Surge tank - Fuel starve solutions?
CJM is supostodly making their in tank solution for me soon. Much better piece of mind to have all fuel related pumps in the tank and behind a firewall. Shoot them an email if your interested.
The purpose of the jet-pump is that it is a venturi device with no moving parts and no wear and requires no cooling or lubrication.
The pump resides on one side of the tank as you know. The jet pump will transfer fuel faster than the engine consumes it in the overwhelming majority of operating conditions. This means that the driver side of the tank will empty before the passenger side begins to lower past the dividing wall even though the fuel pump is on the passenger side.
Until the tank is empty, the fuel pump remains wet (fuel starvation due to slosh during aggressive maneuvers excluded). Fuel slosh will be recovered by the jet pump at a rate that exceeds engine consumption, which is why starvation does not occur under normal driving conditions.
I could write a novel here with all the various scenarios and different ways you could choose to try the plumbing for your system.. but there is one entirely inevitable issue that is the reason why putting a fuel pump on each side of the tank is never the end-all solution for the countless track cars of various make and model that offer fuel tank openings on both sides of the tank.... pumps will be running dry. A factory fuel system Z experiences starvation because a pump runs dry, and putting a pump on the other side well take car of the drop in fuel pressure, but it doesnt stop the pump from running dry... now they just take turns running dry as you slosh the fuel back and forth.
The quickest way to kill a fuel pump? Run it dry.
You keep one pump in the tank, and you do everything you can to keep that pump wet.. rather then saying "the hell with that pump" and letting it starve and getting your fuel pressure from multiple sources so that you never have to depend on 1, you want to keep the pump that you do have in there wet (and alive). This is what a jet pump does. Its like having a fuel pump on the other side of the tank, but instead of feeding the engine, it feeds the primary fuel pump to keep it wet. Since it itself will inevitable starve very often, they use a venturi with no moving parts rather than a small electric fuel pump (which would, trust me, cost less in the end as the engineering and tool building for injection molded jet pumps is a big hassle... a small $15 electric pump would be much easier on them if it was a reliable system).
The pump resides on one side of the tank as you know. The jet pump will transfer fuel faster than the engine consumes it in the overwhelming majority of operating conditions. This means that the driver side of the tank will empty before the passenger side begins to lower past the dividing wall even though the fuel pump is on the passenger side.
Until the tank is empty, the fuel pump remains wet (fuel starvation due to slosh during aggressive maneuvers excluded). Fuel slosh will be recovered by the jet pump at a rate that exceeds engine consumption, which is why starvation does not occur under normal driving conditions.
I could write a novel here with all the various scenarios and different ways you could choose to try the plumbing for your system.. but there is one entirely inevitable issue that is the reason why putting a fuel pump on each side of the tank is never the end-all solution for the countless track cars of various make and model that offer fuel tank openings on both sides of the tank.... pumps will be running dry. A factory fuel system Z experiences starvation because a pump runs dry, and putting a pump on the other side well take car of the drop in fuel pressure, but it doesnt stop the pump from running dry... now they just take turns running dry as you slosh the fuel back and forth.
The quickest way to kill a fuel pump? Run it dry.
You keep one pump in the tank, and you do everything you can to keep that pump wet.. rather then saying "the hell with that pump" and letting it starve and getting your fuel pressure from multiple sources so that you never have to depend on 1, you want to keep the pump that you do have in there wet (and alive). This is what a jet pump does. Its like having a fuel pump on the other side of the tank, but instead of feeding the engine, it feeds the primary fuel pump to keep it wet. Since it itself will inevitable starve very often, they use a venturi with no moving parts rather than a small electric fuel pump (which would, trust me, cost less in the end as the engineering and tool building for injection molded jet pumps is a big hassle... a small $15 electric pump would be much easier on them if it was a reliable system).
Last edited by phunk2; Jan 7, 2016 at 07:42 AM.
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