How bout full throttle?

 

haven't got that far yet

 

So, it looks like it is not disputed that the 2004 does not gain fuel pressure at higher rpm.

What about the 2003 and earlier? Anyone?

 

I have an '03 and I just hooked up my fuel pressure gauge tonight.

Seems that I get 53 at idle and 50 with a dip to 49 maybe when I back out of the throttle when I am just cruising along. I saw a brief 67 at WOT just before the 2/3 shift at 5700 rpm with a pretty consistant 63-64 at WOT. The fuel pressure on the '03 sure seems to move around a lot.

 

64 psi initial charge, 63psi idle, 63 psi most conditions, 61psi WOT at the top of second gear and on a WOT 2-1 downshift, 66psi on deceleration of a WOT run, this is at 7psi of boost

 

Good info. Keep in mind that the 7 psi of boost (intake pressure) won't be seen at the fuel rail. Meaning that you'll only see the 61 psi at fuel throttle. The injector will see a differential that will not show up on a gauge. The injector has to overcome the 7psi of boost in the intake to spray the fuel. So you would have an effective fuel pressure of 53-54 psi.

If we had the 03 and earlier type system and were able to achieve 61 psi + have the boost referenced increase in fuel rate (in your case 7psi) we would see fuel pressure jump to 68 psi. Then when the pressure differential was considered... 68psi fuel rail pressure - 7 psi intake pressure (resisting flow) = 61 psi effective fuel pressure. If we truly had that 61 psi of effective pressure the 42 lb injectors probably would be big enough for the 04 and 05's to fuel 550hp.

 

On my 2000 I see 50-51 at idle, 58-60 WOT and anywhere inbetween on part throttle conditions. I will see less than 50 on decel.