How to make a sumped tank?

[t72ss402]

Ok so I am still looking for the best option for a fuel tank for my 72 chevelle. I plan on running a ls6 motor.

So my question is what is the best way about sumping a stock tank? I am buying a new tank anyway so welding a sump on would be easy.

What is the best kit to use?

Thanks Tim.

[armourmark]

bump, I'm curious what others will say too. There is some good info on this over on ls1tech.com using a ford pump.

[garys 68]

I just put an LS motor in 72 cutlass. I bounght a 96 caprice tank. It fits and already has a sump. You'll need to upgrade to an intank walbro 255 pump. Total cost about $250. About the price of a new unsumped tank. Btw, the fuel level sender works with a stock gauge too.

[t72ss402]

I am going with a stock tank that I am installing a comp. engineering sump on, I am going to go with an external fuel pump, with a filter before and filter after. I have documented it step by step and will post up the pics after I finish it.

Tim.

[Skip Fix]

For my Camaro I had a shop make a sump out of stainless like the CE one. All of the aftermarket ones are plain steel and I worry about the moisture in today's ethanol gas rusting it. Drilled only about seven 1/2" holes over it to act as baffling. Welded return and vent bungs up top.

[t72ss402]

Skip your tank looks good. Really darn close to what I am ending up with. From what I understand as long as you put some sealer in your tank and let it dry then it should be ok and not rust. We will see.

Tim.

[parsonsj]

If you use the right fuel pump, you don't need a sumped tank:

https://www.pro-touring.com/showthre...nova+fuel+tank

[Skip Fix]

I guess I'm not understanding what is in that recessed tank in the link. Most factory FI tanks have some kind of in tank sump so in a turn the pickup doesn't suck air in a turn/braking/accelerating if it gets uncovered. I'm not seeing it on that fuel pump deal and no surge tank is mentioned.Looks like it is just an electronic module to match engine demand and pump output to me.

My SS sump welded on and bungs welded was less than $200 new tank about $150

[t72ss402]

John, trust me I looked at that for a real long time. Like Skip I will have less than $200 in my tank and it is all new, not saying cheaper is always better but I get the thrill that if anyone asked me where I got my tank I can tell them I customized it. I guess kinda of a bragging rights thing. Since you only have a Camaro tank at this time you could always use my car to mock up one for a Chevelle. LOL.

Tim.

[parsonsj]

Tim, I've no financial interest in that setup. That's Carl Casanova's brain child, and one I'll be using on Unfair.

My actual point is that instead of thinking about modifying the bottom of the tank and going with a marginal setup using an external pump and mechanical regulator, why not consider modifying the top of your tank, and going with Carl's setup. It's just better in every way: quieter, less heat transfer to the tank, perfect fuel pressure, and it uses OEM components that should outlast those external components several times over.

jp

[parsonsj]

I guess I'm not understanding what is in that recessed tank in the link. Most factory FI tanks have some kind of in tank sump so in a turn the pickup doesn't suck air in a turn/braking/accelerating if it gets uncovered. I'm not seeing it on that fuel pump deal and no surge tank is mentioned.Looks like it is just an electronic module to match engine demand and pump output to me.

The Camaro/CTS-V pump setup has it's own internal sump, internal regulator, and controller. Take your basic $150 tank, and modify the top of it with this setup, and you're golden.

Carl has tested this with less than 2 gallons in the tank on an autocross. It worked with no loss of pressure, no cavitation, no hiccups at any time. After finishing his day at the track, he drove it to a gas station with the fuel gauge dead on empty.

I know I sound like a fanboy of Carl's setup, but that's because I lived the sumped tank/external pump/mechanical regulator story with II Much, and it's a real drag if you are used to late model cars and their highly engineered fuel systems.

jp

[garys 68]

Since the late 90s GM has been using a single pump/sump/sender module in their tanks that dont require any kind of additional sump built into the tank. The pump has 2 inlets, one that sucks from the tank by venturi effect and only fills the sump can, and another that sucks from inside the sump and supplies the engine. In addition, there's a one way valve that allows fuel to flow in.
You can use a 99-02 f body (returnless) or corvette or truck pump/sump assembly (with return) on any LS motor and they'll operate just like factory. There are a couple places that sell the mounting ring to attach to the tank.
The problem comes up with the A body chevells/GTO/cutlass the original post was referring to. Their tank is too shallow to fit a standard GM pump assembly. The earlier CTS-V pump assemblies look to be the shortest and might fit, but they're pretty expensive.
The bottom sumps like you have work great unless you have a clearance issue (my 68 corvette mounts the spare there), or it's a used tank and no one wants to weld on it.
For my 72 cutlass I went with a 96 caprice tank since it's about the same dimensions as the A body tank and has a built in sump. I did upgrade the pump to an intank walbro 255.

[t72ss402]

John, I appologize for some reason I thought you carried this setup, my bad for not researching. LOL. It really sounds like a great piece but as Gary just posted I am conserned about how shallow the tank is.

Gary I looked at a pic of the impala/caprice tank on a chevelle, and looked like it sat really low, almost as kinda of a eye sore look. I know that the sump will hang down but it almost has that cool factore that when someone looks at your car from behind they say "huh wonder what else he has done to the car". Just kinda my way of thinking about it I guess.

Thanks Tim.

[parsonsj]

John, I appologize for some reason I thought you carried this setup, my bad for not researching. LOL. It really sounds like a great piece but as Gary just posted I am conserned about how shallow the tank is.

No worries. I wish I'd thought of it.

[Twentyover]

John-

I looked at the link and it appears this is for aftermarket SS tanks, not the terne coated steel tank I have. Am I reading it wrong?

[parsonsj]

Greg,
The tank material doesn't matter. You can weld Carl's pump insert to either a SS or a mild steel tank. In either case, quality welding is a must, though it is true that welding SS to SS is a bit easier than to mild steel. However, any decent welder can do either one. The real problem is tank depth: the setup requires 8.25 inches.

Carl is even working on an aluminum insert for some of us for our own custom aluminum tanks.

[CarlC]

If your tank is at least 7" tall one of the later model fuel modules can be made to fit.

4th-gen units are too tall unless the trunk floor section is raised or a deep sump added to the tank. Here's one that is mounted in a 1st-gen tank that was based off of my proof-of-concept model.



More info on that tank can be found here https://www.pro-touring.com/showthre...tra-tank/page3

[Twentyover]

I guess therein (for me) lies the rub. The car is a mid-70's European Ford (Capri- it was my first car out of college). The tank is 6.25 inches fron the top seam to the lowest part of the tank, with maybe another inch at the top of the ribbed section of the tank top to the seam. Looks like you need an inch of depth or so for the depession cutout- that would set me right on the seam. The tank fits under the spare tire well, so must be shallow (I'm not going to a fuel cell- although I may be talked into a well cell for track days.) There is a raised section on the passenger (fill) side about 14" height but a small area (Naybe 10' wide by the length of the tank.) The vent/rollover valve and fill pipe live on this surface.

So am I screwed and need a sump or is there something else out there?

[t72ss402]

Here are some pics of my finished tank.

[t72ss402]

Here are some better pics. I have more I just need to edit them to fit.