Yeah, I missed the second post on this thread... https://www.nopistons.com/forums/pub...1047683664.gif ...



DuMaurier7, something's sounds wrong with your pump/pump wiring. I'm using 2 FD pumps at 45 psi static fuel pressure and it hold thru 9000 rpms/15 psi boost. What gauge wire are you using for your pumps? Are you sure your getting the right voltage to them?

I am using 8 gauge amp. wire from the battery streight to the pump , my battery is at the back so the distance is short , the ground wire is also connected at the batterys grounding point in the hatch and is switched via the HALTECHS pump control system which I wired to switch an additional relay. I found that the supply voltage from the HALTECHS's system (the orange coloured wires) wasnt capable of supplying enough power when the battery is placed at the back , although I used 0 gauge oxygen free audio wire (expensive stuff) to connect the battery to the +ve connection point up front , before switching around the voltage supply , the fuel pressure would keep falling off at as little as 10 psi boost.

A bit more info , at WOT in third gear my max . exhaust temp. was about 1440 deg . F (782.2 C ) , max intake temp without W.I active was 95deg F ( GOOD ol' large NPR) and coolant temps was at 180 F max.

Good numbers!

Yeah you should be seeing around 40psi fuel pressure at idle, and add 1psi per pound of boost. Nothing wrong with 88% duty cycle, just keep it out of the 90's.

You shouldn't be having any pressure problems with that pump, yet. You might want to check the fuel filter. Even if you were very careful assembling your fuel system, sometimes there is still a little bit of crap that gets in the system, and takes a little while to catch in the filter. I would try pulling the filter out of the system and backflushing the filter to see if there is anything in it. What size line are you using out of the pump to the rail?

i am using -8AN all the way up to the engine then it splits int two -6AH hoses to feed the rails.

Where do you have the pump mounted? Is it lower than the gas tank?

Not it isn't lower , but it is in line with the suction point which is at the rear of a sump that I had attached to the underside of the tank. I have the pump mounted on to the black, metal piece of sub-frame that goes between th tank and the Diff , I bolted the pump on to a flat rectangular piece of aluminum , then mounted that on to the sub-frame.

I am running 50 PSI base with this pump and My pressure holds all the way to redline, but at 24 PSI I checked the peak injector duty and it was about 98%. The 24 was insane compared to the 18 PSI I normally ran. I wanted to try 25 but wont even think of it untill I get some room on the injector duty.



I am using 10 AN to the pump and 8 AN feeds to each rail. My pump is lower then the sump. I wonder if some crud did not get cought in the filters? What filters are You using (micron size)? I used teflon steel braided lines and the fittings are a bit restrictive so I am changing to rubber stainless lines and Earls fittings as the bends flow better. I am not sure if it will help but I am going to change them out.