Sea01Cummer

I have underhood gauge hooked in to the shreader valve on the side of the injection pump. I plan to put one in the cab i just haven't done it yet.

Steve

Sea01Cummer

The holley reg has 2 out ports and one in ports so would i put it after the vp in the return line and plug one of the out ports? This reg does not have a return port like i thought.

Steve

Superduty

I don't think a 2 port regulator will work.

Such a regulator will regulate the fuel pressure downstream of the regulator, but it won't spill the excess fuel to the return line. You need a regulator that will spill excess fuel.

I think you need a 3 port regulator like a 12-803BP.

If it was a returning regulator, you would plumb it like figure 2a in this diagram, putting the injection pump where they have the carburetor.

http://www.holley.com/data/Products/...199R7914-3.pdf

Sea01Cummer

I ordered the regulator you mentioned above and it will be here tomorrow. Looks like i will be set for the weekend.

Steve

Superduty

<chuckle> Is your Dodge going to have any allergic reactions to having a Ferd part on it ?

Berak

Supertduty, your links to those swagelock regulators gets mangled by their website. Do you have that part numbers handy?

Does the stock filter mounted pump push fuel through the filter or pull it through? I'm thinking for ease of replacement, coming up with something that replaces the stock unit with as little else changed as possible would be great. The extra 10 ft. of pushing versus pulling shouldn't be a big deal for a pump that's over engineered for it's utlilization.

Anyone have part numbers or prices for the Dodge parts for bypassing the factory filter mounted pump?

I probably won't do anything till my stock unit dies but I'd like to be prepared.

Superduty

B-4CPA2-DG-3

Description: Brass 1-Piece Poppet Check Valve, Adjustable Pressure,1/4 in. MNPT, 3 to 50 psig (0.21 to 3.5 bar), Green Deflector Cap

It looks exactly like a longish 1/4" hex nipple, if you know what that is, but inside it is an adjustable pressure relief.

It is the fitting in the lower right hand corner of the cover of this catalog:

http://www.swagelok.com/downloads/we.../MS-01-176.PDF


"Does the stock filter mounted pump push fuel through the filter or pull it through?"

Push.

"I'm thinking for ease of replacement, coming up with something that replaces the stock unit with as little else changed as possible would be great."

IMHO the stock filter is OK, but it could be finer. I'll be putting a CAT 2 micron filter between the stock and the CP3 on my truck.

"The extra 10 ft. of pushing versus pulling shouldn't be a big deal for a pump that's over engineered for it's utlilization."

It is not a problem as far as the pump is concerned, but you have to watch how much vacuum it takes to move the fuel as well as how fast the fuel moves in the lines or you will get flashing.

Sea01Cummer

I will force feed the old girl the ferd part, i could care less as long as my VP lives 83k on original ( yes i am nervous). Thanks again for answering my questions and i will post the results for others to draw their own conclusions.

Stevo

Berak

Thanks for the information. I just figure since my stock lift pump is doing OK at 50,000 miles from that spot, a better pump shouldn't have any problem.

How do I "watch how much vacuum it takes"? What is flashing (igniting?) and why is either of these things more of a concern with this pump in the stock location?

Nascarcamper

Here's where I just bought mine: http://cgi.ebay.com/ws/eBayISAPI.dll...e=STRK:MEWA:IT
Now just need the piece to replace the stock lift pump. Found out I went to high school with this guy, BIG time Buick GN guy, now that I have two of them, I think I will be talking more to him.

Superduty

Hey, you bought a Walbro for $110. Good for you. And that is with the mount kit. Thanks for believing enough to give it a try !

<It looks like they are using those pumps on the Buick GN cars.>

It isn't a totally safe assumption that a new pump would be safe from that location with the stock lines. The short answer is, yes you will probably be OK. Here is the long answer.

Flashing is when a liquid starts to go to a gas or what is called a vapor. If you take a hydrocarbon at say room temperature and start reducing the pressure (putting it under a vacuum) some of the liquid will turn to vapor. Not a big deal with diesel, because it takes quite a bit of vacuum to get to a lot of vapor. But if you lower the pressure enough, it becomes a big deal. FWIW, gasoline flashes easier than diesel.

Now... how do I explain this... the pressure on a liquid in motion is the sum of two different components. Its pressure due to its velocity and its static pressure. The greater the liquids velocity, the greater its velocity pressure.

The pressure we read on a gauge is really the total pressure of the liquid. It helps to think of the these things in terms of absolute pressure to make it less confusing. So when our gauge reads 0 PSI, we have an absolute pressure of 14.7 PSI, etc.

So lets say that the total pressure on the suction side of the pump is 10 PSI absolute or 10 PSIA. (A vacuum of 4.7 PSI) Now if the fuel is at a standstill when we take this pressure the velocity component of this pressure is 0 PSI and the static pressure on the fuel is 10 PSIa. (10 -0 = 10) And we probably don't have a flashing issue.

Now lets say we are moving the fuel really, really fast through a small line with a total pressure of 10 PSIA. Because it is moving really fast, the velocity component of the total pressure might be 8 PSI, leaving us with a static pressure of only 2 PSIa. (10-8 = 2). This would cause a problem. The diesel would turn to gaseous diesel and our pumping element isn't air tight, only liquid tight and we have problems. People call this vapor locked. The pump housing fills with vapor, the pump doesn't pump vapor and we have a problem. It also occurs in lesser forms where he pump doesn't stop pumping entirely but the pumps performance is affected.

So you have to make sure that the inlet line is big enough that the fuel doesn't turn to vapor due to a low static pressure.

One more thing. Sometimes people make a big deal out of whether the pump is above or below the tank. Water has a pressure of 0.46 PSI per foot of elevation. Diesel fuel is about 0.37 PSI per foot. So the difference of 2 feet isn't USUALLY a big deal, but then sometimes when dealing with a vapor situation every PSI is critical.

