Fuel Pump Question
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
You could. But you should do some research.....most in the tank pumps (85 and newer) are made to feed the fuel injectors and are pushing 40-60 PSI from the pump to the FPR. Most external pumps are designed to feed carburetors that usually require only 8-12 PSI.
For FI cars, you have a return fuel line going from the FPR to bleed off the excess fuel supplied by the pump back to the tank. The carburetor feed engines usually have a float valve that shuts off the fuel supply to the bowl and no return line.
For FI cars, you have a return fuel line going from the FPR to bleed off the excess fuel supplied by the pump back to the tank. The carburetor feed engines usually have a float valve that shuts off the fuel supply to the bowl and no return line.
Thread Starter
Le Mans Master
Joined: Feb 2005
Posts: 6,475
Likes: 565
From: Clearwater Florida
You could. But you should do some research.....most in the tank pumps (85 and newer) are made to feed the fuel injectors and are pushing 40-60 PSI from the pump to the FPR. Most external pumps are designed to feed carburetors that usually require only 8-12 PSI.
For FI cars, you have a return fuel line going from the FPR to bleed off the excess fuel supplied by the pump back to the tank. The carburetor feed engines usually have a float valve that shuts off the fuel supply to the bowl and no return line.
For FI cars, you have a return fuel line going from the FPR to bleed off the excess fuel supplied by the pump back to the tank. The carburetor feed engines usually have a float valve that shuts off the fuel supply to the bowl and no return line.
Thread Starter
Le Mans Master
Joined: Feb 2005
Posts: 6,475
Likes: 565
From: Clearwater Florida
..... Perhaps ... I'm no expert either , but , I have a high flow pump in the tank now and I also have a high flow external that's currently lounging around on the shelf ... I want to put the slacker to work even if its redundant ... the reason I'm asking is that I didn't want to defeat the purpose for some un-thought of reason ....... I am hoping someone else may have done this and would share their experience ........ being a long holiday weekend this is the only place I felt I could expect some expert advice ..................
Racer
Joined: Oct 2006
Posts: 438
Likes: 14
From: Tucson/Santa Paula AZ/CA
2017 C4 of Year Finalist
........... This would be used to push fuel to an EFI external pump ... just looking to over-feed the rails ... depending on mounting location , which is somewhat limited on the Corvette , a lift pump is almost a necessity to feed an external pump ... its my understanding that EFI pumps are not as efficient pulling fuel as they are pushing it ...... carbs are for classic cars anyway ... not for C4s ........
http://www.fuelinjectorconnection.co...widercalc.html
Mick
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Thread Starter
Le Mans Master
Joined: Feb 2005
Posts: 6,475
Likes: 565
From: Clearwater Florida
............ You also have a bottom sump in your fuel tank ... I'm running the factory fuel tank and an external pump would need to draw fuel up and out of the stock fuel lines ... I do believe there's a pretty good reason the mfr's all want to put EFI fuel pumps IN the tank ... what I am interested in doing is providing an overkill fuel supply to my engine with parts already owned ...... Is there some reason why my intention wouldn't work ? ... I really wasn't looking for alternatives ... just enlightenment ..........
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
This would be used to push fuel to an EFI external pump ... a lift pump is almost a necessity to feed an external pump ...
the reason I'm asking is that I didn't want to defeat the purpose for some un-thought of reason .....
I really wasn't looking for alternatives ... just enlightenment ....
the reason I'm asking is that I didn't want to defeat the purpose for some un-thought of reason .....
I really wasn't looking for alternatives ... just enlightenment ....
or in tank pump is trying to pressurize ext pump ( a restriction ) pumps require fuel flow for cooling
I suspect the only way to make it work properly would be to have the in tank pump feeding a surge tank ( like the ricers !) with a return to the tank
so it operates completely independent of the ext pump and the tank then supplies the prime for ext pump.
Last edited by vetteoz; Jun 2, 2012 at 03:55 AM.
Race Director
Joined: Apr 2003
Posts: 17,698
Likes: 1,667
From: moraga ca
............ You also have a bottom sump in your fuel tank ... I'm running the factory fuel tank and an external pump would need to draw fuel up and out of the stock fuel lines ... I do believe there's a pretty good reason the mfr's all want to put EFI fuel pumps IN the tank ... what I am interested in doing is providing an overkill fuel supply to my engine with parts already owned ...... Is there some reason why my intention wouldn't work ? ... I really wasn't looking for alternatives ... just enlightenment ..........
Last edited by 383vett; Jun 2, 2012 at 03:21 PM.
Thread Starter
Le Mans Master
Joined: Feb 2005
Posts: 6,475
Likes: 565
From: Clearwater Florida
I was running this same setup when I had the stock tank in the car. The fuel pump intake was hooked up to the stock fuel line coming out of the tank. Within the tank, I replaced the stock pump with a length of braided fuel line with a sock on the end. This pump was able to pull fuel out the top of the tank and into the motor with no problems. Remember, if the pump is mounted below the tank, the fuel will essentially sipon out of the tank without needing to be sucked out.
Race Director
Joined: Apr 2003
Posts: 17,698
Likes: 1,667
From: moraga ca