043500QC

I`m pretty sure its 1/4", but I`m not gonna swear thats what it is.

Geico266

The return line measures .312 OD, that = 5/16 outside diameter, not the diameter of the hole. If the wall thickness is 1/32 then it is 1/4" ID.

Superduty

"It's part of the banjo bolt where the return line leaves the VP."

It is referring to the relief valve on the VP44.

Could someone pull this from their VP44 and post some pictures of it.

It would be really neat to mod that valve and have all the fuel go through the VP44 at a reasonable pressure and not have any bypass plumbing at all.

I was thinking of doing the same thing with the cascade overflow valve on the CP3, but the internal pump pressures in a CP3 are used to control fuel delivery with the FCA, so I decided not to touch it.

On the VP44 fuel delivery is controlled by plunger stroke, so modding that valve is probably a thing that could be done.

If the pictures look reasonable, maybe I will buy one and have a closer look at modding them.

In the mean time, fuel flows and testing the 1/2" Swagelok seem worthwhile activities, to me anyway.

Does anyone see a problem with pushing 80 GPH through the VP44 at 15ish PSI ?

I think it would be well lubed and well cooled !

slim51015

Whats the psi. if you remove the Swagelok valve all together? Just run a bypass.

043500QC

Don`t know, we thought about trying that also, but kinda backed out of doing it in fear of over pressuring the fuel filter lid/canister.

043500QC

Which line is that, the metal, or plastic one ? I`m not arguing, just curious as to which one you`re referring too.

Geico266

The metal line on the inside frame rail. The supply line is 3/8" OD.

slim51015

I think you misunderstood my question. What if you removed the swagelok and just run a bypass like superduty did. What psi would you see?

Superduty

"Don`t know, we thought about trying that also, but kinda backed out of doing it in fear of over pressuring the fuel filter lid/canister."

I think he meant just put a line between the VP44 inlet and the return line and feed the VP44 with a few PSI. With no regulator at all. Like I am doing with the CP3.

Conversely, why not just remove the bypass altogether and disassemble or remove the VP44 relief valve and then run all the Walbro fuel through the VP44 at whatever pressure it generates. It will be well cooled and well lubed. I can't see it starving with 80-85 GPH running right through it.

Would the fuel run through the VP44 if it wasn't turning ?

I suspect the VP44 relief valve is designed to keep fuel in the pump rather than draining out the return line in the case of there not being enough fuel going to it.

You might also be able to get rid of the bypass, remove the VP44 relief valve and just put the 1/2" Swagelok in the return line right after the VP44. Essentially that would replace the stock VP44 relief valve with the 1/2 Swagelok doing the same function. It should have enough flow capacity to keep the pressure in the VP44 right where you set it, plus you'll have 80 GPH going through the VP44.

I really like this idea.

Superduty

"What psi would you see?"

I think he would see 4 PSI at WOT, a bit more at idle. I don't know if I like that because it doesn't force fuel through the VP44. The idea is to get fuel moving through the VP44 so it gets lubed and cooled. On the CP3, its lift pump makes sure that happens. On the VP44 the Walbro has to push fuel through the pump and there needs to be a pressure differential between inlet and return line for that to happen.

I'd be more inclined to remove the bypass, remove the VP44 relief and push all the Walbro fuel through the VP44.

But it is YOUR truck, not mine.

043500QC

How would you regulate the pressure to the VP from the Walbro pump ? Don`t you need some kind of regulation so that ya don`t crack the lid or canister ? I thought that was the hole point of the regulator in the first place???

Don`t really want to get into removing the VP`s relief valve if we don`t have to. The whole point of doing all this is to save the VP, not sure my dad is gonna want to experiment that far with this.

Dunno, you to tell me, lol.

I`ll agree with that, makes perfect sense. It creates just enough back pressure to hold fuel in the pump.

Again, I`m not sure dad wants to get this far into the system being that no one seems to be quite sure of the exact purpose of the relief valve on the VP. This VP isn`t a cheap part, and if it were me, I wouldn`t fool around with it that much. I do, however, like the idea, but don`t think I would want to be the giuena pig for everyone else.

Hey dad, jump in here anytime.

Superduty

I totally understand your position about not wanting to experiment on your VP. No pressure from me to anything you don't want to do.

If you think about it, the stock VP flows all the fuel that the stock lift pump gives it. Removing the stock VP relief valve and using the Walbro would be doing the same thing. Except it would be fed by a firehose instead of a straw.

Sea01Cummer

I'll have to say that i am impressed with the cooperation and the imput from people trying to figure this out. I have the exact same issues with the holley regulator that he is having with the swagelock. I think the pump is over powering the regulatoe and dumping all the fuel to return. I am in the middle of home remodel stuff and my truck tinker time is limited. I too have wondered what would happen if you ran the pump with no regulator, i'm a bit scared to try i'll admit. Let's try like hell to get this figured out , there are tons of people who can benefit from the outcome. Thanks to all that are helping.

Stevo

Geico266

I'm not trying to start a war, rain on anyone's parade, continue a battle, or give the mods a headacke, but, I think at this point someone has to ask, is the Walbro the right pump for this application? Seems to me there should be a pump that has the ability to regulate the flow / PSI to what the application needs and more importantly what it was designed for.

I have gotten 185K miles on my original VP-44 by CAREFULLY monitoring fuel pressure of the stock set up.

BTW SD good luck with the baby.

Superduty

Before I would run the bypass without the regulator, I would remove the VP44 regulator and run all the fuel through it. The idea is to move the fuel THROUGH the VP44. (Capitals were emphasis, not shouting...) I don't think the VP44 will suck fuel like the CP3 will.

It is great to be working with people instead of fighting against them.

Isn't it ironic that we are fighting too much pressure versus not enough of it ?