fuel line going to the back of the driver's side head? I must not be thinking on the same page as you because none of that makes sense?

 

It's going to need someone that understands hydraulics better than me to answer that one. But since the pulse is traveling through a liquid that can not be compressed, I would think it's going to go until it hits some kind of restriction, no matter how far.

 

I'm just saying I agree there is a huge amount of vibration from the injectors. Just grab the fuel line that you connected to the back driver side fuel port. That sucker really transmits the vibration. That's all....

 

My return line that is attached to the .008 orifice hardly vibrates at all. And it is only seperated by the brass T and orifice. I noticed it enough to also get rid of the zip-tie holding the return line and back passenger side line together.

 

Not sure of exactly what your saying here. Does this mean you are only getting the pulsations from the fuel inlet to the rails and not the outlet? Both sides?

 

Nope, just the outlets that don't have the restrictors. I'm sorry, I'm not putting this to words very well. My OEM feed lines are in place....

 

Very interesting..... OK Jason, jump in here and help explain all this.....

 

Here's what I'm gathering.

Hydraulic pressure will take the path of least resistance.
With OEM plugs in place, the restrictors take the brunt of the spikes.
With the plugs removed, the pressure will release itself downstream to its first obstacle, once it has overcome pressure loss due to line friction and any potential line expansion (as in a rubber fuel line).

The Kwik and Cackle systems allow these spikes to be transferred over to the opposite head through the crossover line, and the spikes from each head are "tempered" through an orifice that is restricting flow back to the fuel return line.

The reg fuel system is letting the regulator take these spikes (unless there is a built in orifice to buffer such spikes).

If the restrictors are moved to the exit ports, there is nothing to prevent these spikes from "back feeding" into the HPOP between pump strokes, which violates their original design intent and may have a negative impact on the HPOP.

Here is what seems to be the ideal appraoch to me, given the above.

For a reg fuel system, leave the inlet restrictors where they are and consider inserting a moderate (not tiny) orifice ahead of the regulator to buffer the pressure spikes it sees (again, unless the regulator already has one built into it's design).

For a Cackle system, leave the inlet restrictors in place, use hard lines between the exit ports, and keep a "sacrificial" rubber line on the orifice tee discharge that goes to the return line, and make this "sacrificial" hose long enough to absorb vibrations and provide ample surface area for a slight stretching with the spikes... This will keep the highest pressure available to the fuel rails and at the same time cushion some of the spiking that will go through the orifice tee to the return line.


JASON... what's your spin on this?

 

Okay, no need to worry if restrictors are removed. Don't believe I have read about anyone's engine or fuel pump failing after removing those. And the 94-97 trucks don't come with any. I just wanted to establish their function and performance. The shock waves will travel in all directions that are unrestricted. And Fluid will transmit sound waves or compression waves until blocked or the the energy is absorbed by another object. Like a ripple in a pond from a thrown rock. In fact, the Indian Ocean Tsunami would be a great lesson on the effects of energy travel through a fluid medium. On a traditional regulated return, the the snubbers are removed and new lines are installed from the fuel bowl to the ends of the fuel rail, then the other end is tied to the Regulator, then back to the tank. And the Return on the fuel bowl is capped off. And I got off on a tangent. More stuff on the regulated return later.

When the snubbers are removed, it allows those pressure spikes to make it all then way back to the pump where it plays hell on the pump. These spikes are not necessarily strong enough to damage the fuel bowl, or cause any damage to the regulator, which is only a spring and washer basically.

Back in the beginning I used an Aeromotive pump with the very early version of the Vegistroke where I used a common manifold and then went through the stock fuel lines and snubbers, the fuel rails, a regulator and then back to the WVO tank. Anyway, I used the Aeromotive successfully for nearly a year. No trouble at all. I revised my system, hooked up the Aeromotive to the opposite fuel ports without the snubbers, and the Aeromotive broke within two days. And about 5 others out there on other customer rigs. All in all went through about 10 Aeromotive pumps. Only here recently did I realize the reason for that. Because of the pressure spikes from the injectors. The Aero's use a composite vane in the pump that is extremely hard and high in tensile strength, but also very brittle. Those spikes would break that vane everytime. Talk with a few of the big name diesel shops and they will tell you that they started with the Aeromotives on the regulated return but kept breaking. And that they are junk. I went round and round with one place over the cause of the breakage of those pumps. But hey, I'm just a grease guy.

Again I have not seen any real correlation to removing the snubbers and failing stock pumps. Some aftermarket pumps, such as the Fass have steel gears and appear unaffected by these shockwaves. On the cackle cure stuff mine or your own, the tiny orifice will basically block the shockwave from the return side.

In my personal opnion they should be left alone unless you are building an all out 600hp PSD. However if the deed is done, and there is no problem, I don'see where it is a high priority to go out and put them back in- Kwik

Oh, and Pete- Nothing in the fuel system will have any effect on the HPOP system.

 

HPOP? Who said anything about an HPOP being tied to the fuel system?? Only an IDIOT would make that kind of comment!!

DUHHHH!! Seriosuly, though....I don't know where I came up with that HPOP comment. I know that it isn't connected... I just don't know how that entered my mind. Serious brain fart there. Thanks for the correction!!

 

How about using a check valve at the stock feed to the head, and then the orifice tee'd into the crossover line? Would check valves close quick enough to keep the pulses from getting back to the pump?

 

Thanks for that info Jason. I have been contemplating fuel system changes for over a year now and this just adds more food for thought.

 

I keep reading and soaking it in. Keep talking guys, its very interesting. There has been so much discussion on this here and the other site, I just wish it was in print and not on my computer because it sure would be nice to contemplate all this while in the ultimate place of contemplation, or is that constipation, lol. I only know this..... The in tank mods and the cackle cure have made dramatic differences in my trucks initial start up, idle and low RPM smoothness and quietness and the overall smile on my face whenever I turn the key knowing I have done some good things to the longevity of my freedom mobile. I listen to every PSD that comes within ear contact and I can honestly say the only ones I have heard that come close to the quietness and smoothness of mine is the 6.0 and I only wait for the mod that will get me to that sound. Happy Friday!!