Power Level of a 255 Fuel Pump and Plus 40 injectors

[OMZILLA]

So im sure that this has been asked before but how much power can u make on a 255 in tank fuel pump and a set of plus 40 injectors / how much power can you make before you run out of fuel ?

[83scamp]

That's kind of a loaded question. Depends on how the rest of your setup is put together... You need a matching intake, heads, turbo, etc, to make it work. The combo has to fit together to make power...

[chromguy]

My theoretical calculations say you should not run out of fuel

the 255L/hr can deliver over 210L/hr at 80psi (25psi boost)
210L/hr * 0.75(gasoline average density) *2.205lb/Kg =
350 lbs of fuel per hour.

Now the four +40 can use 52lb/hr at 55psi so approx 220lbs/hr at 55psi. If one assumes a linear relationship (good enough for our discussions here) of flow from 55 to 80psi, the fuel will increase 1.45X
So that is approx 320lbs/hr

That is a bit to close for me as the pump will weaken as it gets older. Personally I would recommend a 50% extra head room. On a realistic note, getting 25psi at the intake manifold is challenging due to upstream pressure losses such as TB, tubing, IC etc.

The Walbro 255L/hr pump is rated to 500+ hp according to their documents.

The previous owner of my 88 Shelby Z with a S60 at 18 psi (255L/hr and +40 injectors etc) was claimed to be in the 300hp range.

How much HP you get will depend....like 83scamp says.

[contraption22]

As noted, as your fuel pressure rises, the pump's capacity for volume decreases. Adequate voltage to the pump is also critical.

[chromguy]

Oh and remember that the fuel line/filter and rail also contribute to a pressure drop leading to decreased flow from the pump as it further raises the delivery pressure. If this is a concern, you should increase the fuel lines ID

Contraption22, what gauge fuel line power/ground line do you recommend? I was considering upgrading my stock wires to the pump.

[contraption22]

Generally people like to use 10awg wire to feed the pump.

-6 line should be sufficient for up to 500-600hp.

I like to run a larger injector than you'll really need to run 40-45 psi base fuel pressure to ease up the work the pump has to do.