I know on my old tbi I just changed the spring in the fuel pressure regulator to get more fuel.

But on m 5.3 it looks confusing. Is the regulator vaccum referenced on the return fuel system?

In EFI live the injectors flow all the same no matter what manifold vaccum in my tune?

So is there anyway to get more fuel pressure for more flow im running e85 with a 1.16-1.20EQ PE and getting a 94-96%duty cycle at WOT?

My truck is a 2000 but I looked on a 2002 and the flow rates are all the same too. I looked on a 2006 but that has a diffrent flow rate?

 

Thats the difference with Return and Returnless fuel systems..
WHy would you want to raise your FP?
Just get some larger Injectors and be done with it..

 

Right now im at a max of 96% DC. But my grams per cylinder is low right now at about .65max sometimes its at a max of .71 so im thinking im going to go static. It dosent seem like my truck not being flex fuel should be able to support pure e85 on the stock injectors.


But instead of having to change injectors there is not a way to easy make the regulator give more pressure?

Why does my fuel pressure regulator have a vaccum line on it if it dosent regulate fuel pressure as vaccum changes?

 

when you go wide open throttle the vacuum goes to zero at that causes the fuel pressure to go up, I thihnk it is like a switch it is either at one pressure or the other.

 

Yeah but in my tune on efi live it says the injectors flow the same at ever MAP pressure?

 

I dont know anything about tuning but I do know my fuel pressure goes up at the decrease in vacuum.
Tuning is something I have not looked at any...
Dave

 

I think the regulator mechanically compensates for the change in manifold pressure and thats how it keeps a constant grams per cyl. The tune uses the MAP to determine engine needs.

I think there are adjustable regulators that still move with vac. Hopefully someone will chime in that has done this. I am curious too.

 

Yeah this is confusing do you mean that since their is vaccum in the manifold more fuel will actually come out of the injectors becuase their is negative pressure in the port at part throttle?

So is their any tricks I can do to get a little more pressure out of it so my duty cycle wont be 100+ with e85?

 

Yeah this is confusing do you mean that since their is vaccum in the manifold more fuel will actually come out of the injectors becuase their is negative pressure in the port at part throttle?

So is their any tricks I can do to get a little more pressure out of it so my duty cycle wont be 100+ with e85?

 

here's what I'm thinking

http://www.hksusa.com/products/?id=630

If you try one, post-up, eh?