Electric fuel pump Q - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Longhorn Man · 09-01-2004, 10:59 PM

I know with a carb you want to keep the fuel under 7 PSI....but is 2 1/2 to 4 PSI a bit low for a stock engine over 400 cubes? (No GPM rateing)

fast71 · 09-01-2004, 11:08 PM

Andy thats alittle low . needs to be around 5 or 6.

Longhorn Man · 09-02-2004, 07:50 PM

That's what I was thinking...thanks.

Tx Firefighter · 09-02-2004, 07:59 PM

The 2 1/2 to 4 makes me happy. Every spec I've ever remember reading said under 5 psi max. Edelbrock/ Carter carbs are picky abut too high pressure anyway.

Longhorn Man · 09-02-2004, 08:07 PM

Hmmm....I would like to buy this pump..it is dirt cheap, readily avalible, and supposed to be quiet too.

Anyone wanna break the tie?

I'm not gonna be racing, but I'll be honest, I kinda dog my vehicles a little bit. This is for the 425 Cad motor, and right now it has a quadra jet, but will probably end up with a 750 edelbrock on top.

cableguy0 · 09-02-2004, 11:24 PM

andy generally lower pressure means lower volume as well as far as being able to flow enough to keep up with that big block. i would stick with a mechanical pump then upgrade with a good electric later on. that is if the mechanical isnt up to the task which it should be

Alexis · 09-03-2004, 02:03 AM

I've been told to stay under 7 by all means. i got a summit pump with a regulator. Haven't hook it up yet still got more things to do on the list. Good luck and what is up with the longhorn?

Longhorn Man · 09-03-2004, 02:38 AM

I was going to stay with the mechanical pump...honestly, I hate electric ones. However, the Caddy fuel pumps all have a port for a fuel return line, and my truck does not have this. I did the 'bolt in the return line' trick, but the pump started leaking. I grabbed another pump. and the exact same thing happened. I'm asuming this is becouse of the blocked off return line.

I was thinking about the flow rate, and true, it does generally go down with pressure...and this pump seems pretty low. (I was going to run it on a relay so it would be up near 4 psi all the time)

I guess I'll look for another well priced easily found unit.

Russell · 09-03-2004, 09:34 AM

I picked up a 200 PSI @ 43 GPM for about 130 bucks US + shipping. The guy who sells them says he has been using one on his TPI V8 S-10 for a couple years now with no problem. Says they are real noisy though

stllookn · 09-03-2004, 02:23 PM

Andy, Try plumbing the return line back into the inlet of the pump between the tank and the inlet filter. As long as you don't have an inlet check valve in the system between the tank and where you plumb it in...it should work fine.

09-01-2004, 10:59 PM	#1
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Electric fuel pump Q I know with a carb you want to keep the fuel under 7 PSI....but is 2 1/2 to 4 PSI a bit low for a stock engine over 400 cubes? (No GPM rateing)

09-01-2004, 11:08 PM	#2
fast71 Drive it like U stole it Join Date: Mar 2000 Location: tunnel hill ,GA /Chatt,TN Posts: 956	Andy thats alittle low . needs to be around 5 or 6. __________________ 71 custom 10 swb 72 nova ss 72 nova custom 87 s10 96 burb 94 camry 53 5 window 3100

09-02-2004, 07:59 PM	#4
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	The 2 1/2 to 4 makes me happy. Every spec I've ever remember reading said under 5 psi max. Edelbrock/ Carter carbs are picky abut too high pressure anyway. __________________ I'm on the Instagram- @Gearhead_Kevin

09-02-2004, 11:24 PM	#6
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	andy generally lower pressure means lower volume as well as far as being able to flow enough to keep up with that big block. i would stick with a mechanical pump then upgrade with a good electric later on. that is if the mechanical isnt up to the task which it should be __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

09-03-2004, 09:34 AM	#9
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	I picked up a 200 PSI @ 43 GPM for about 130 bucks US + shipping. The guy who sells them says he has been using one on his TPI V8 S-10 for a couple years now with no problem. Says they are real noisy though __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

09-02-2004, 07:50 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	That's what I was thinking...thanks.

09-02-2004, 08:07 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Hmmm....I would like to buy this pump..it is dirt cheap, readily avalible, and supposed to be quiet too. Anyone wanna break the tie? I'm not gonna be racing, but I'll be honest, I kinda dog my vehicles a little bit. This is for the 425 Cad motor, and right now it has a quadra jet, but will probably end up with a 750 edelbrock on top.

09-03-2004, 02:03 AM	#7
Alexis Member since 2000 Join Date: Dec 2000 Location: Mountain View Ca / Mexico Posts: 7,874	I've been told to stay under 7 by all means. i got a summit pump with a regulator. Haven't hook it up yet still got more things to do on the list. Good luck and what is up with the longhorn?

09-03-2004, 02:38 AM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	I was going to stay with the mechanical pump...honestly, I hate electric ones. However, the Caddy fuel pumps all have a port for a fuel return line, and my truck does not have this. I did the 'bolt in the return line' trick, but the pump started leaking. I grabbed another pump. and the exact same thing happened. I'm asuming this is becouse of the blocked off return line. I was thinking about the flow rate, and true, it does generally go down with pressure...and this pump seems pretty low. (I was going to run it on a relay so it would be up near 4 psi all the time) I guess I'll look for another well priced easily found unit.

09-03-2004, 02:23 PM	#10
stllookn Saving 1 truck at a time! Join Date: Aug 2001 Location: Kent, WA Posts: 6,465	Andy, Try plumbing the return line back into the inlet of the pump between the tank and the inlet filter. As long as you don't have an inlet check valve in the system between the tank and where you plumb it in...it should work fine. __________________ '68 C20 Longhorn 50th Anniversary 400/TH400 '68 C20 Longhorn 50th Anniversary 468/TH400w/buckets '72 C20 Halfhorn (Longhorn w/o cab and front clip) '69 Flxible Cruiser (look up ugly in the dictionary)

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