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aftermarket fuel system 74 rx4

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Old 07-14-12, 12:38 PM
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Shredding Tires

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ON aftermarket fuel system 74 rx4

so heres a bit of backround.

got this beauty supercharged rx4 not to long ago. stock fuel pump crapped out on me so i decided it was time for an upgrade. i was told holley blue was the way to go, a 14 psi external fuel pump, with a 4.5- 9 psi holley return style regulator. i was hoping to be able to dial the 14 psi pump down to 4.5 with the regulator, but clearly i can not. i did however wire in a stock FC3S fuel pump resistor pack and got it down to roughly 8-9 psi.

so i know i need a lower output fuel pump. im thinking the holley red will do me well as its output psi is only 7 psi.

what do you guys think? should i even get a lower rated pump?? I need to be able to get some 6an fittings or npt adapters on them so the inlet and outlet should be threaded.

thanks everyone. hopefully ill have my fuel system all figured out by the end of this weekend.
Old 07-14-12, 04:24 PM
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RX for fun

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I never had any luck getting fuel pressure down to below 5psi using holley blue with holley or mallory low psi regulator tho specifically told rep at summitracing my goal.
So i ended up running 2 regulators in series but got tired of looking at it so i swtched back to carter 7psi.

I always run an independent wire with 40amp relay to fuel pump to ensure it gets the proper voltage/amps.

The stock line is only 5/16 or -6 but it wont hurt to run -8. Holley red and carter will do fine.
Old 07-14-12, 07:36 PM
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Shredding Tires

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Perfect, this is what I began to assume after having these troubles.

I'm not used to the old school carbs with lower psi requirements. I'm just getting into the old school. I currently have a second gen with big single and standalone and whatnot, so needless to say a supercharged carb is the polar opposite.

Anyone wanna buy a brand new holley blue pump??? Haha used for about 5 minutes :p

Originally Posted by Siraniko
I never had any luck getting fuel pressure down to below 5psi using holley blue with holley or mallory low psi regulator tho specifically told rep at summitracing my goal.
So i ended up running 2 regulators in series but got tired of looking at it so i swtched back to carter 7psi.

I always run an independent wire with 40amp relay to fuel pump to ensure it gets the proper voltage/amps.

The stock line is only 5/16 or -6 but it wont hurt to run -8. Holley red and carter will do fine.




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