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Fuel Crossover Mod

4K views 19 replies 6 participants last post by  imported_diesel71 
#1 ·
I've been following a thread that drifted into disscussion of this mod. I'm very interested in finding out more info on it. What are teh pros/cons of doing this mod. Can it be applied to the OBS trucks or is it just for the SuperDutys?

Is it a simple matter of connecting the fuel rails together in the same fashion as connecting the oil rails together or is it more involved than that? I thought I understood the mod in the other thread, but then I saw a diagram that showed a new aeromotive regulator and more lins being routed. I'm not quite sure I understand as I once had.

So lets here from everyone that's done it.
 
#3 ·
Hey big green here's the low-down...the Super Duty trucks have a dead head fuel system just like the oil system...why is another story...who knows the mind of Ford...:shrug:

The gist of it is to tie the two fuel rails together...the # 6 & 8 injectors get slightly starved for fuel due to their firing sequence and the air that is entrained in the fuel...hence the cackle or the ball peen hammer sound against iron, the noise it makes. By tying the two head together the fuel rail is always full since it acts like accumalator and air has a chance to be reduced by having this path (my speculation ok not necessarily right...LOL )

I will attempt to add more diagrams up if they are not to large to attach....oh the Aeromotive regulator is a mod to adj. the FP but since I have the FPR shimmed up already I don't care to spend the money on it....... I need a FTVB for the tranny.....he-he-he......

Any more I can confuse yah w/ drop a line.. er ah mean help...yeah...and no I have not gotten to it yet....have major living room project in progress....due to file limit I attached what I could that may help....

C-man
 

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#4 ·
more photos.....
 

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#6 ·
I'm not sure that you can just tie the fuel rails together. I know that Dennis at ITP has come up with the regulated return kit that does this, but maintains fuel pressure and returns the fuel from the heads to the tank. I have this kit sitting on my shelf at home waiting to install.


...on edit...are you talking tieing the fuel rails together, or the high oil pressure rails together. Tying the high pressure oil rails together is the HX mod, and ITP carries those as well.


Dave
 
#8 ·
4cstr said:
I'm not sure that you can just tie the fuel rails together. I know that Dennis at ITP has come up with the regulated return kit that does this, but maintains fuel pressure and returns the fuel from the heads to the tank. I have this kit sitting on my shelf at home waiting to install.


...on edit...are you talking tieing the fuel rails together, or the high oil pressure rails together. Tying the high pressure oil rails together is the HX mod, and ITP carries those as well.


Dave
I've already done the Hx..mod it's a great mod. No I'm am speaking of tying the #1 test port on the pass. side to the #8 port on the driver's side.

Texas Town Car did this mod w/ an accumalator and w/o one and had great success w/ it. It is the same principle as the Hx for the oil mod.

My plan is to get-r-dun after the living room project, to late to wean wife from HGTV...:roflmao: so I will report the results in about 3 weeks or so.......

The bottom line for is that the regulated fuel mod, by coming off the rear end of the heads by the firewall and tying to a Aeromotive regulator is more than I can presently afford, also why all that bother if another alternative is possible, I've got the FPR running at 68psi already so in theory it should be a simple mod, and a low cost one at that......my way of thinking outtah the box when budget is tight......

C-man
 
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#9 ·
Oh...icic. I remember that discussion many many years ago on a site far far away from here. LOL between TT and Hutch if I remember correctly. I thought Hutch and TT disagreed on the accumulator...but again memory is fuzzy.

I'll be the first to admit that I'm not all that well versed on our fuel system...but if you just tie the fuel rails together...without some sort of an escape route...how does that help? I mean...you have two fuel rails...and for argument sake have 60psi fuel going down each of them. If you have two streams at 60psi and simply tie them together...aren't you going to have issues where they meet? I guess thats why I thought Hutch went with the regulated return...the fuel runs from one fuel rail...to the other...then to the return line back to the tank.

But I would love to hear of your results.

Moose...just haven't had time to get it installed yet. Been busier than a 3-legged dog in a town full of fire hydrants.
 
#10 ·
4cstr said:
Oh...icic. I remember that discussion many many years ago on a site far far away from here. LOL between TT and Hutch if I remember correctly. I thought Hutch and TT disagreed on the accumulator...but again memory is fuzzy.

I'll be the first to admit that I'm not all that well versed on our fuel system...but if you just tie the fuel rails together...without some sort of an escape route...how does that help? I mean...you have two fuel rails...and for argument sake have 60psi fuel going down each of them. If you have two streams at 60psi and simply tie them together...aren't you going to have issues where they meet? I guess thats why I thought Hutch went with the regulated return...the fuel runs from one fuel rail...to the other...then to the return line back to the tank.

But I would love to hear of your results.

Moose...just haven't had time to get it installed yet. Been busier than a 3-legged dog in a town full of fire hydrants.
Yep, I see your point about the full flow return and am sure that it may be the best way to go. In theory from what I've read, the Fx line acts like accumalator and the #6/8 inj. will have full fuel fed from both ends and no dead head spot. But hey I'm a shade tree guy....TT used Bently-Nevada gear to get all the trace signals and I'm taking his word. Hey for a few bucks it can't hurt and will gladly post results..the good...and the bad....ugly is already driving....he--he...

