Let's talk fuel pumps

[Powerstroker7.3]

Anything larger than 300/200s dual SD pumps don't keep up. I had them on mine and they were fine at anything less then 2.5ms of pulse. Anything more then that, basically WOT you're at 20ish psi. My fuel lab on low keeps 400/400s fed no problem at 75psi

What is the part number on your fuel lab cause I know they made several versions of it. I have to put my fuel lab on high speed to keep up with my 350/200s


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[96F350KID]

I have to look it up, which ever one says it suppprts 1300hp.

 

[Powerstroker7.3]

Oh yeah I know that one. Mine is only rated for 1000 hp


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[TARM]

This is what I have and its never had issue keeping up.

For more detailed info http://powerstrokearmy.com/forums/showthread.php?t=4230

IMO its one of the best ways to run any of these external pumps to keep them cool which has a significant effect on duty life. Make it liquid cooled while still keeping it external for easy access and surge tank ensures constant fuel feeding the pump regardless of tank fuel level or angle.

Currently I am working on relocating all but the lift pump to the engine bay by doing a battery relocation to over the rear axle.

On the tank I used compression fittings so I could go to JIC for the return as well.

 

[superpsd]

Very smart idea Tarm

 

[TARM]

Thanks. There were some benefits to doing research into the various systems the gas and alcohol guys use. There surge tanks are much more popular. The pencil to napkin flow diagram in that thread explains it.

One of the parts I really like is running the return line back thru the surge tank. It mixes with the other fuel keeping a more consistent temp but more so it adds flow volume to the surge tank for the high pressure fuel pump to have access to. WE actually use only a small % of the fuel we run thru the fuel rails in the heads. 90% end up back in the tank. This then is added to the fuel available to the pump itself. So even if you were one a severe angle where the tank PU is uncovered you would have a good deal of fuel before your pump inlet was uncovered. The surge tank does nto pressurize as the return lines flow thru it. That means the lift pump is working as atmosphere thru its free flowing which puts it at its max flow rate with the least strain on the pump system.

Having a inline fuel cooler also is nice since our fuel runs thru the heads which is some of the hots areas in the engine. I have thought of putting a bypass line with some valves for very cold winter days. Think how many times the fuel cycles thru the heads when you are at 1/4 tank using a 100 gph fuel pump. That can get your fuel hot hot hot. That decreases its lubricity protections. I know I posted it after I looked it up somewhere but IIRC ideal diesel fuel temp is suppose to below 100 F maybe in the 70s. Can not recall for sure but it makes sense. As fuel heats up it expands. As we inejct based on volume this means less BTUs or actual fuel density is getting into the cylinder. The more we can stabilize fuel temp IMO the better. Not to mention our fuel is what lubes the injectors.

What I want to see, if I can get it to fit, is putting the surge tank, HP filter, and dahl into the OEM battery locations. I will leave the lift pump on the rail close to the tank. I can use both sides so no big deal just need to ensure I have the height for them That damn dahl is huge but its performance is so good. It also allows for a heater if I wanted to add one.

AS this is an Excursion the dual battery case actually fits perfectly where the spare tire use to sit over the left rear axle. Put grounds to the frame.

 

[V-Ref]

a lot of folks do not know how gravity works.
unless the pump is under the tank it isnt going to be gravity fed

Umm....not quite

Maybe you can explain why there's positive fuel pressure at my hpop mounted regulator with zero elec power applied to the truck.

 

[kip4234]

I guess because the OBS trucks were not set up for electric fuel, I had the exact same issue it would hold pressure forever and I am not saying this is good or bad but I did not like it. I took my aeromotive regulator apart and used the tinest bit I don't remember the exact number but I am talking micro and drilled a hole in the inside of it per the aeromotive tech rep. Now my truck bleeds to zero after I turn it off.

 

[ju015dd]

Running dual sd's and havn't missed a beat:rockon:

 

[RBernardi]

Running dual sd's and havn't missed a beat:rockon:

That's clean do you happen to have any other pictures?

 

[m j]

Umm....not quite

Maybe you can explain why there's positive fuel pressure at my hpop mounted regulator with zero elec power applied to the truck.

if there is some, and I doubt it,
residual pressure from when the pump was running?
I would love to hear you explain it though

if you think you have invented anti gravity fuel, patent that **** Tesla.

 

[The Brad]

if there is some, and I doubt it,
residual pressure from when the pump was running?
I would love to hear you explain it though

if you think you have invented anti gravity fuel, patent that **** Tesla.

Truck is upside down!

