EFI tech video: How baffled and sumped fuel tanks work

[MadScientistMat]

Baffles or sumps are very common on EFI installations to limit hiccups at low fuel levels. I've made a quick (under 2 minutes) video where I demonstrate how they work and how you can test out your own ideas.

 

[jbc426]

Nice job on the video. Tanks have come a long way in the last 10 years. Some of the factory style drop-in pump assemblies are great as well, but require a large hole be cut in the tank and they can protrude above the tank significantly.

Before the availability of inexpensive baffled fuel tanks and the added complexity of welding a sump in a stock tank, I've began using a surge tank mounted in the front of the car and a stock tank with a drop-in fuel pump with a Holley Hydramat pick-up. The Hydramat is almost like alien technology, as only one part of it will wick straight fuel up from the tank.

This system supplies air free fuel even down to the last few gallons in the tank, and circulates fuel between the tank and the surge tank at near "0" psi at high volume. The high pressure EFI circuit circulates the fuel through the fuel rails an regulator in & out of the surge tank. Any bubbles or captured air is quickly purged from the surge tank and sent back to the tank with the returning fuel.

 

[MadScientistMat]

I had a surge tank earlier, but replaced it with a sumped fuel system and single pump when the tank became rusted out. Surge tanks can work great if you don't want to modify the tank or have really wild fuel slosh - the drift guys seem to really like them.

I've seen Hydramat demos where they have just one corner touching fuel and they keep pumping. It's wild. It is also a wear item and rather expensive, but if you can afford a giant sheet dropped into your tank, it's definitely another option.

 

[AndyF]

I built a custom tank for my Duster project. Fitted it with baffles as well as a one gallon sump in the very bottom where the pickup was located.

 

[jbc426]

I built a custom tank for my Duster project. Fitted it with baffles as well as a one gallon sump in the very bottom where the pickup was located.

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Now, that's nice work on a well-designed tank. Beautiful!

 

[MadScientistMat]

Thanks for posting that example, Andy! Are the spots at the bottom of the baffles cutouts, or are they tack welds and fuel can slowly flow under the non welded part?

 

[Map63Vette]

I've seen Hydramat demos where they have just one corner touching fuel and they keep pumping. It's wild. It is also a wear item and rather expensive, but if you can afford a giant sheet dropped into your tank, it's definitely another option.

Really? What's the lifespan on them? Would it be equivalent to something like a typical fuel bladder that you might find on a race car? I had debated tossing one in my tank at one point as I just liked the idea of being able to use as much capacity as possible if needed, but never knew they wore out.

 

[MadScientistMat]

Really? What's the lifespan on them? Would it be equivalent to something like a typical fuel bladder that you might find on a race car? I had debated tossing one in my tank at one point as I just liked the idea of being able to use as much capacity as possible if needed, but never knew they wore out.

5-10 years, according to Holley's instructions.

 

[DionR]

I posted this in another thread but since we are talking about tanks and such, I thought I would repost it.

I bought a Gen5 Camaro pump with the basket and had a friend weld the top of GTO tank into a new A-Body tank.

The GM pump works like a surge tank in that it has a basket that surrounds the pump and a suction nozzle that fills the basket. In theory, shouldn't have any issues with slosh even at almost empty as the suction pump side of the setup keeps the basket overflowing with fuel.

Only downside I see is that I lost a little fuel capacity. And there is more fabrication than buying a Tanks Inc setup or something similar.

Note that I didn't have to recess the pump like I did, I just didn't want to space the tank down or cut a hole in the floor of the car.

Here is an article on it - Fuel Modules - VaporWorx

And a visual:



Also, the Camaro pump requires an adapter to run a FPR - Aeromotive. The valve in the basket is a pressure relief not a FPR since the pump is PWM in the Camaro.

 

[MadScientistMat]

That's pretty clever - using the suction side of the fuel pump to drive a jet pump, letting you effectively build a surge tank system with only one electric pump.

 

[goldduster318]

I did this in 2015 when the Aeromotive Phantom was about the only thing you could get. I'm sure the foam won't last forever, but there is also a rubber bucket outside of it. The hole is lifted by 1x1 square tube and has a piece of sheet metal over it. I can service the pump from inside the trunk and its almost unnoticeable otherwise. I made a dent in the tank to pass the AN hose past so the tank sits exactly how a stock one does.