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Doing Fuel return line anyone done this?

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Old 02-02-2009, 12:45 AM
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Diego
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Doing Fuel return line anyone done this?

Like it says, I plan to do a return fuel system but can't seem to find anyone that done it before. I can build my own from scratch, just i do not know how to get it back into the tank. Should it be fed on the pump side? or other side? Post whatever you have on your mind. Would like to get as much info as i can.
Just keep comments like: why? stock feeds enough.. or w.e. Im mostly doing it for a aesthetics and plan to run e85 so need to upgrade a few things anyways.

Thanks
-Diego
Old 02-02-2009, 12:52 AM
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You need to return the fuel from the FPR to the pump side venturi..or you will get no fuel transfer from the passenger side tank........


I did a post on Sticks 20B thread on this with pictures I think.......

Easiest way is to use the stock fuel line as a return...and just hook up the lines in the pump canister differently.

What are you doing for a fuel pump??
Old 02-02-2009, 01:10 AM
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Diego
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Will look for that man. Thanks
I plan to upgrade the tank pump to a walbro 255 and try that out. If i need more force ill do an inline bosch 044. Also gonna add a SX FPR then a gauge to inside car.

Hopefully this setup will yield around the 400hp capacity with ease.
Old 02-02-2009, 07:41 PM
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lot of work for a proper return system----let us know how it turns out!
OD
Old 02-02-2009, 08:13 PM
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I agree with using the stock line for the return. You should change the rails if you really want to do it right. What size feed line are you planning on running?
Old 02-03-2009, 05:07 AM
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i've recently done exactly what you are doing..but on an RX-7. i went to summit and picked up a 25ft roll of 3/8" aluminum fuel line:



i ran a new feed line from the tank to the firewall and used the curren feed as my return. the fuel line bends like butter and is very tolerable to work with.

Old 02-03-2009, 09:40 AM
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Good photo.
Old 02-03-2009, 10:17 AM
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Originally Posted by mazdaverx7
i've recently done exactly what you are doing..but on an RX-7. i went to summit and picked up a 25ft roll of 3/8" aluminum fuel line:



i ran a new feed line from the tank to the firewall and used the curren feed as my return. the fuel line bends like butter and is very tolerable to work with.
If he is going to run E85, that may be a problem with aluminum fuel line.
Old 02-03-2009, 10:34 AM
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isnt aluminum line prone to vibration damage issues?
OD
Old 02-03-2009, 12:38 PM
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Yeah e85 would eat the line overtime, also pressure reasons. Idk how much pressure that particular line can handle but thats something i have to look at too.
Thanks for the photos though
Old 02-03-2009, 09:22 PM
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Diego,

If you want sketch up the setup you plan on putting together and shoot it over to me. I might be able to help point you in the right direction with specifics. Do you plan on using the existing module, modified for return system use and replace the pump?


As far as E85 goes...
Keep in mind that there are a ton things to consider if you are going to run E85.
- Electrical corrosion - ethanol is a much more conductive fluid than regular gasoline, electric current can migrate through the fluid between terminals (not good). Make sure the Walbro pump you plan to use is E85 compatible, as pump manufacturers make specific design changes to pump for E85 use to prevent current migration. There are also specific design changes to electrical connectors inside the tank for the same reason.
- O-ring swell - O-rings will swell at a much larger rate in ethanol fuels, this is more from a module standpoint, than a pump but something to look out for. Orings will swell to the point where they swell out of their pocket. Then you'll have no pressure.
- Regulator - make sure the regulator you use is rated for E85. Some platings used on regulators will not make it in E85.

These are just a few examples. This is just in the fuel tank, injectors, fuel rail, etc... are another story.

As I typed this I'm not sure if an E85 conversion is really worth your while. If you do go ahead with it I wish you luck but there is quite a bit involved.
Old 02-04-2009, 10:32 AM
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Yep---then start talking about the injectors!!
Water separation filters etc. This will be an adventure dude!!
OD,
Old 02-04-2009, 02:05 PM
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Diego
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Really? Do you guys think all that is really so important??? I mean iv seen alot of rx7s just swapping minor parts and running e85 with out problems. So im not seeing why i would have to go and do water filters and other things. lol
But will see what happens.
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