hodge Posted January 3, 2011 Share Posted January 3, 2011 Should my static fuel pressure be set higher than normal 38 psi. What pressure are you guys running. My setup is as follows Bosch 044 pump -8AN PTFE fuel line 2 x -6AN PTFE fuel lines to rail Veilside fuel rail 1600cc RC injectors (lo-imp) Aeromotive FPR -6AN Line from rail to FPR. Thanks John Quote Link to comment Share on other sites More sharing options...
johnny g Posted January 3, 2011 Share Posted January 3, 2011 Well, your 1600cc injectors will be measured at 43.5psi (or 3bar), probably. So your injectors at that pressure are around 1390cc/min. The Bosch does like higher pressures, so maybe 4bar? What are your injectors safe too? Quote Link to comment Share on other sites More sharing options...
hodge Posted January 3, 2011 Author Share Posted January 3, 2011 You've lost me there Johnny. The current static pressure acconding to the FPR gauge is 50 psi. Wasn't sure if it was a little high. Quote Link to comment Share on other sites More sharing options...
johnny g Posted January 3, 2011 Share Posted January 3, 2011 You've lost me there Johnny. The current static pressure acconding to the FPR gauge is 50 psi. Wasn't sure if it was a little high. Don't think there's anything wrong with that mate. 50psi is about 3.4bar. It'll only matter as much once the car is mapped, it's based relative from that IIRC. Quote Link to comment Share on other sites More sharing options...
SupraHuman Posted January 3, 2011 Share Posted January 3, 2011 IIRC stock fuel pressure is around the 45psi mark, so 50 can't hurt. Quote Link to comment Share on other sites More sharing options...
Steve Posted January 3, 2011 Share Posted January 3, 2011 Stock fuel pressure is around 36-38 psi static. Quote Link to comment Share on other sites More sharing options...
johnny g Posted January 3, 2011 Share Posted January 3, 2011 Higher fuel pressure will give better atomisation Quote Link to comment Share on other sites More sharing options...
hodge Posted January 3, 2011 Author Share Posted January 3, 2011 What do you mean by atomisation Johnny Quote Link to comment Share on other sites More sharing options...
johnny g Posted January 3, 2011 Share Posted January 3, 2011 The spray, the mist will be finer, smaller atoms and will burn better. Quote Link to comment Share on other sites More sharing options...
Jurgen-Jm-Imports Posted January 3, 2011 Share Posted January 3, 2011 3 bar to 3.5 mate is were you want for now then ryan will adjust it. (once he has it mapped) Quote Link to comment Share on other sites More sharing options...
Rob_Mitchell Posted January 3, 2011 Share Posted January 3, 2011 i have heard 3 bar from elsewhere but im lost with s**T like this it goes way over my head. Quote Link to comment Share on other sites More sharing options...
hodge Posted January 3, 2011 Author Share Posted January 3, 2011 I'll leave it alone then until it's mapped. Quote Link to comment Share on other sites More sharing options...
J_Supra_07 Posted January 3, 2011 Share Posted January 3, 2011 Your presure will be fine. Ryan will take it up or down when he maps it. Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 6, 2011 Share Posted January 6, 2011 The spray, the mist will be finer, smaller atoms and will burn better. Mmm I must comment If you run too high a pressure then you risk disrupting the spray pattern, otherwise I've not heard of a change in spray pattern according to pressure. If it was that sensitive to changes in PSI then we'd all be in trouble, as the FPR increases pressure as boost builds. 1.4bar means a change of over 20psi in fuel pressure from static. Also it doesn't make the atoms smaller, otherwise you'd get some serious detonation I'm sure you meant "atomisation" Quote Link to comment Share on other sites More sharing options...
dandan Posted January 6, 2011 Share Posted January 6, 2011 If it was that sensitive to changes in PSI then we'd all be in trouble, as the FPR increases pressure as boost builds. That's a little misleading there though Ian. The pressure drop across the injector stays the same because the outlet is atmanifold boost pressure and the inlet is always at the rail's "static + boost referenced" pressure so irrespective of what boost you see, the pressure drop across the injector is the same. Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 6, 2011 Share Posted January 6, 2011 That's a little misleading there though Ian. The pressure drop across the injector stays the same because the outlet is atmanifold boost pressure and the inlet is always at the rail's "static + boost referenced" pressure so irrespective of what boost you see, the pressure drop across the injector is the same. Yep, but the fuel spray pattern is still being pushed harder into higher resistance air. The pressure drop stays the same but the forces acting upon both sides increase. If you pushed 1psi one side of a sandwich and 1psi the other, you'd get a differently shaped sandwich than if you then did 50psi one side and 50psi the other, even though the pressure differential stays the same So my strained analogy shows that the spray pattern could be affected by rising fuel pressure as boost comes on, if it were indeed affected by increased static pressure as well. But none of it seems to bother atomisation or spray pattern or whatever anyway. I'm fairly sure that if injector spray patterns varied significantly depending on static pressure you'd see it in the advertising blurb and technical data, and companies would be espousing their market-leading pattern consistencies over class-leading pressure ranges etc.. Quote Link to comment Share on other sites More sharing options...
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