Hartstoc
Well Known Member
I’m deleting the engine driven fuel pump from my RV, and the quest for a reliable, appropriately sized, power-efficient electric fuel pump suitable for full-time operation with my Bendix-type Injected 180 HP Lyc 360 generated a lot of discussion is a recent thread here. (Link at bottom). Most electric pumps used today are grossly excessive and waste a huge portion of the power they use by endlessly recirculating most of the fuel they pump(ideally through return lines to the tank in use.) That is bad news if you are running on battery power after an alternator failure!
I concluded that performance and efficiency data from the pump producers was not accurate or reliable enough to draw meaningful conclusions from, so I would have to do in-depth testing on my own within the range of pressures I’ll be using. I’ve decided to bench test and then autopsy three pumps, the Delphi supplied by Airflow Performance, the lower pressure Walbro GSL395, and the mid-pressure Walbro GSL414 suggested by Ross Farnham. I hold great hope that the 414 will be the winner here.
Here is the setup I built for bench-testing output and electrical consumption of electric fuel pumps operating at various pressure levels. In order to make it as real-world as possible, it purposely includes enough filters, fittings, bends curves and total lift to roughly simulate the friction losses that will be encountered in the actual installation. None of the hardware-store components you see are for installation in an aircraft, and my own final installation will include dual pumps , dual external relief and check valves, and dual electrical sources for each pump.
The three tubes seen lower-center include the pickup tube and return lines from the relief valve and from the “net output restrictor” will rest inside a 5-gallon pail of stoddard solvent. Both of these have 3-way brass valves so their flow can be individually and fully diverted to a separate graduated flask for measuring flow rates with a stopwatch. At the top you can see the battery, switch, shunt, V/A meter, and pressure gauge. The two in-line ball valves will allow closing or restricting flow through the relief valve or to the “engine”
Operating the pump with the output line closed and the relief valve line open and shunted to the measuring flask will allow measurement of relief valve set-point pressure, electrical load, and maximum flow available at that pressure. Operating it with the relief valve return line closed off, and the main output line shunted to the measuring flask, the inline valve can be used to dial in any pressure desired and measurement of current, pressure, and flow rate at that pressure simultaneously.
The Delphi pump supplied by Airflow Performance is shown installed here and will be the first tested. You can see the Walbro GSL414 banjo- mounted to another relief valve package in the lower left. Testing it and the Walbro GSL395 will require a few mods to this rig as their banjo mounts have to be inserted from the opposite side of the relief valve assembly.
I’m awaiting delivery of a safe solvent for use in testing, and will publish results and photos of the pump’s internals here soon. But any suggestions or comments on this setup or methodology would be welcome.- Otis
Link to priorthread: http://www.vansairforce.com/community/showthread.php?t=167848&highlight=Anatomy
I concluded that performance and efficiency data from the pump producers was not accurate or reliable enough to draw meaningful conclusions from, so I would have to do in-depth testing on my own within the range of pressures I’ll be using. I’ve decided to bench test and then autopsy three pumps, the Delphi supplied by Airflow Performance, the lower pressure Walbro GSL395, and the mid-pressure Walbro GSL414 suggested by Ross Farnham. I hold great hope that the 414 will be the winner here.
Here is the setup I built for bench-testing output and electrical consumption of electric fuel pumps operating at various pressure levels. In order to make it as real-world as possible, it purposely includes enough filters, fittings, bends curves and total lift to roughly simulate the friction losses that will be encountered in the actual installation. None of the hardware-store components you see are for installation in an aircraft, and my own final installation will include dual pumps , dual external relief and check valves, and dual electrical sources for each pump.
The three tubes seen lower-center include the pickup tube and return lines from the relief valve and from the “net output restrictor” will rest inside a 5-gallon pail of stoddard solvent. Both of these have 3-way brass valves so their flow can be individually and fully diverted to a separate graduated flask for measuring flow rates with a stopwatch. At the top you can see the battery, switch, shunt, V/A meter, and pressure gauge. The two in-line ball valves will allow closing or restricting flow through the relief valve or to the “engine”
Operating the pump with the output line closed and the relief valve line open and shunted to the measuring flask will allow measurement of relief valve set-point pressure, electrical load, and maximum flow available at that pressure. Operating it with the relief valve return line closed off, and the main output line shunted to the measuring flask, the inline valve can be used to dial in any pressure desired and measurement of current, pressure, and flow rate at that pressure simultaneously.
The Delphi pump supplied by Airflow Performance is shown installed here and will be the first tested. You can see the Walbro GSL414 banjo- mounted to another relief valve package in the lower left. Testing it and the Walbro GSL395 will require a few mods to this rig as their banjo mounts have to be inserted from the opposite side of the relief valve assembly.
I’m awaiting delivery of a safe solvent for use in testing, and will publish results and photos of the pump’s internals here soon. But any suggestions or comments on this setup or methodology would be welcome.- Otis
Link to priorthread: http://www.vansairforce.com/community/showthread.php?t=167848&highlight=Anatomy
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