Lb7 fuel rail info

JOHNBOY

< Rocking the Big Single!
Aug 30, 2006
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0.027 is possible all i had was .025 and 0.030 to measure with John
both lines as you have shown in the pic go to the rail from the distribution block
the return is also from that block but does not as far as i can tell come from the block, And as far as i can tell it comes from the return from the cp3 unless over pressured on a lb7( this will be removed on my truck);)



yes its the D block but the FRPRV is inbetween the banjo and D block
the return line from the cp3 is inline with the banjo and from what i can tell AND comes from the CP3 NOT the rail.....I might be wrong? but im pretty sure:)

I had to look in my notes. I measued them with gages pins at work.




Your pic and caption cunfused me.:dontknow: That is why I posted the pic with labels.:D
 

sweetdiesel

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Aug 6, 2006
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I had to look in my notes. I measued them with gages pins at work.




Your pic and caption cunfused me.:dontknow: That is why I posted the pic with labels.:D


John I tend to do that sorry:baby:


I measured with a set that i bought a local parts store and i cheaped out:angel: It might have been Nappa:D
 

sweetdiesel

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Aug 6, 2006
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It comes directly off the CP3 and goes to the tank. That valve is a high pressure blow off if I am not mistaken.

Who needs those?:D



Thanks, That is exactly what i was thinking


One thing i find strange is they use low pressure lines on the relief
it must be because the low volume,but WOW ive seen some POP valves at work go and it gets ugly 0-190 mpa in a MS:eek: you want to see line bucking....but its all due to volume i geuss
 

LB7Diesel

Oh Boy!
Sep 3, 2006
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So basicaly your making it just like a lly with a drilled fitting? I also wonder why the lb7 fuel rail inlet is opposite the lly. Also does the lly have a fitting that has to be drilled on their pass side too?
 

sweetdiesel

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Aug 6, 2006
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So basicaly your making it just like a lly with a drilled fitting? I also wonder why the lb7 fuel rail inlet is opposite the lly. Also does the lly have a fitting that has to be drilled on their pass side too?


who knows what or why GM did what they did?

If we drill out the orfice on a lb7 and drilled the fitting on the LLY they would be the same as long as we drilled with the same bit

removeing the orfice will be a little bigger and would now have the ID of the actual rail fitting being the biggest restriction

I dont know what the ID of a stock lly is but have seen the pics and it also looks small
Larry swapped his out on his lilly....maybe he can throw in some knowlege

I think Pat did on casper and never noticed any gains also
 

mvnvltn

Part's Limit Tester
Aug 22, 2007
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If we open the rail up larger than the fuel block wouldn't that be a waste?

Tapering down builds pressure, not tapering up. Right?
 

sweetdiesel

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Aug 6, 2006
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Makes perfect sence Simon, Good info. Do we feel theres any gains inside the distribution block also?


Well yes and no,I myself do not know if getting the Industrial injection hose is worth the money or not? if you look at the instuctions they remove the pop valve and run a line in there off the extra outlet on a stock CP3

I dont think drilling or boring out the block is going to help unless you actually change all fuel lines and fittings
 

LBZ

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Jul 2, 2007
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Well yes and no,I myself do not know if getting the Industrial injection hose is worth the money or not? if you look at the instuctions they remove the pop valve and run a line in there off the extra outlet on a stock CP3

I dont think drilling or boring out the block is going to help unless you actually change all fuel lines and fittings

Which I don't think you wanna do unless you are running 2 CP3's for sure. That's a lot of volume required to maintain pressure. Plus you would have to change all the lines to the injectors as well.
 

LB7Diesel

Oh Boy!
Sep 3, 2006
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I don't think removing the orifices completely will show gains unless the volume from the pump can keep up.

Wouldn't removing the orifice and using the fittings ID as the restriction be about the same as the lly fitting mod? Both cp3's are about the same. So I would think you would then have basically a lly fuel rail.. Just wondering here.:D
 

sweetdiesel

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Aug 6, 2006
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I dont think we can completely remove the orfice, what i didnt realize untill today is that the rail fitting goes all the way into the rail now ( not good ) as you will be altering the lenght of the fuel line and this sounds like a disasster waiting to happen

Im now going to simply drill out the orfice