T' EFI return line into pump supply

[CochinoFilipino]

Generally you don't want to recirculate the fuel. After running through the system it gets hot and the mixture is well cavitated (full of little bubbles).

I was thinking that the fuel lines might provide enough cooling. And I can see air bubbles being created in 68converted's diagram but with my idea I don't see where any air could enter the system.

 

[red65]

I was thinking that the fuel lines might provide enough cooling. And I can see air bubbles being created in 68converted's diagram but with my idea I don't see where any air could enter the system.

Without a baffled tank, you'll pull air into the pump whenever the tank gets low and the remaining fuel sloshes enough to uncover the pickup. You'll pull in air bubbles, and they'll never leave until they find their way through the injectors; you won't like the way it's running while that happens, by the way. Recirculating that air bubble a dozen times while it finds its way out isn't going to make the problem any better.

When I first did the EFI conversion in my '65 the fuel pickup would start uncovering at something less than 1/4 tank for regular street driving, but it would happen at around 1/2 tank at the track (the kind with lots of curves). It really sucks to end or delay a track day becuase you're functionally out of gas, even though you're carrying half a tank. I wound up fabricating a stainless steel header tank and plumbing a low pressure pump to keep in fed - lots of people have done something similar. If done well, it completely solves the problem.

 

[CochinoFilipino]

Without a baffled tank, you'll pull air into the pump whenever the tank gets low and the remaining fuel sloshes enough to uncover the pickup.

That's true with a regular EFI system where all of the fuel moved by the pump is being dumped into the tank and then is sucked through the pick-up. And I understand this.

But with my idea the return line would be feeding the pump, not dumping into the tank. Only the amount of fuel being consumed by the engine would need to come from the pick-up in the tank. That would be very little. I doubt that much, if any, air would be sucked in.

I'll have to try it and let everyone know. But don't hold your breath. It'll be a while.

 

[Hack]

I'll throw in my plans as well... on my car I had planned to move the gas cap ala the dodge charger to the upper left fender. Flush mount aircraft style filler recessed into the panel...

Anyways.. I did some looking around and found a tank out of a early 90s ford van that was just about the right size as our tank, and was for EFI. I have not seen the inside but I would assume that since it was EFI it would be baffled at least to some extent.

Any chance you have the part number of the tank or the exact year and model of the van? Sounds like a really good solution!

 

[68GT500KR_Vert]

Just thought I'd throw my 2 cents in

Ron Morris makes a EFI Fuel Sender for the classic Mustangs. They actually sell a whole kit.

The site seems down right now, but I think the Fuel sender was around $80 and it has the return line built in.

www.ronmorrisperformance.com


http://www.aeromotiveinc.com/pdetail.php?prod=66
This is what I'm going with; using a new stock tank. It's the same thing they sell for $500 with the tank, just installed.

The benefit over just using bungs or a sending unit is the anti-slosh and baffle system, so you don't pump air, their is always fuel for the fump unless you run real low.

 

[67coupe351w]

The recirculation of fuel is used in some semi's to aid in raising the supply fuel temperature in cold ambients. A large deisel engine is most certianly wouldn't want to suck air.

http://www.houstonfreightliner.com/news/fabs/FAB020 - InstaHeat.pdf

You may be able to come up with a way to make it work on differential pressure rather than temperature.

Just a thought to add to the mix.

 

[Swede958]

Any chance you have the part number of the tank or the exact year and model of the van? Sounds like a really good solution!

Those are the part numbers through autozone.. I believe it was a 91 or so e-150 with a rear mounted tank. EFI of course.