quick fuel pressure question

[BlackVert]

what is the stock pressure at the rail with the vacuum on again?

my injectors were flow tested for 30.1 lbs/hr at 43.5 psi but i know that our pressure is lower than that. i need to lower that number for my tune.

i should know this, but my memory has gone to hell. i did a search but did not see the answer in the first 10 threads of the results

i'm sure you guys know this off the top of your head ... :SNSign:

 

[HISSIN50]

It will vary. Anything above 30 PSI is acceptable though most folks are in the 32-34 PSI range at idle with a stock-ish vacuum signal.

 

[BlackVert]

what i actually need is the number ford expects it to be with the vacuum off. since i am doing math with it to determine my injector flow rate, a difference of 1 psi makes a difference in the tune.

30.1*(39/43.5) = 26.98
30.1*(40/43.5) = 27.68

 

[HISSIN50]

I see what you mean. I believe I have the spec for a fox III but not CBAZA. Bump for you.

 

[grngt50]

i believe it's 32 with the vacuum hooked up, and around 39 without

 

[Grn92LX]

39-40 psi no vacuum. With vacuum, it will vary depending on the camshaft. Camshafts that produce less vacuum will result in higher pressure at idle.