Gas Tank intake theory help
Thread Starter
Staging Lane
Joined: Feb 2006
Posts: 96
Likes: 0
From: Denver, CO
Gas Tank intake theory help I'm putting together my gas tank intake, and I have a question on theory.
I got everything put together mostly with my stock intake system with also using my aftermarket pump. It has a fuel return "cup" that I was able to mount my pump in. It has a one way valve in the bottom so the fuel level in the cup is always at least what the level of the tank is.
I was expecting that the pump intake being near that valve would pull fuel in to fill the "cup" up when the tank is 1/2 empty so my reserve cup would always be full. It doesn't seem to work that way though. The cup is never higher than the level of the rest of the tank. Doesn't that mean that when I'm lower on gas that if I hit a hill then I won't have much reserve to get off that hill? Is it supposed to fill up the "cup" or only the level of the rest of the tank?
I got everything put together mostly with my stock intake system with also using my aftermarket pump. It has a fuel return "cup" that I was able to mount my pump in. It has a one way valve in the bottom so the fuel level in the cup is always at least what the level of the tank is.
I was expecting that the pump intake being near that valve would pull fuel in to fill the "cup" up when the tank is 1/2 empty so my reserve cup would always be full. It doesn't seem to work that way though. The cup is never higher than the level of the rest of the tank. Doesn't that mean that when I'm lower on gas that if I hit a hill then I won't have much reserve to get off that hill? Is it supposed to fill up the "cup" or only the level of the rest of the tank?
I think you shoud use the word pickup instead of intake, because it is quite confusing. I don't see the fuel pump pulling fuel into the cup, but the return line should probably be dumping into the "cup" to keep it somewhat full. Which way is the check vavle flowing, in or out of the cup?
What type of tank are you using and what pump?
What type of tank are you using and what pump?
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
The pump will not pull fuel into the cup just because it is near the check valve in the cup.
What are you planning on doing with the jeep? if it is just for the street it will be fine, my car has a cup/tray on the bottom of the tank and it just has a hole in the bottom center to let fuel in. It is only there to stop the fuel from sloshing to the side of the tank on hard turns/accel.
If you are looking for a hardcore offroad hillclimbing jeep you might need to modify the fuel system so that the pump will always be submerged even on long hills. The LS1 f-bodies have the pump pickup enclosed in a bucket that is filled by a venturi system on the fuel pump. This might be a good setup to put in. Or search for the system that someone used on a sandrail. I know he posted it on here. It had a low pressure pump that pushed fuel to a small external tank that was kept pressurized that way the main pump always had fuel....even when the car was on its roof.
What are you planning on doing with the jeep? if it is just for the street it will be fine, my car has a cup/tray on the bottom of the tank and it just has a hole in the bottom center to let fuel in. It is only there to stop the fuel from sloshing to the side of the tank on hard turns/accel.
If you are looking for a hardcore offroad hillclimbing jeep you might need to modify the fuel system so that the pump will always be submerged even on long hills. The LS1 f-bodies have the pump pickup enclosed in a bucket that is filled by a venturi system on the fuel pump. This might be a good setup to put in. Or search for the system that someone used on a sandrail. I know he posted it on here. It had a low pressure pump that pushed fuel to a small external tank that was kept pressurized that way the main pump always had fuel....even when the car was on its roof.
Thread Starter
Staging Lane
Joined: Feb 2006
Posts: 96
Likes: 0
From: Denver, CO
unfortunately I do offroad the vehicle, and in colorado, I'm on some steep stuff quite a bit. I'll see if I can find those other systems.
To answer the other qustions... the valve only lets the flow into the bottom of the cup. The return does dump into the top of the cup.
What I don't understand is when I hook it up the level never rises. It doesn't pull additional fuel into the bottom through the valve.
Thanks,
Mike
To answer the other qustions... the valve only lets the flow into the bottom of the cup. The return does dump into the top of the cup.
What I don't understand is when I hook it up the level never rises. It doesn't pull additional fuel into the bottom through the valve.
Thanks,
Mike
Last edited by Thumper33; Dec 14, 2006 at 12:32 AM.
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
What do you mean the level never rises? Do you mean that when you turn the pump on it drains the cup and the cup does not refill?
Or do you mean that once the pump is on the cup just stays at the same level of fuel as is in the tank?
Or do you mean that once the pump is on the cup just stays at the same level of fuel as is in the tank?
Thread Starter
Staging Lane
Joined: Feb 2006
Posts: 96
Likes: 0
From: Denver, CO
I'm testing it by putting it into the kitchen sink. The cup will immediately fill to the water level of the sink when I put it in there, and the level will stay there. I had expected to see the level rise as it pulls more water in through the valve in the bottom to feed the pump which has the inlet right next to the valve. I also figured that as soon as I lifted the setup out of the sink, that it wouldn't drain back out of the valve... and at least it doesn't do that. So ya... the cup stays at the same level as is in the tank.
I'm only trying to mimic the stock TJ setup by using most of it's parts with an aftermarket pump. I just expected the cup to fill up because I thought that it would draw more gas in through the valve. I guess it's not doing that. It won't draw more gas into the cup until the level of the cup is lower than the level in the tank. I guess that makes sense with the pump out of the picture. But I was hoping that the pump would put negative pressure on the valve to let it draw more in even above the level of the tank. Is this how the stock setup works?
I'm only trying to mimic the stock TJ setup by using most of it's parts with an aftermarket pump. I just expected the cup to fill up because I thought that it would draw more gas in through the valve. I guess it's not doing that. It won't draw more gas into the cup until the level of the cup is lower than the level in the tank. I guess that makes sense with the pump out of the picture. But I was hoping that the pump would put negative pressure on the valve to let it draw more in even above the level of the tank. Is this how the stock setup works?
Joined: Sep 2004
Posts: 3,148
Likes: 12
From: Downers Grove, IL
I don`t think it is possible to have the fuel pump pull extra fuel into the cup, at least not without some kind of venturi system. You should probably look into using a f-body fuel sending unit/pump since it has a venturi system to fill the cup that surrounds the fuel pump with extra fuel.
Either that or look into a setup like this. https://ls1tech.com/forums/conversions-swaps/265382-thoughts-tank-mods-run-fuel-injection.html
Either that or look into a setup like this. https://ls1tech.com/forums/conversions-swaps/265382-thoughts-tank-mods-run-fuel-injection.html
