fuel tank pickups for efi conversion

so, im planning the tank end of things now for my 70 duster EFI swap. using an external pump.

wwas thinking about how to utilize the stock tank, and keep fuel being picked up well.

struck on the idea of using (4) 6AN bulkhead fittings, one in each corner of the tank on the tank floor. running these in series, connected with t-fittings and hard line. then, take the outputs of both sides, into a third t fitting, and into my frame mounted pump.

this seems like a great idea. only concerns i have are:

1. sucking air. path of least resistance and all that, would mean that the one pickup thats uncovered would be the only one drawing to the pump, correct
2. sealing the bulkhead fittings. fairly new and shiny metal tank. im worried about fuel seepage, etc. no drips/leaks is my motto when it comes to fuel
3. making the fuel turn90 coming out of the tank. no room on the sides of the tank for the fittings, so they will have to go in the bottom. dont want them getting ripped off by road debris, so id like to tcuk everything tight to the tank. dont kow how tight i can get with tubing without kinking, and 90 fittings add like 2 inches to the length.

the other option i thought of was those walbro pickup screens they sell to the rock crawlers, but i have no way of getting them into the back corners of the tank, and no idea how to secure them. anyone have experience with these in a stock tank install?

so, generally, im looking for a cheap way to make a starvation free pickup system. rock valley wants 800 bucks for a baffled, in tank pump setup. ny budget for the tank is more like 200. theres no room between the top or sides of the tank and other stuff, and its a used tank, so welding it out.

what say ye, GRM collective?

michaekl

How about a swinging pickup setup. A GRM style could be a hose with a pickup on the end that moves along with the gas. Here is one: http://www.autoperformanceengineering.com/html/pickups.html

You might google for "swirl pot". Basically, you add a second small tank, too small for fuel to get away from its pickup. You feed this from the main tank, and it provides a buffer so that if you draw air from the main tank for a few seconds, it won't starve the high-pressure pickup.

I'd sooner go with the swirl pot than the multiple pick-up points. It seems as if you get one of them to start picking up air and you lose the fuel flow. Although if the car isn't being subject to hard cornering, if it's more of a cruiser or drag car, I'd just go with a single pump on the stock pick up.

I built something like a swirl pot for the Lemons car for the last race out of a fuel filter. We were having fuel starve problems below 3/8 of a tank. Worked like a charm until the tank got below 1/8 tank.

The tank pump feeds the filter. In one port and returns out of another. The EFI pump pulls off a pickup I installed at the bottom of the filter and returns back to the tank.

It saved us trying to baffle or modify the stock tank.

Some people just weld these underneath the stock fuel tank with a screen in place to keep the big junk out. http://www.jegs.com/i/Jegster/550/40757/10002/-1?parentProductId=747210

problem with a swirl pot is this: theres no room, except underhood. and thats getting more and more cramped every day, and will be even moreso when i stuff a centrifugal on it.

the swinging pickup idea is using the screens i was talking about. just unsure how to plumb them into the tank.

the car gets autocrossed, cross countried, drag raced, and daily driven. so my fuel system has to cope with these demands.

rock valley does make a baffled, in tank pumped tank, but at 800 plus tax and shipping. im trying to find something considerably cheaoer than this, that will be effective.

i do not have the capability to weld a gas tank, nor do i know anyone brave enough to do it.

hopefully i didnt miss anyone. if theres ways around what im describing here, let me know. id appreciate it.

regulator will be a c5 corvette unit that returns fuel to the tank.

michael

how about those new fangled pickups that came out within the last few years that don't suck air even when they aren't submerged in fuel? something about the surface tension of the fuel forms an airtight seal when there isn't actual fuel flow or something like that.. put one on each side of the tank and T them into a common line and you should be good to go..

From what you are saying, I think your best bet is the swinging pickup idea. Check on off-roaders forums for more details. They use those setups often.

The multi pick-ups idea is just a leak waiting to happen. Most gas tank walls are not really straight so your bulkhead fittings would probably leak. Plus it would require a lot of fittings which are all potential leak sources. Plus all those fittings would be hanging pretty low and exposed to being ripped off (scary!).

And welding a used gas tank is not that scary. I have done it on a motorcycle tank. It was taken off the bike, all fitting were removed to flush all the gas, then I rinse it with water and left it outside for a week to make sure that all possible gas vapor could escape. Didn't have a problem to weld but YMMV

Dusterbd13 wrote: problem with a swirl pot is this: theres no room, except underhood. and thats getting more and more cramped every day, and will be even moreso when i stuff a centrifugal on it.

Not sure about the later A-bodies, but on my Dart, I managed to fit a swirl pot to the floorboard where it slopes up for the back seat, in front of the rear axle.

Don't let the fuel get below about 1/8 tank?

That's the way I did it when I converted my carbureted car to EFI. Pickup is on the left side, it's only a problem with extended left-hand corners below 1/4 tank.

Alternatively, get a fuel pump box for a late 80's Golf/Jetta. It's small, holds a liter of gasoline, and the ones from a CIS car will have a pump that will supply way more fuel than you'll need. (Something like 400hp worth @ 42psi) A generic anything-pump feeds it from the main fuel tank and the return from the engine also dumps into it, so even if the tank is sucking air, you still have a liter's worth of fuel before you have problems.