Fuel Tank Balance Pipe

[rduart]

This question is for those of you who have plumbed a fuel tank balance pipe between the fuel tanks. I am wondering the routing of the balance pipe. I currently have a -10 fitting at the bottom front of each tank. I am thinking about running it forward to the firewall or under the engine. My engine is currently out of the car, and a friend has my engine lift. Normally I would drop the engine in to check. For an LS7 installation, is it possible to route the balance pipe under the engine, and would there be any issues. My frame has the original engine mounts. I purchased it before Ultima supported the LS7.

What did you guys do?

Please advise,

Randy

[srreck]

I have it running trought the bottom of the firewall. Easy to fit and to secure with P-clips.
Cheers,

[Steve_D]

My balance pipe runs along the bottom of the bulkhead.
I would not want it under the engine where it could get damaged by anything hitting the underside of the car.

I would also not want a -10 as the fuel will tend to surge back and forth.

Steve

[DHGTR]

my balance pipe also runs along the bottom of the bulkhead (sbc though).

[andygtt]

answer depends on the fuel system you are running.... if its the factory twin pump setup that draws from one tank at a time you dont want a larger balance pipe than a -6... if you doing your own fuel system then you can fit a -10 (I fitted a -12).

I routed mine along the rear bulkhead and made sure it was horizontal the whole way to avoid potential air locs when the tanks are balancing.

[GTWayne]

WARNING I have a -12 link pipe and it fills really slowly, I would use -16

[rduart]

Thank you all for your replies. Several different ideas here. Sounds like it might be more of an art then a science. My fuel system is of my own design. Its a twin pump system that has one (Holley) pump that pumps out of both tanks at the same time. This pump feeds a swirl pot. The swirl pot feeds a second (Holly efi) pump that supplies fuel to the fuel pressure regulator and the fuel rails. The fuel pressure regulator returns to the swirl pot and the swirl pot returns to both tanks.

My existing balance pipe has been built to run forward along the base of the firewall. Sounds like I should stick with this plan. As for the size of the balance pipe, my plan was to keep both tanks as level as possible and also to help with filling. Sounds like a -10 make not be large enough to help with the filling.

Thanks for all you help,

Randy

[crafty]

GTWayne said:

WARNING I have a -12 link pipe and it fills really slowly, I would use -16

I also have a -12 and it fills fine if you remove the both caps so that the tanks can breathe

[ROWDYRENAULT]

ok I don't want to get into a who's got the bigger pipe but I have a 1 inch line connecting the two tanks and the rest of my system is a bit like the original poster. One pump mounted lower than the tanks drafting out of both tanks at the same time, single line out of the pump to a big filter ( yes I know the argument for the filter being in front of the pump) out of the filter to a tee each side of the tee feeds one fuel rail, pressure regulator after the rails single return line off the regulator to one of the tanks. One fuel stock fuel level sensor in one tank. Works like a champ it was 103f yesterday in Chino which is 75 miles inland from were I live no fuss no fuel vapor lock fill the tank fom one side with very little problem. lee

[andygtt]

crafty said:

GTWayne said:

WARNING I have a -12 link pipe and it fills really slowly, I would use -16

I also have a -12 and it fills fine if you remove the both caps so that the tanks can breathe

I had -12 as well and it filled fine... i didnt even used to bother removing the other filler cap.

[V8 Vum]

I would LOVE to put a balance pipe in but I fear its too late for me as my tanks and sidepods are in!

..unless someone can tell me how I can do it?

cheers

keith

[Steve_D]

V8 Vum said:

I would LOVE to put a balance pipe in but I fear its too late for me as my tanks and sidepods are in!

..unless someone can tell me how I can do it?

cheers

keith

Both tanks have 3 ports.
The upper of the three can be linked across.
The two at the bottom are different. The front one can be linked using -6 the rear one has a pipe inside the tank that bends down right to the bottom of the tank so this should be used as the fuel pump pickup.

Steve