C-man
 
#11 ·
I have done the fuel hx. it is simply tieing the fuel from one head to the other. this is not like the regulated return kit . I personaly like the regulated return better, it regulates the pressure after it comes out of the heads, the regulated return kit makes the fuel system a non dead headed system.:Thumbup: the fuel in the regulated kit goes threw the heads then to the regulator, from thier to the tank. putting a crossover line from head to head or (fuel hx) helps a littel bit with pressure spikes and fuel volume on the #6 & #8 injectors. the line acts like a accumalator and damper for the fuel. this all dependes on the size and length of line you use? yes this will work on a obs power stroke. :Thumbup: I have even tried this on a 6.0 and it made a huge differance. i had to remove it for heat and leakage problems, ill get back to that project when time is avalable?? :popcorn:
 
#12 ·
Thanks for the feedback diesel71...appreciate it.....no doubt the full system is the best but I've already shimmed the FPR to 68psi so the fuel Hx should help quiet it down even more.....I went to NAPA today and have the steel fittins on order and have 34" of 1/4" line, which is what TT used. The hose is rated to 400psi and is pushed on to a dual barbed fitting w/ a yellow end cap. So this coming friday Lord willing look forward to it......oh..sigh.....discovered TWO layers of floor tile over the carpet so ahem ...the living room project grows....it only takes 30 minutes on T.V. ... lol

C-man
 
#13 ·
I have no ideas about the Fuel System, But i also have been following along on this Mod, is it the same as the Hpop or is that the oil system? Oh Chinookman I started redoing my living room in February, it has turned into a whole house project, but thankfully i am doing the trim work now, just in time for my wedding Saturday.
 
#15 ·
barbershop said:
I have no ideas about the Fuel System, But i also have been following along on this Mod, is it the same as the Hpop or is that the oil system? Oh Chinookman I started redoing my living room in February, it has turned into a whole house project, but thankfully i am doing the trim work now, just in time for my wedding Saturday.

:roflmao: :roflmao: now its my turn......lol.....bought house 2 yrs ago and its 30 yrs old....:cry: so yeah.......I'm chomping at the bit can't wait to git the truck done...man oh man.......do these trucks affect yah'll like that too...I'm here sanding wood paneling ready to primer and mah head is thinking b.o.m for the truck and how to do the mod......man ah think I got it bad what ever it is....LOL :HappyMugs have a great week guys see yah'll later.....C-man
 
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#16 ·
barbershop said:
I have no ideas about the Fuel System, But i also have been following along on this Mod, is it the same as the Hpop or is that the oil system? Oh Chinookman I started redoing my living room in February, it has turned into a whole house project, but thankfully i am doing the trim work now, just in time for my wedding Saturday.
The HPOP system is big oil. By going with an aftermarket pump you can keep constant pressure to the injectors...keeping them from falling off. When I was on the dyno last weekend my hpop was ramping up nicely...but as soon as my chip called for more pressure, my hpop fell flat...went to 1200 psi and my hp and torque curves took a nose dive. Simply speaking.

Chinook...if possible...please take pictures of this as well. If this works out well I would be willing to work with you to write a tech web page article for the site.
 
#17 ·
Chinookman said:
:roflmao: :roflmao: now its my turn......lol.....bought house 2 yrs ago and its 30 yrs old....:cry: so yeah.......I'm chomping at the bit can't wait to git the truck done...man oh man.......do these trucks affect yah'll like that too...I'm here sanding wood paneling ready to primer and mah head is thinking b.o.m for the truck and how to do the mod......man ah think I got it bad what ever it is....LOL :HappyMugs have a great week guys see yah'll later.....C-man
I didn't sand my panelling, hope that doesn't haunt me, but if you are using a good oil based Kilz Primer you are in for a good time, just make sure the house is ventilated, i was :smoke: floatin when i finished mine LOL. And yeah my truck is doing the same thing to me but i have absolutely no money to put into it now, still wainting to get a tuner.
 
#19 ·
This thread has really taken off with some good info. :thanks: I'm trying to keep track of everything and learn the OBS fuel system as best as I can. There was mention of potential troubles by just tieing the two fuel rails together b/c of to much pressure where the two lines meet. I'm not all up on the nature of how liquid pressure works, but I don't think that tieing together two lines of a certain pressure, result in more pressure at the point of convergence. But I might be wrong. My wife says I'm wrong a lot.

Doing a little more brainstorming about this whole mod I remembered something. On the OBS trucks, isn't there a plug at the end of each fuel rail on the backside of the engine (next to the fire wall)? Couldn't we just tie together those to lines? It seams like this would make the system into a loop of sorts. I'm not positive of the direction of fuel flow, but in my simple mind it makes sence.

Does anyone have a flow diagram of the OBS fuel system?
 
#20 ·
I have a diagram of it. not sure how to post it yet. it wont result in more pressure, if you have say 50psi on one side and 50 on the other side, tieing the sides together will give you 50psi. now if you have 50psi on one side and 40psi on the other it will balance out the psi to a comman psi, like 45psi. thier are alot of varables on the comman psi, if it is not the same on both sides. thier is a plug on both heads you can use to tie together, on the left head its on the rear-on the right its up front. they are 1/8 pipe threades. fuel flow doesnt matter because its still dead headed.
 
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