 

[David N]

Anything larger than 300/200s dual SD pumps don't keep up. I had them on mine and they were fine at anything less then 2.5ms of pulse. Anything more then that, basically WOT you're at 20ish psi. My fuel lab on low keeps 400/400s fed no problem at 75psi

Thats odd. 350/200s here and my dual pump setup keeps up no problem. I've never noticed the needle move more than 1 or 2 psi.

 

[lincolnlocker]

I would put a sump on the truck too. Gravity flow will help keep the pump alive and not strain it as much plus it won't have to work as hard to make the desired pressure. Beans fuel sump is an easy install. You don't even have to drop the tanks


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ummm, been proven to be equal

Just wanted to point out there is no additional strain on properly setup siphon feed vs and sump feed. They are both gravity feed system and flow the same flow rate at the same head pressures based on the fuel hieght in tank. The ONLY time there is additional strain is when the siphon is started for the very first time or is broken. That only happens when you run out of diesel fuel in the tank not when you shut off the engine.

I known it seem logical that the pump has to pull fuel up the pipe all the time but it does not. Once the siphon is established it will keep flowing.

I even did a demonstration using a hose attached to the water jug vs one dropped over the edge to the bottom to establish a siphon. Timed them draining 1 gal of water. They were +/- 1 sec error rate.

Sumps can be handy when fuel levels are low sometimes as they give a bit extra in the sump catch.

But in terms of the vacuum / strain your pump has to pull to move fuel there is no appreciable difference between a sump and siphon.


There are also other ways that offer other benefits and take way liability and risk than going from traditional siphon to the sump setups used on the super duty tanks.

Surge tank with fuel pump intra-mount.

this right here!

Denis at strictly has backed that up..

Yes, all i did was remove the tee and placed the fuel lab in its place and wire it up. People think that if they dont loose smoke under load they still have fuel pressure. Everything in my truck is on a data logger and bothe obs trucks i have pull truck and drag/street truck have 350cc+ injectors and dual pumps never kept up WOT runs ever.

that is the first I have ever heard of dual stockers not keeping up. other than whatever hrt had in his old red truck for injectors is the only other time I have heard of duals not keeping up..

Running dual sd's and havn't missed a beat:rockon:

that is very very nice!! is that home made or someones setup? very curious cuz I need to do this to my dually eventually..

live life full throttle

god bless america and the farmer who feeds your fat ass

 

[The Brad]

Looks like a Strictly Diesel set up. I have one sitting in my garage just waiting to be installed.

 

[TARM]

You can get fuel flow at the hieght of the HPOP possibly and if it does you have to consider the entire system routing in terms of height and return. Its possible that once you have fuel flow up to and thru the point the return feed to the tank is creating the pressure drop and thus allowing for the fuel flow.

Here is a way to see drain hose system so only fuel is in the tank. Reprime just the siphon part and then go up to the HPOP and open that hose I bet the system will not push fuel up to the top of the HPOP location. Its the return line that is creating the flow as a secondary siphon.


Here is how I broke down the various choices in +/- when it came to sumps siphons surge tanks

Negatives:

* Cost
* Modifying OEM Dot Approved Fuel Tank ( cutting hole in bottom)
* Putting hoses and sump itself in a position that greatly increases exposure to getting damaged and dumping tank of fuel'
* Possible leaving one open to very large clean up bill if the above happens
* Does not creating any more flow or help fuel pump in any way over siphon

Positives:

* adds a small volume reserve as it becomes lowest point in fuel tank allowing sump port to stay fuel covered at very low tank fuel levels.


Siphon:

*Keeps OEM tank unmodified.

* Does not change fuel line routing or increase damage risk

* Has same head pressure and flow rate as sump

* Breaking siphon will stop fuel flow from damaged hose or fitting.

* Addition of a surge tank all other areas left (fuel pump location etc)

Negatives:

Has parts inside tank requiring dropping tank to work on should the need arise which is extremely low after typical 5/8 PU install.

Addition of surge tank to siphon system:


Positives:

Ensures constant fuel supply for pump in low fuel sloshing situations and or at extreme angles. ( more supply than sump).

Adds no increased exposure to fuel loss besides the addition of fittings.

Can be mounted anywhere along frame rail.

Not very costly

No tank modifications

Keeps factory style siphon fuel pu system

Various designs can allow for mounting actual pump inside surge tank thus allowing numerous other benefits or can stay as basic as a small metal or even poly tank inline pre fuel pump pre or post water sep filter.


Negatives:

Having to re route fuel line thru it.

Increases points of failure by adding more fittings.

 

[ju015dd]

Looks like a Strictly Diesel set up. I have one sitting in my garage just waiting to be installed.

correct! And love it! Was easy to install and works like a champ