Fuel Tank Pick Up Problem

[w6df]

I am using a custom built 15 gal aluminum tank with -8 outlet at the bottom rear of the tank. The BG fuel pump is mounted level with the 10" -8 outlet on the "bottom" of the tank(flush). Every once and a while the pressure drops to ZERO and I have to recycle the pump to get the 8psi. I changed the pump and everything is clean and new. Should I suck the fuel from the top through a -8 aluminum pipe or from the bottom (vortex problem)??
Jim

[lineslinger]

Do you know the interior set up of your tank? Is the pickup point in a baffled chamber or is it just an open area, with no enclosure to contain fuel for pump demands. Another possibility could be the lack of a properly vented fuel tank, losing your pump prime due to a vacum building within the tank
As your fuel levels get lower you could lose your pump prime due to sloshing during braking or cornering, or as you thought vortexing down through the pickup and allowing air into the pump thus losing your prime. I am not familiar with the construction of an EM fuel tank but you may want to contact the dealer and hear what they have to say.

[wtm442]

Originally Posted by w6df

Should I suck the fuel from the top through a -8 aluminum pipe or from the bottom (vortex problem)??
Jim

Best location for electric fuel pump is slighly below the tank outlet on the bottom, and behind the tank.

[Morris]

Go to this link read pages 23 and 24.....and you'll see how to fix you issue....

http://kmsac.com/index.php?option=co...&topic=278.330

Morris

[w6df]

The confiq on the tank is "L" shaped view from the sides, that is 8" at the pick up end (back) and 18" at the front. The tank has 4 baffles but the -8, 90degree fitting on the bottom corner of the tank has a 8x8" x 8" clear area above (no vortex baffle). I think the pump is creating a vertical vortex and sucking air at times. I am going to pull the tank and make a new fitting (-10) on the top with the pick up tube facing downward 1" off the bottom??

[Tom Wells]

Hi w6df,

Here are a few photos of my gas tank sump:

http://www.firstcoastcobraclub.com/g...g2_itemId=2120

It was added when an ordinary Interstate highway high speed turn would cause the fuel pressure to go away. This is especially bad with fuel injection, because if it happens while you have the power on, it will lean out and hasten the destruction of the engine

At first I tried a 3/4" ID tube lying flat in the bottom of the tank with lots of holes and relying on the E-M internal tank baffles to provide the fuel when subjecting the tank to some G-forces. It didn't work.

The outlet is now at the bottom front of the sump. I think there's a pretty good baffle at the top of the box but could not verify. It works well in two dimensions! No problems at the track.

Tom

[w6df]

I pulled the tank this weekend. Off to the machine shop to rework the pick up and change from -6 to -10. Dash 6, no wonder there is a problem!!!! I am going to weld a "U" on the end of the -10, 90 degree elbow and point the inlet at the bottom of the tank to reduce the vortex. I think the smaller the inlet the more pressure for a given volume casuing a vortex generator (air bubbles). I will keep the forum posted.
Jim
PS: The inlet to the BG pump is also -10

[w6df]

Here is what I am setting up for next summer:

http://www.barrygrant.com/pages/sema06.aspx

[Tom Wells]

If you're gonna feed that thing uninterruptedly, you need something like this:

http://www.aeromotiveinc.com/pdetail.php?prod=66

[bkozlow]

Does anyone know where to get those finger strainers as shown in the Kirkman site Morris referrenced?

Bill K

[Morris]

Bill

Go to Aircraft Spruce ...they are about $5.00 each......

Morris

[w6df]

Well, The -10 did the trick. No problems so far with loss of pressure. After I re-installed the tank with the new -10 inlet, I had to reduce the pressure regulator from 10.5psi to 8.5psi. It's working!!