/hour
An example of this equation is:
500 hp gasoline engine using moderate boost with a 30% safety margin
(500 x .625) x 1.30 = 406.25 lbs/hr
406lbs/7.25 = 56 gallons/hour
If the pump that is being considered is rated in liters per hour, use the conversion factor of
3.785l/gallon. The pump described above would be rated at 56 gallons x 3.785 liters =
211.96 liters/hour.
In the fuel pump sizing, always use a safety margin greater than 20%.
The fuel pump should be located at a level that corresponds to the lowest part of the fuel tank.
This does NOT mean that the pump should be in a vulnerable position such as hanging below
the tank. The pump should also be positioned so that it is protected from the road hazards
(speed bumps, curbs, road debris, etc.). In the event of an accident, the vehicle structure around
the fuel pump should not deform to a point where the pump and its electrical connections are
compromised.
The wiring for the fuel pump MUST be rated for the amperage of the pump. As with all high
current wiring, a fuse rated for the amperage of the pump should be used. It is always better to
err on the large side for the wire size. The ground for the pump must be the same size as the
power lead and be mounted to a location that is clean and clear of any undercoating or paint.