Modify gas tank for EFI

Discussion in 'Classic Mustang Specific Tech' started by 68converted, Mar 24, 2007.

  1. Here is the plan. I cut a hole in the top of the tank. I plan to add a length of sheet metal that is 6 inches tall by two feet. I plan to drill large and small holes the entire length of the strip. I want to weld the strip to the bottom of the tank in a semi circle around where the pick up will be.

    I am hoping that this will serve to keep enough fuel around the pickup during hard cornering and keep the pump from starving.

    Any ideas??? Is there something I need to do to the new metal and the welds to stave off corrosion?
  2. check out They have an install on an in tank fuel pump on a stock tank. The pump/sump kit is sold by It doesn't have a real large sump for the fuel to sit in so I don't know if it will do real well in a autocross/racing situation, but it does look like a nice way to keep a stock appearance and still have an in tank pump. I suppose you could weld more baffling onto their kit if the need should arise.
  3. That is and option, but I decided not to do the in tank pump. I have a sweet external 155lph bosche pump that I got for free. I am trying to save some money. I played around with some thin metal taped to the bottom of a wash basin to see how different arrangments would work.

    I came to the conclusion that I have to have less holes and more baffles to allow the fuel to be held in place, but also allow the area of the pump to quickly fill (level) with fuel when the car comes out of the turn.

    Kind of cool to play around with various ideas. My 8 year old son came up with the idea to place straight lengths at angles (wider at the pickup, and narrow to the back of the tank) with space on the front side to allow fuel to rapidly flow back in. Love the open minded nature of kids!!!
  4. Good idea using the tub to experiment. Post some pics when you come up with the final design as I would be interested on doing something similar. I have heard that the baffling is the most important and the hole size and location is not as important as long as it will keep the fuel level and in the sump.
  5. Hello,

    i don´t sump my tank. I installed a catch tank in the trunk and feed it with a low pressure high volume facet pump. I installed a second pickup in the trunk floor, but it is not needed. A high volume (255 l/h) high pressure bosch pump take the fuel from this catch tank. The return line goes in the catch tank too. The overflow line from the catch tank goes in the original tank. So i can drive my tank empty without fuel starvation.


  6. I have looked at probablly 20 EFI conversions.

    There are four ways to do it that seem to work okay.

    1) Buy the parts from Ron Morris and use the stock tank. About $350. Problems: pickup under 1/4 tank if you plan on driving the car hard in corners.

    2) Build your own tank/modify the stock one for an in tank pump and sump. About $450. Problems: most of us don't weld too good. Get ready to do it a couple of times before you get the leaks out. Who knows on the baffling.

    3) Do what Markus did. About $1000. Problems: Lots of parts to pay for, lots of parts to work together (fail), lots of parts to mount, just lots and lots of parts.

    4) Buy a stainless tank from Ricks with a sender, an internal pump, and install it. About $1100. Problems: $1100.

    I'm gonna get my wallet out for mine I think.
  7. aeromotive is supposed to have a baffled tank out now that's about $450, it's in the latest Year One catalog but i haven't been able to find it on aeromotive's website.
  8. » Performance, » Aeromotive

    Fuel Tanks
    Text only view | Thumbnail view | Picture view 1 | Picture view 2 | Picture view 3
    Part # Description Price Add to Cart
    AE18619 Fuel tank with sump and baffle for 1969 models.
    AE18620 Fuel tank with sump and baffle for 1970 models.
  9. A buddy of mine came by today as I was working on the tank. He said he had a new in-tank pump he said was a bosche high volume. He said it looked exactly like the mustang pickup. He is going to bring it by this week. He wants to trade me for external unit I have. Nice deal I think, if it fits.

    I think the in-tank, with the baffles will work fine, and I don't believe I will need to sump it. (??????) we will see. This just seems like it will be a cleaner setup.
  10. My concern is I won't get past tech with a system like yours for OT events, which I plan on doing.

    This is what I am doing for the baffles. Strategic holes are cut throughout the runs w/ larger holes where gas would pool. The rectangle at the top is the cut out I made for access, which will be welded back up when the baffles are finished. The circle is the filler hole.

    Now the question that really matters. What do I treat the baffles and the spots where they are welded to the tank?

    Attached Files:

  12. Markus that is a really nice and clean setup thanks for posting all the good pics. Much props. ;)
  13. 68 does it have to have a sump or is that just to try to make it work? Why not just grab a EFI fuel tank outta the junkyard? *Confused*
  14. Many have tried, none that I know have succeeded finding a swapout tank. I don't want to modify the trunk. Expense is also a reason to do this. The tank is brand new, as the old one had some major rust.
  15. I spend three weekends in pick n pull looking for just that. No luck. Most OE fuel tanks are under the rear seat area and GOOFY shaped lookin' things.

    If I didn't have 300hp now I'd use a F-150 frame mounted pump and fish the return line back through the OE sending unit.
  16. EFI Tank

    Here is another idea.


    More info is found on my web page.

    Attached Files:

  17. I have decided on the baffle position. Can anyone tell me how to treat the new metal and the spot welds? Is it even needed?
  18. I checked out the eastwood stuff... my tank is brand new. Is the metal in these tanks even treated to begin with? It does not look like it is coated... anyone? would I be fine just leaving it untreated?

    How do I wash the tank out to get the welding particles and metal dust from when I cut the access panel. (without starting the rust process ie. no water?)