So you may gain a more consistant spray pattern if FP drop is minimized (with propper injector), pump life extended...what other perceived benefit?

 

I don't know much about the spray pattern, if you can maintain a 3 bar differential between fuel rail pressure and manifold pressure that will at least make tuning easier (If the pressure drops you will have to compensate in the tune). If I am trying to maintain a 4 bar differential my fuel pressure is going to be close to 75psi, I would imagine the fuel pump wouldn't last as long that way. The main reason I would want to do this is so I can get by without using a huge, expensive aftermarket inline that may not be as reliable.

 

Logical. Do it and report!

 

Hmmm....maybe I should turn my pressure down some. I have plenty of injector. Interesting.

 

On a side note, if a FPR is "going bad" and my running fuel pressure is 50psi versus the spec of 55psi minimum what will be the side effects....a lean code possibly? or some powere loss and no code? I'm not trying to jack the thread but I was under the impression that the injectors need to see a steady 55psi+ while running.

 

Yes, because your IFR is tuned that way. The PCM doesn't know how much fuel or at what pressure it's being injected, it has to be set in the program so if your pressure is dropping and the settings are the same then you are supplying less fuel to your injectors than required.

 

I see. thanks alot trever.

 

You're on the right track. There was some recent discussion on this topic that might be helpful: https://www.performancetrucks.net/fo...d.php?t=427224

 

That thread is a great read. I think I'm going to go ahead and drop my pressure to 3 bar.

 

Dropped the fuel pressure to somewhere around 43-44 psi. The pitch of the pump increased quite a bit. My 96# injectors were rated 96 lb/hr at 3 bar, so I had them in the tune as about 110 lb/hr to match the 4 bar fuel pressure. I just turned the pressure down, changed the IFR table back to 96 lb/hr, and everything worked fine without having to tweak any of the airflow tables at all. Very simple At 5600 RPM and 10psi I'm still only seeing 51% IDC max, lol.