[Tom Vaught]

I have a 1965 GTO tank that was a Canada tank but not a Tanks inc piece that I also have. Had it for years.
Thinking about modding that tank with the "labrynth" sump in it.

I have access to a really good fabrication shop where they could bend the parts for the "labrynth" sump and the cover/pump mounting
parts. The "labrynth" to me would be easy if the shop had a proper bend roller then you just need to tack it together. .087 material would be really strong and .060 would be fine. The "wrap" at the bottom could have a couple of small plates tacked to help maintain the shape.
I would make the entrance so that it was facing similar to what he did except have the entrance face the right side of the car.
That way if you are going around a freeway exit ramp quickly the fuel would not run away from the "labrynth" entrance.
If the fuel is trying to flow into the entrance the height gets taller, if facing the way his was done the fuel would run away into the main parts of the tank and the sump fuel height would lower rapidly unless you had a lot of fuel in the tank.

Tom V.

[Tom Vaught]

Originally Posted by 68lemans462

The price of the tank is sumped tank is 239 for tank + sending unit $35 + pickup assembly $30.

I can get a standard replacement tank for about $100 delivered and the mods will cost a 12 pack and whatever other materials I'll need. Thus, the EFI tank is about 3x the cost if I dont include the time/effort to do this which I have NO problem with.

As previously mentioned I have a robbmc 1/2" pickup, mallory 140 with 1/2" lines from tank to pump, return regulator and 3/8" return line. The guy at tanks inc said their pickup assembly is 3/8" inside diameter.

What regulator do you have?
I have used the Holley 7/16" ball 12-704 Regulator and it always controlled pressure very well with the Mallory 140 pump.
The old Holley Blue and Red Regulators (and Pumps) were not set up to flow any real fuel. Grumpy needed two blue regulators (and Blue Pumps) on his 9 second Pro Stock Small Block Vega many years ago. Holley fixed that deal with the regulator below. PN 12-704

Tom V.

[68lemans462]

I use a Mallory 4309 regulator. Fuel system works well but tank must be 1/2 full at minimum at WOT. Any less than that and it'll run dry.

[HWYSTR455]

Originally Posted by 68lemans462

The price of the tank is sumped tank is 239 for tank + sending unit $35 + pickup assembly $30.

I can get a standard replacement tank for about $100 delivered and the mods will cost a 12 pack and whatever other materials I'll need. Thus, the EFI tank is about 3x the cost if I dont include the time/effort to do this which I have NO problem with.

As previously mentioned I have a robbmc 1/2" pickup, mallory 140 with 1/2" lines from tank to pump, return regulator and 3/8" return line. The guy at tanks inc said their pickup assembly is 3/8" inside diameter.

That's where it wasn't clear to me, that you already have the pump and regulator ("plan to use"). My comments/recommendation was to use an in tank pump, and their' pump assembly. That would eliminate the need for a pickup, but yes, you would still need a sender.

Also mentioned that although tech at Tanks says their' pickups and pump assemblies are 3/8", that's kinda true, it's 3/8 NTP. But the internal passages and tubing is the same as 1/2". Take a look at the pics attached where I mic'd them.

Once you total up the entire fuel system, in comparison, the gap in cost is much closer than you think. (and even closer depending on what kind of beer you drink!)

Curious how you make out though, I'm all about engineering solutions.

.

[73ta]

Holley fuel mat I think it's called. will cure the issues. No other alternatives other than an exspensive LS4 style pump, surge tank setup or sumped/baffled tank.

[torqhead]

Originally Posted by 68lemans462

Hey guys.. Ressurecting this thread in an effort to get a few more ideas before I build my tank. I have a new tank on the way and am using Dave (torqhead)'s ideas as inspiration. My father-in-law is an expert welder/fabricator and I'm going to commission him for help with this modification.

I've been looking at Dave's design (which obviously is effective) as well as another I found (https://ls1tech.com/forums/conversio...2-nova-32.html). I'm considering building the small "labrynth" as it looks easier/simpler than Dave's design to put together (less welding inside the tank,etc). Any comments as to a preference on this or Dave's design?

I'm also wondering which gauge of sheetmetal I'd use to build this? Does it need to be galvanized? The pictures of the "labrynth" modification appear to be aluminum? What is the best material to build the baffle out of that will hold up well inside the tank?

I'm planning to use my RobbMC 1/2" pickup with the tube extended fed by Mallory 140 and return regulator 1/2" and 3/8" return.

Wondering what will happen when the tank is low and you take a turn.

[242177P]

Originally Posted by 73ta

Holley fuel mat I think it's called. will cure the issues. No other alternatives other than an exspensive LS4 style pump, surge tank setup or sumped/baffled tank.

Hydramat. $699.95 for a 14" x 30"
https://www.summitracing.com/int/par...-110/overview/

[First Bird]

This was my alternative to sumping. I got this idea from the guys at an off-road 4x4 site. They have understandable issues with pickups uncovering.
It was fun but labor intensive. It works well and I have no fuel delivery issues on road courses.

The RobbMc 1/2" pickup feeds a Mallory 140 pump to a modded Q-Jet via 1/2" lines. Fuel returns from Mallory regulator via 3/8" lines. The Walbro pickups flow fuel but not air. That way when they are uncovered during fuel slosh, fuel continues to be picked up in the other corners.

To get the Genie in the bottle I cut a hole in the new stock tank. The "rubber" hose was carefully selected "immersion rated". After pickups were in, I installed the Jaz Aircraft style Fuel filler cap.

[Tom Vaught]

Say you are on a 45 degree bank angle (off road deal like you mentioned earlier).

Two of the pick-up are in "air" and two pick-ups are in "fuel".
How do the two pick-ups in the air keep the air from causing a lack of suction by the fuel pump or a massive air bubble in the fuel line?. CHECKVALVES??

Tom V.

[First Bird]

The pick ups work on a “wet screen” principle. Fuel flows through a mesh. If fuel stops moving thu the mesh, it stays in the mesh due to surface tension. Each opening in the mesh is clogged with fuel which prevents air from entering.

[Tom Vaught]

Learned something new, Makes sense, thanks.
Tom V.

[First Bird]

Stock Tank - $100
RobbMc sender - $150
4 Walbro PU's - $150
Gates hose - $70
Jay Fuel Cap - $80
Copper Tube - $20
Brass Fittings - $50

Total Cost about $650

[HWYSTR455]

These are the check valves I used when I had the one tank made, used a sump which was just a box, the check valves along the floor, had 2 'wings' for baffles to help prevent slosh, and the return dumped into the sump.

They make trap doors too.

They were much less expensive back then though.

.

[HWYSTR455]

The one I did was based off this design, but I need a larger capacity surge/sump.

You can also combine those with corner collectors if you choose.

.