Modded cp3 questions

dmaxbowtie

dmaxbowtie

Duramax fiend
Jun 2, 2011
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I had a spare cp3 on the shelf and read some DIY cp3 mods, I'm just looking to get a little more rail pressure, so im going to enlarge the inlet and outlet on the gear pump and enlarge the high pressure fitting. I am also going to modify the lb7 fpr to even though I am running an lbz fpr currently. My main question is this: in the "instructions" it says that my inlet and outlet on gear pump should be .110" and to open them to .140"-.160" but the inlet and outlet are already over .150", the instructions were for a cummins cp3. Should I leave them alone or open it up? What should the size of the gear pump inlet and outlet be on a stock lb7 pump? I should also add that I'm sending the pump to industrial injection to be tested after I'm done.
 
PAT

PAT

EASY DAY
Aug 21, 2011
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I've measured. Measured <400 psi rail after 2k miles. Got an extra pump? Want more rail? Buy a dual fueler kit. Or build your own and buy the controller. Modded pumps are like hookers. You don't know if their gonna blow your mind, or leave you broke and on a street corner.
 
dmaxbowtie

dmaxbowtie

Duramax fiend
Jun 2, 2011
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And it says 85% ii modded cp3 in your sig ;p. I know your right pat, but in your opinion what would fail on a modded fpr/suction pump?
 
PAT

PAT

EASY DAY
Aug 21, 2011
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Yes it says 85% ii in my sig... HOWEVER. It failed a while back. With less than 2k on her. Immediately after install, the pump held a best of 19.5k psi. Never made full rail.

I don't think that a modded FPR is a bad idea. But I think a modded pump is. Just run an LMM pump with an modded FPR.
 
dmaxbowtie

dmaxbowtie

Duramax fiend
Jun 2, 2011
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That's going to be my plan( to just modify the fpr) and possibly open up the high pressure fitting. Thanks for the input pat.. See you at the east coast nationals in pa?
 
PAT

PAT

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Aug 21, 2011
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Nope. Getting rid of the truck. The plan is to build a turbo RC/SB 1500. Should be a light little runner. Id low to go just to watch the races though.
 
juddski88

juddski88

Freedom Diesel
Jul 1, 2008
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I would highly recommend NOT sending the pump to II. I would just run a lbz/lmm pump and be done. If you want a modded pump, then call exergy and open your checkbook.
 
PAT

PAT

EASY DAY
Aug 21, 2011
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juddski88 said:
I would highly recommend NOT sending the pump to II. I would just run a lbz/lmm pump and be done. If you want a modded pump, then call exergy and open your checkbook.
Click to expand...

x's 2.

also, with a modded FPR, tuning can be a little tricky. do you understand how the internals of an FPR works?
 
PAT

PAT

EASY DAY
Aug 21, 2011
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juddski88 said:
I would highly recommend NOT sending the pump to II. I would just run a lbz/lmm pump and be done. If you want a modded pump, then call exergy and open your checkbook.
Click to expand...


i would feel ashamed to be the owener of II and have replies like this about my products.
 
dmaxbowtie

dmaxbowtie

Duramax fiend
Jun 2, 2011
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I was going to have them flow test the pump after I modified it, and even check the condition of the pump, I have enough understanding of the fpr to be dangerous ;) and you honestly don't think industrial injection could flow test it for me? I'll send it to whichever place is going to do their best to make sure it's not going to wipe out all of my injectors
 
dmaxbowtie

dmaxbowtie

Duramax fiend
Jun 2, 2011
228
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The whole reason I'm doing this is because I want to achieve over 550 whp I really want 575(I know dyno numbers mean nothing) so anything 12.40 or faster will satisfy me, I last dynoed 525 whp and I don't know what 1/4 mile times to expect at that power level.. I'm going to install caltracs this week and I'm eyeballing some rancho shocks... But I have a stock shortblock at the moment which is why i was going to mod the fpr on the cheap in hopes for a little more rail pressure up top, dual cp3s are too much at this time and certainly two new lbz pumps and a kit :/
 
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