How much fuel pressure is recommended at idle? What is maximum pressure, before it starts to push past needle and seat? Holley 850 DP and Holley blue electric pump. Thanks!
The standard Holley needle and seat will hold back 8-9 lbs. of pressure. They do have a high pressure version that is good to 11 psi.
I try not to run more than 6 1/2 -7 psi even though I do use the high pressure needle ans seat. I use the new titanium model.
This feeds 2 Dominators and just under 1000 HP just fine.
[This message has been edited by Racing Ray (edited April 04, 2002).]
Thank You Racing Ray!
Racing Ray, a few more questions, if I may. If I set idle fuel press at, say, 8lbs, will it drop at WOT. Should it? What should be minimum press at WOT? I have heard 5-6lbs. Also, I believe you recommended a NGK plug a while back. I have to stick with my 330hp 454 for a little while longer. Could you recommend a decent plug, por favor? Thanks again!
Fuel press. should be the same at WOT as it is at idle. ANY drop at all indicates the engine is running out of fuel and the pump and/or the lines are not big enough to handle the demand of the engine.
The recommended plug for Mercrusier's 330 engine is NGK BR6FS. 5-6 psi at WOT is ok to feed 330 HP.
058 is correct in saying you should strive to design your fuel system to maintain full pressure throughout the RPM band.
There is a reason you are getting this pressure drop. If you describe your system maybe I can explain why.
Thanks again Ray! Hey, even a litlle help from a Ford guy http://free.***boat.net/ubb/biggrin.gif j/k. Thanks 058!
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