I neglected to include the pressure loss from the drag of the small fuel line in the above discussion. Going to a larger diameter line on the suction side is a double good as far as vapor lock goes. First it reduces the fuel's velocity pressure. Secondly it reduces the pressure drop due to the line itself. Just so you know.

As long as you aren't putting a big honking pump on, you should be fine.

trik396

Hey SD,
My Walbro is on the way. I've been talking to the people at Swagelok. Either they are confusing me or I'm confusing them. Regarding the part number you referenced: If installed on the bypass that you've shown on your setup, it will keep what ever pressure (3-50psi, my choice) on the cp3 feed side and release excess to the return. Correct?
Sorry for what I'm sure is a redundant and somewhat stupid question, but I've had a hectic week to say the least.
Thanks
btw- looks like that part can be had for $22 and some change. Much less expensive than a normal "regulator".

Superduty

"My Walbro is on the way. "

Good stuff.

"I've been talking to the people at Swagelok. Either they are confusing me or I'm confusing them. Regarding the part number you referenced: If installed on the bypass that you've shown on your setup, it will keep what ever pressure (3-50psi, my choice) on the cp3 feed side and release excess to the return. Correct?"

Yes it will. But not the way a 3 port regulator from Holley does. The Swagelock part is a relief valve. It is just 2 ports, one in and one out. Whenever the pressure reaches the set point it opens and whenever it falls below it closes. It is very good at maintaining pressure at a setpoint in a system.

Look at the catalog link I put in. It has a picture of it. You should be able to figure it out from that.

So... with a typical Holley setup, you have three ports (in, out and return) and you install it like this:

in - connects to the line from the filter assembly
out - this is the controlled pressure port. You connect this to the injection pump
return - you tee this into the return line, together with the injection pumps return

Now the Swagelok system is different. It goes right into the bypass line. That system is plumbed this this:

fuel filter outlet goes to pump inlet
pump outlet goes to return line
(both of these are as they are right now on your stock truck)
bypass line goes from pump inlet to pump outlet
(Swagelock pressure relief fitting goes in the bypass line)

So when using the Swagelock pressure relief fitting, your bypass line will look just like mine, except that it will have that 1/4" hex fitting in it somewhere. And you might use something other than a plastic fuel line.

Does that make sense ? It isn't the traditional 3 port regulator, but it does the same thing. The Holley is a the same as a Swagelok with a T on it.

I like the Swagelock because it is high performance, inexpensive and small. However, it isn't nice to adjust. But you should only have to adjust it once and it will be good forever.

By the way... you have to install the Swagelok relief valve in the right direction. It has arrows on it to indicate the flow direction.


"btw- looks like that part can be had for $22 and some change. Much less expensive than a normal "regulator"."

I am surprised they are that much. But I havent bought one in a couple years.

Berak

Thanks for the flashing explanation, it was something I never would have considered to a potential problem. In your description however I see no mention of the distance between the pump and fuel pick up. Is flashing an issue with this pump near the tank using the stock lines? I'm going to go out on a limb and just believe that with this pump using factory lines, we can safely ignore flashing as a potential problem. It isn't pumping nearly as much as a FASS unit for example.

So trik396, what's everyone doing for the stock filter mount bypass?

Superduty

No problem.

The distance plays into the system by dropping the pressure more with longer lines.

OK... when one is sucking fuel form the tank what is really happening is that the fuel pump is reducing the pressure of the fuel at its inlet and are (at 14.7PSI) is pushing the fuel.

So... Lets say that we are pumping our fuel with a 3 foot suction line and our velocity pressure is 3 PSI and the absolute pressure at the lift pump is 13 PSIa. We have 14.7 PSI at the fuel tank pushing on the fuel, so that means the line restriction must have been 14.7 PSI - 13 PSI = 1.7 PSI. No big deal. Our static pressure at the pump is 13 PSIa - 3 PSI = 10 PSIa. That is probably about as low as we want to go.

OK... lets change the system so we have a 15 foot suction line. Our pressure drop due to the line is now 15/3 x 1.7 = 8.5 PSI. **IF** we assume the fuel still moves at the same velocity, our static pressure drops. We have 14.7 PSI at the tank. We have 8.5 PSI pressure loss on the line. Our total pressure at the pump inlet is now about 14.7 - 8.5 = 6.2 PSIa. We still have 3 PSI of velocity pressure. Our static pressure at the pump inlet is now 6.2 - 3 = 3.2 PSI. We have have problems because at this pressure the fuel will be vaporizing.

Now, I made an assumption in the calculations that the fuel was still moving at the same velocity. If the pump is drawing vapor, it has probably slowed down. And this affects pump performance.

"In your description however I see no mention of the distance between the pump and fuel pick up. Is flashing an issue with this pump near the tank using the stock lines?"

Probably not.

"I'm going to go out on a limb and just believe that with this pump using factory lines, we can safely ignore flashing as a potential problem. It isn't pumping nearly as much as a FASS unit for example."

I agree it is safe to try. You will know if you watch and time the flow from the return line if you are getting good flow or not. It would be great if someone set one of these systems up, set the regulator pressure at the injection pump to 15 PSI and then cracked the return line somewhere and measured the return flow. It should be in the 70ish GPH with the Walbro.

Yeah, still WAY more than the engine needs. You guess would have killed yourselves laughing at me if I told you to try a 40GPH pump. But that is really all it takes for a stock engine. 40 GPH with a rated pressure of 40-50 PSI, would be OK. The big Walbro rated at 80 PSI, will provide just that much more safety margin. And for $110, it is pretty hard to beat price wise.