Walbro 255lph Fuel Pump
#5
Evolving Member
iTrader: (3)
Here is AEM's answer by the numbers for fuel pumps:
(Estimated HP x BSFC) x (1 + Safety Margin) = pounds/hour
pounds/hour / 7.25 = gallons/hour
gallons/hour * 3.785 = lph
BSFC refers to the efficiency of the engine. They suggest .65 to .68 for forced induction.
The recommended safety margin is .30 to give you a comfortable net to work with.
The 7.25 is the estimated weight of a gallon of fuel (gasoline) for conversion. If you are using something else (Meth, E85, Water, Nitrous, etc), this will change.
Let's assume your end goal is 500hp.
500hp x .65 x 1.3 / 7.25 = 58gal/hr * 3.785 = 220.6lph
This leaves a pretty big cushion for you to work with.
Or we could work it backwards, knowing that the Walbro outputs 255lph...
255/3.785 = 67.37gal/hr * 7.25 = 488.44lbs/hr / (1.3 x .65) = 578.04hp
So this would mean that the 255lph Walbro is good up to 578hp on gasoline with a .3 margin of safety.
(Estimated HP x BSFC) x (1 + Safety Margin) = pounds/hour
pounds/hour / 7.25 = gallons/hour
gallons/hour * 3.785 = lph
BSFC refers to the efficiency of the engine. They suggest .65 to .68 for forced induction.
The recommended safety margin is .30 to give you a comfortable net to work with.
The 7.25 is the estimated weight of a gallon of fuel (gasoline) for conversion. If you are using something else (Meth, E85, Water, Nitrous, etc), this will change.
Let's assume your end goal is 500hp.
500hp x .65 x 1.3 / 7.25 = 58gal/hr * 3.785 = 220.6lph
This leaves a pretty big cushion for you to work with.
Or we could work it backwards, knowing that the Walbro outputs 255lph...
255/3.785 = 67.37gal/hr * 7.25 = 488.44lbs/hr / (1.3 x .65) = 578.04hp
So this would mean that the 255lph Walbro is good up to 578hp on gasoline with a .3 margin of safety.
#6
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Join Date: Feb 2004
Location: Redmond - Lake Tapps ,WA
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Gas the 255 is OK, injectors are too small though - 880's would be better, and at that point go BIG anyway.
E85 the single pump won't work, and you need some 1200 or bigger injectors.
E85 the single pump won't work, and you need some 1200 or bigger injectors.
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