Fuel Line Question

bigmackmiller

Active member
Nov 30, 2008
1,046
2
38
Kokomo, IN
At what point horsepower or fuel demand (10mm & 65% SAC) do I need to look at increasing the supply lines to the CP3? I am getting ready to install my 369 and was wondering if there was anything else I should be addressing while I was in there? I installed all new factory lines when I installed the pump, but I don't want to hit a restriction if I push on it.
 

DAVe3283

Heavy & Slow
Sep 3, 2009
3,727
296
83
Boise, ID, USA
I'm on a 12mm CP3 and 75% SAC injectors with a S371 and have no issues with the stock supply lines, at least along the frame. Once they hit the motor it goes straight into the CP3, but that is because the factory routing was stupid and annoying.

I bet you can push 700+ HP through the complete factory fuel line setup if you run a good lift pump. I think you'll be fine with the parts you listed.
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
4,165
1,274
113
Larsen, Wisconsin
My truck is a little different (LLY) and ran into FICM restriction at the ~800hp mark coupled with a weak AirDog 2 165 not being able to hold pressure feeding a 14mm. Personally as long as you're running a good lift pump I think you should be fine. As you get larger in terms of pump stroke they exponentially like lift pump pressure at higher demanded flow rates (IE my 14mm loves being fed by 50psi at WOT) as they seem to have a harder time getting fuel into themselves. The 10mm doesn't suffer from this condition to anywhere near the extent of a 14mm.


Long story short, keep a good lift pump on it and you'll be fine. A larger feed line going into the CP3 isn't an awful idea but I wouldn't call it a requirement. The inlet fitting is the restriction in terms of the thread size going into the pump itself.
 

bigmackmiller

Active member
Nov 30, 2008
1,046
2
38
Kokomo, IN
Yea I have a 165 also on there, sounds like I’ll have stock motor limitations more than I will fuel restrictions, might look into a different inlet fitting


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