Im using the utility to calculate my BPC vs. VAC and I had a question on it.

On the left side it says fuel pressure. so Obviously I put my fuel pressure there that I am running. Below that is asks for injector flow rate. Do I put what the injector flows at 13 psi? 15 psi? or what I am running it at? and if it's where I am running it at. How do I determine what is it? I have holley TBI with 65 lb injectors at holley rated 14.5 psi I believe.

I dont want you to do the math for me. I wanna see where the equation is so I can do it. Let me know please. Thanks!

 

For TBI it is the flow rate at 13 psi (see the help in the utility).

With a flow rated at a different pressure, need to play with the utility to get the flow at 13 psi first. I do this by putting in numbers until things line up.

Enter 14.5 psi in the fuel pressure box. Then enter different flow ratings until in the right hand box (Misc Data) it shows that the injector is flowing the 65 #/hr.

And 61.5 #/hr does the trick. So the injectors flow 61.5#/hr at 13 psi. Which is real close to the 61 #/hr 350 injectors that came stock on most 5.7L engines.

Then use the 61.5 #/hr and the fuel pressure that you are using.

Note, be careful if using a VRFPR and TP V5. Mark reversed the order of the tables going from V4 to V5, so can't copy & paste into V5.

RBob.

 

Ok. I will see what it comes up and go from there

thanks.

 

Ok so I identified my injector. I was incorrect. holley states it flows 60 PPH @ 12 PSI, and 85 PPH @ 21 PSI.

I am having trouble with the first portion. Getting the utility to flow the 13 PSI first. I really dont understand what that means. I hate being a pain. I almost need screen shots to help guide me along.

 

Picture attached. I put 12 psi in for the current fuel pressure. Then changed the Injector Flow Rate value until the injector showed an actual flow of 60 #/hr.

You can see that in the box to the right, Misc Data.

And the flow rate at 13 psi ends up as 62.4 #/hr.

RBob.

 

Ok and so from there I do not touch the 62.4 again, but then change the PSI to what I am running and I should be good?

I got that same # but it did not seem right to me. But if it is. Then all fine by me. Thanks Bob.

 

Yes, just change the fuel pressure to what you are running. The injector flow rate is 62.4 #/hr at 13 psi.

RBob.