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.