I am going to need to upgrade my fuel system with this rebuild so i have been thinking about some things. My wallet is pretty tapped right now from all the parts bought, so i am wanting to do the fuel system upgrade as cheaply as possible, as i hate to say. Right now i have a 255 lph walbro intank, stock lines, rails, and an aftermarket replcement AFPR. here was my idea:
keep the stock lines intact, everything will be the same, but the changes will be made on the fuel rail. TAke out the reurn line out of the rail and weld a -8AN fitting in its place like most of you do when you upgrade. instead of tossing that return line compression fitting away, drill a hole in the pipe that goes between the 2 rails toward the front of the rail and weld the old return line compression fitting there. This way you can still use the stock return line and whatever AFPR you use to return the fuel up to the top of the fuel tank. THen, weld a -10AN fitting to the bottom of the gas tank for a sump, take that to an outside aftermarket fuel pump, like aeromotive, or whatever. From the output of the pump go -8AN to a filter, and out of the filter to the fuel rail fitting you welding in the original return line spot. so on one rail you will have the stock lines with the intank pump, and on the other side you'll have the output of the aftermarket in line pump from a sump fitting on the tank.

This way, you would only have to buy 15-20 ft of fuel line( havent measured) a lot less fittings, and proably a lot less hassel and money. I know this isnt as good as a full out upgrade, but it would be a lot cheaper and will utilize a lot of the stock parts.

A few things i was wondering though. I would most likely just run the inline pump only when im racing amd spraying the juice. During this time when both pumps are running, will the AFPR be able to bypass this much fuel while still being able to maintain the proper pressure? Would the stock return line allow enough flow for both of the pumps to return to the tank without building up back pressure to the injectors? I know that an aeromotive pressure regulator isnt that much, but this is just in theory of keeping as much stock things in tact. thoughts? questions? comments? suggestions to make this idea better?

Thanks

Chad

 

Did I not explain my idea well or is it just out of the question/stupid? Well does anyone know approximately how much fuel a 3/8" line will flow under 45 psi? I guess that would be my main concern, if the factory-sized fuel return line can handle both pumps by passing ot the tank at an idle.

Chad

 

I always thought that you wanted a return line just as large as your supply line.

 

i thought i have read on some people cars they use 8AN for the feed, and 6AN for the return. butim not sure. anybody know the difference in size between an 8AN line and 3/8"?

 

The "number" in the AN size is the number of "16ths" in the inside diameter. -6AN = 6/16 = 3/8". -8AN = 8/16 = 1/2". I feed both an intank 205LPH pump and an external/sumped 205LPH pump through a -6AN line. The line ony splits about 8" from the back of the rails. I run a single -6AN return line off the cross-over pipe (see pic in the other fuel line thread). The entire system is rated at 1,000HP. I have only run 800HP on it, and the fuel pressure is extremely stable.

 

I have checked out your setup before i even posted this idea. I will probably go something similar to that route if this idea i have falls through. I was just trying to use some of the stock lines and fittings. So, really teh stock 3/8" return line should flow enough as a 6AN line like you have. Any ideas on if this thing will work or not?

 

i was thinking about running a walboro 255 intank and an inline electric pump say aeromotive on the same line. after the inline pump step up to 1/2 line and split to -8AN fittings on my rails.

does this sound good? how much hp would it support?

thanks,
mike