Mechanical pump, or existing in-tank pump?

shnipplelicken · July 8th, 2007, 11:37 PM

ok, so heres whats up. I just did my first engine swap on my '90 stang. The V8 is from a '79 stang. My problem, or at least one of my problems, is that my car used to be EFI and the engine is carburated. My question is: can the mechanical pump still suck gas through the pump in the tank, even if the in-tank pump is disabled? Can I just use the in-tank pump to send fuel to the carb and just remove or bypass the mechanical pump? How should I go about doing this?

neverfastenough1 · July 9th, 2007, 05:55 AM

Definitely go with electric if possible. Reason being, mechanical pumps use hp to pump. You can use the in tank pump you have with a pressure regulator.

JBIGBOOTSY · July 9th, 2007, 08:28 AM

mallory makes a specific fuel pressure reg. for using the in-tank pump with a carb. You will not be able to pull fuel through the intank pump if you use the mech. pump.

neverfastenough1 · July 9th, 2007, 08:59 AM

Originally Posted by JBIGBOOTSY

mallory makes a specific fuel pressure reg. for using the in-tank pump with a carb. You will not be able to pull fuel through the intank pump if you use the mech. pump.

Yeah, you would have to pull the pump off and run a line from the pickup tube to the bottom of the tank. With a screen.

shnipplelicken · July 11th, 2007, 08:04 PM

ok, I guess its the electric pump FTW, but whats the exact regulator that I should use? Everything I've seen is between 30 and 60 psi. I was told that I should regulate the flow to about 6 or 7 psi to the carb. True?

JBIGBOOTSY · July 11th, 2007, 08:34 PM

mallory fuel pressure reg. part #4309

C MY 4D · July 11th, 2007, 09:21 PM

Yes electric pump FTW...... you need a 0-15psi regulator with a return bypass. I just got done converting my car over to carb and am still using my EFI BG Mighty Sumo pump. As long as the return line is large enough it will work great.

ryans88gt · July 11th, 2007, 11:47 PM

Yeah +1 on the return line.
I have a 140 gph out of tank electric pump designed for carbs with a 3/8" feed line. Originally I tried using the stock return line and the lowest I could get the fuel pressure down to was like 12 PSI. So I switched the routing around so that the factory feed line is my return line and this brought the pressure down to about 7-8 PSI. However, even with the 5/16" feed line as my return I can't turn the pressure down past 7-8 PSI...

With the factory EFI pump I could regulate between 3 PSI and 30 PSI using the factory feed and return line.

July 8th, 2007, 11:37 PM	#1
shnipplelicken Newbie Join Date: Jul 2007 Location: Hollywood, MD Posts: 4	Mechanical pump, or existing in-tank pump? ok, so heres whats up. I just did my first engine swap on my '90 stang. The V8 is from a '79 stang. My problem, or at least one of my problems, is that my car used to be EFI and the engine is carburated. My question is: can the mechanical pump still suck gas through the pump in the tank, even if the in-tank pump is disabled? Can I just use the in-tank pump to send fuel to the carb and just remove or bypass the mechanical pump? How should I go about doing this?

July 9th, 2007, 05:55 AM	#2
neverfastenough1 Hardcore Enthusiast 2002 Mustang GT Join Date: May 2007 Location: Savannah, Ga Posts: 1,340	Definitely go with electric if possible. Reason being, mechanical pumps use hp to pump. You can use the in tank pump you have with a pressure regulator. __________________ 2007 Explorer Sport Trac, 292 HP, Stock 2002 Mustang GT

July 9th, 2007, 08:28 AM	#3
JBIGBOOTSY Hardcore Enthusiast 1990 LX hatch Join Date: Aug 2006 Location: Hobart Indiana Posts: 1,922	mallory makes a specific fuel pressure reg. for using the in-tank pump with a carb. You will not be able to pull fuel through the intank pump if you use the mech. pump. __________________ Originally Posted by HELLRAZR94 what up pussy lets stop talking shit i would love for your pussy ass to come to cali so that i can show you what im about, when you get here let me know and i will come to you fag

July 11th, 2007, 08:34 PM	#6
JBIGBOOTSY Hardcore Enthusiast 1990 LX hatch Join Date: Aug 2006 Location: Hobart Indiana Posts: 1,922	mallory fuel pressure reg. part #4309 __________________ Originally Posted by HELLRAZR94 what up pussy lets stop talking shit i would love for your pussy ass to come to cali so that i can show you what im about, when you get here let me know and i will come to you fag

July 11th, 2007, 11:47 PM	#8
ryans88gt MM Fanatic Join Date: May 2007 Location: Bloomington, IL Posts: 3,553	Yeah +1 on the return line. I have a 140 gph out of tank electric pump designed for carbs with a 3/8" feed line. Originally I tried using the stock return line and the lowest I could get the fuel pressure down to was like 12 PSI. So I switched the routing around so that the factory feed line is my return line and this brought the pressure down to about 7-8 PSI. However, even with the 5/16" feed line as my return I can't turn the pressure down past 7-8 PSI... With the factory EFI pump I could regulate between 3 PSI and 30 PSI using the factory feed and return line. __________________ 89 LX 515 hp 497 ftlbs 11.3 @ 125 mph 88 GT 11.4 @ 118

July 11th, 2007, 08:04 PM	#5
shnipplelicken Newbie Join Date: Jul 2007 Location: Hollywood, MD Posts: 4	ok, I guess its the electric pump FTW, but whats the exact regulator that I should use? Everything I've seen is between 30 and 60 psi. I was told that I should regulate the flow to about 6 or 7 psi to the carb. True?

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