question about fuel

okietheranger · Mar 14, 2015

hey guys havnt been here in a few years but I have a question to ask, anyone running a v-8 in there ranger and using the stock 2.9 fuel pump in the tank and on the rail and having any problems with that set up?

RonD · Mar 14, 2015

If 45psi system then a Mustang 5.0l stock fuel pump was rated as 25 GPH(gallons Per Hour)
2.9l fuel pump was rated as 20 GPH minimum at 45psi.

But.............stock 5.0l generates 215 Horse power
You can use that to calculate GPH needed, that is what car makers do.
Naturally aspirated engine uses roughly 0.5 pounds of fuel to make 1 hp for 1 hour at Wide Open Throttle.

Formula is HP x 0.5(fuel)/6 = GPH needed at wide open throttle
So 215 x .05/6 = 17.9 GPH

So you should be fine, but pumps do get old.

Generally having reduced power at higher speed or pulling loads can be clogged exhaust or dirty fuel filter

okietheranger · Mar 15, 2015

So here is my issue. I've done a few mods to the engine. Afr 165 heads 76mm throttle bottle egr cooler and mass air. Have a bama tune headmen headerss I installed a bbk high flow pump in the tank along with the stock high pressure stock 2.9l pump on the rail. New 19# accel injectors new fuel reg. new map sensor edelbrock upper and lower 2 intake scorpion roller rockers. It feels like it wants to rip ass but somthing is holding it back. Even with the high flow bbk mustang pump in the tank (even if I bypass the stock 2.9 pump on the rail. It will only get 15 psi of fuel pressure and wil not hold it. If I run them both. I will have about 35 pounds of pressure and it will run and run fine. But I feel like it needs more. I'm stinking lost

alwaysFlOoReD · Mar 15, 2015

I don't know a lot about fuel systems but according to Rons formula it sounds like you're running out of volume at higher rpms.
300 hp * .5 / 6 = 25 GPH
@ RonD; what is the .5 and 6 for in your formula?

okietheranger · Mar 15, 2015

That's what it sounds like to me. But I'm stumped. Why wouldn't it run with the aftermarket fuel pump. I should be able to run the tank pump alone and be fine.

alwaysFlOoReD · Mar 15, 2015

What are the specs of the aftermarket pump?

sent while sitting on the throne

okietheranger · Mar 15, 2015

It's a bbk hi volume part number 1607

RangerSVT · Mar 15, 2015

How are you bypassing the ranger rail pump, unplugging the electrical connector, or removing the fuel lines from the pump and connecting the lines together?

SVT

RonD · Mar 15, 2015

alwaysFlOoReD said:
I don't know a lot about fuel systems but according to Rons formula it sounds like you're running out of volume at higher rpms.
300 hp * .5 / 6 = 25 GPH
@ RonD; what is the .5 and 6 for in your formula?

For the 0.5

Brake Specific Fuel Consumption or B.S.F.C. is the amount of fuel required to produce 1 HP for 1 hour. This means that an engine with a B.S.F.C of .5 will burn 1/2 or .5 lbs of fuel to produce 1 HP for one hour. Determining exact B.S.F.C for a specific engine is complicated and requires an engine dyno.

Based on industry standards the B.S.F.C for:

Naturally Aspirated:
Gasoline – .45 to .50
E85 – .63 to .70
Methanol – .9 to 1.0

Boosted or forced induction:
Gasoline – .60 to .65
E85 – .84 to .91
Methanol – 1.80 to 2.0

The 6 is the 6 pounds that a gallon of gasoline weighs, actually 6.1 or 6.2 for regular and 6.3 for premium, depends on water content, lol.

(horse power) * (B.S.F.C.) / (weight of gallon of fuel) = GPH at WOT

Not included is the fuel pressure, as pressure goes up flow goes down.
Think of putting your finger over the end of a garden hose to spray water farther or harder, you get less flow but more pressure.
So on fuel pumps you need to also look at the pressure rating used for the GPH, some use 6psi so show a higher GPH, than a pump that has GPH rated at 70psi

alwaysFlOoReD · Mar 15, 2015

your aftermarket pump;

Free Flow Rate: 255 lph

Maximum Pressure (psi): 90 psi

255 lph ~ 60 gph

Sounds to me that should work fine for your motor without the inrail pump.

@ RonD; thanks

RonD · Mar 15, 2015

okietheranger said:
It's a bbk hi volume part number 1607

This in tank pump is rated as 255 liters per hour(67GPH) at 0psi(free flow)
As pressure goes up flow goes down, I like to use 4GPH loss for each 10psi.
So 40psi system with this pump would be capable of 51GPH
70 PSI system 39GPH

4GPH is just a number I use, calculating pressure vs volume is a formula based on several factors, and there are charts you can look at if you want more exact figures

Yes, the frame rail pump sets the flow, wouldn't matter what pump was in the tank, so I would eliminate that frame rail pump.

Also check the fuel pump voltage, GPH is usually based on 13.5volts(engine running voltage), if voltage drops due to wire connector corrosion flow will drop as well, and it can drop quite fast, i.e. 2 volt drop can cut flow by 1/2

okietheranger · Mar 15, 2015

rangersvt I unplugged and removed the lines and connected them together. I know if I just unplugged it, it would be just like a brick wall :icon_twisted:

RonD · Mar 15, 2015

I think on the dual pump Rangers there was an "accumulator" that looked similar to a canister fuel filter, that should also be removed.
Basically you want:
in tank pump------------fuel filter-----------Fuel pressure regulator/fuel rail(assuming return, 40psi, system)

okietheranger · Mar 15, 2015

RonD said:
I think on the dual pump Rangers there was an "accumulator" that looked similar to a canister fuel filter, that should also be removed.
Basically you want:
in tank pump------------fuel filter-----------Fuel pressure regulator/fuel rail(assuming return, 40psi, system)

That's how it's set up. Are you talking about that black deal that's like a canister filter? It's removed.

RonD · Mar 15, 2015

Yes, that's the part, and yes it wouldn't be needed with 40psi in tank pump.

I assume you are running a 40psi system with FPR and return line, or are you running 70psi returnless?

What horse power do you think you have?
And what injectors?

question about fuel

New Member

Official TRS AI

New Member

Forum Staff Member

New Member

Forum Staff Member

New Member

Oct 09 OTOTM

Official TRS AI

Forum Staff Member

Official TRS AI

New Member

Official TRS AI

New Member

Official TRS AI

Sponsored Ad

Sponsored Ad

Member & Vendor Upgrades

Truck of The Month

Recently Featured

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store

Sponsored Ad

Sponsored Ad

Sponsored Ad

Amazon Deals