Fuel Pressure Difference
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Lead Driver
Joined: Jun 2003
Posts: 8,298
Likes: 25
From: Damon (South East Texas)
Fuel Pressure Difference
Has anyone checked their fuel pressure prior to and after installing the Cackle Cure Kit? I was wondering if there was a slight drop in pressure due to the bleed orifice in the fitting before the fuel return line and if you adjusted the pressure to compensate for this drop. I have my pressure shimmed to 65 psi.
Freshman User
Joined: May 2003
Posts: 45
Likes: 0
From: Alabama
Didn't check it before, didn't have gauge then, it would be very interesting to know if there is a difference. I have mine shimmed to 65 and thinking about trying to go a little higher. When I first shimmed mine it was 68 now it's 65. Just wondering if the spring is collapsing.
Hotshot
Joined: Nov 2006
Posts: 11,286
Likes: 263
From: North of Greenville
Don't have a gauge, but I doubt if there is much difference. The orifice in the cross-connect tee fitting is not much more than a couple of thousandths, IIRC. I bet Jason (FN74) has that information handy.
Elder User
Joined: Oct 2006
Posts: 635
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From: New York
Nope, there shouldn't be a pressure drop. The orifice is only .020. At least not unless it is installed wrong- with the orifice pointed to one of the heads, instead of the return line. Believe it or not, Factory spec for fuel pressure is only 51 psi, but we all know better than that. One of the reason for increasing fuel pressure is to help provide better fuel flow to the #8 injector, which this kit resolves. I have not dyno'd it, but I would be willing to bet that there would be no differance in power after a CCK install between 60 psi and 70 psi. So with that said, allow me to be hypocritical
and say that my personal fuel system is set at 80 psi. As are all my DPP (FASS) pumps that I sell for the PSD.
The point I was trying to make though is that with a stock or mildly chipped truck, you are not likely to see any benefit from doing the CCK and shimming of the Fuel pressure so long as it is above 60.
and say that my personal fuel system is set at 80 psi. As are all my DPP (FASS) pumps that I sell for the PSD. The point I was trying to make though is that with a stock or mildly chipped truck, you are not likely to see any benefit from doing the CCK and shimming of the Fuel pressure so long as it is above 60.
Elder User
Joined: Oct 2006
Posts: 635
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From: New York
Originally Posted by SBChero
i saw a slight drop when i first installed the cck. about 3 or 4 psi. but this could just be the difference in the crappy gauge that i have.
Fleet Owner
Joined: Jun 2004
Posts: 25,090
Likes: 1,112
From: Rio Rico, AZ.
I agree, there will be no pressure drop if everything is ok. The fuel pump will make up the extra fuel volume that is bled off through the oriface until it starts to open the fuel pressure regulator. Since it's such a tiny hole, it's a non-issue.
