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fuel pressure ?'s

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Old 08-23-2008, 07:51 AM
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Default fuel pressure ?'s

My last trip to the dyno i ran out of fuel a 5,200 RPM, (20psi) with #60 injectors and a single 255 in tank, stock fuel rails. I'm seeing #10 of boost after 5,000rpm.
I installed a kenne bell boost a pump last week. I have a fuel gauge that i plumed from the fuel rail to the back of the hood so I can see it while driving,this is not a electric gauge. When going WOT the fuel pressure holds at 55 to 60 psi untill I cross the 5,500rpm range then it drops to 40/45 psi and holds to 6,700rpm. So my ? is do i need to maintain 60 psi of fuel pressure at all times? Do i need two pumps? I'm hoping to get back to the dyno in the next month to finaly have it tuned again and I dont want to spend $500 to find out I need more fuel again. Any sudgestions would be great.

Last edited by conan; 08-23-2008 at 08:12 AM.
Old 08-23-2008, 08:51 AM
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I would put another pump in. If pressure is dropping like that then your streachin that pump. There is a sticky in the fuel or here on how to diy twin pumps way less than a sponser one and its used on a 800 hp car.
Old 08-24-2008, 09:52 AM
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Originally Posted by OUTLAWZ RACING
I would put another pump in. If pressure is dropping like that then your streachin that pump. There is a sticky in the fuel or here on how to diy twin pumps way less than a sponser one and its used on a 800 hp car.
Thanks for the info. I found the sticky in the fuel section on the dual pumps.
Old 08-24-2008, 10:00 AM
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I just wish I found it befor I sepnt 2k on a fuel setup but im happy with it.
Old 08-24-2008, 10:08 AM
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Originally Posted by OUTLAWZ RACING
I just wish I found it befor I sepnt 2k on a fuel setup but im happy with it.
I hear you... if i new a year ago what i know now i wouldn't be pulling the fuel tank for the 4th time I guess you live and learn. Thanks for the help.
Old 08-25-2008, 09:33 AM
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how much power were you making at that rpm...
Old 08-25-2008, 10:34 AM
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Originally Posted by sevanseriesta
how much power were you making at that rpm...
We stoped tuning @ 5,100 rpm and it made 543rwhp 502wrtq. Fuel pressure went to 20psi around that rpm. Now with the kenne bell boost a pump turned up all the way fuel pressure holds 55 psi untill 5,500 rpm then drops to 45 psi and holds there all the way to 6,800 rpm's.
Old 08-25-2008, 11:09 AM
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I would save yourself the problems later and just do the dual pumps now. What you have now is like a bandaid. It could be tuned around being that it doesn't drop below 45 they could tune around the problem but you are better off doing it right the first time. Your set up is similar to mine. forged 347, ported stock heads, 224/232 .581/.595 114lsa, 1 7/8 kooks, mufflex, 60# injectors and I have dual intanks. Seeing 12psi I made 605rwhp, 522rwtq
Old 08-25-2008, 11:20 AM
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Thanks for the info. I want to have everything right this trip to the dyno. I have to go from park city UT to las vegas to have it tuned this time and its about a 6 hour drive not to mention $4.40/gal for diesel to tow it down there. Any imput on keeping the kenne bell boost a pump in with the 2 fuel pumps or just the pumps.
Old 08-25-2008, 12:02 PM
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I would run just the 2 pumps. Also do you have a adjustable FPR I have a boost referenced one and I am running around 60psi @idle and damn near 70psi @6800rpm. I also did 8AN feed lines and used my stock feed line as a return line.
Old 08-25-2008, 12:12 PM
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I dont have a adjustable FPR just the stocker.



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