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Gen III Fuel supply ?

Started by anlauto, December 29, 2020, 05:18:23 PM

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anlauto

@GoodysGotaCuda or @303 Mopar or Anybody running a new Hemi......

What size fuel lines are you guys using ? 5/16" or 3/8" ? Are the main feed and return the same size ?
I've taught you everything you know....but I haven't taught you everything I know....
Check out my web site ....  Alan Gallant Automotive Restoration

GoodysGotaCuda

Quote from: anlauto on December 29, 2020, 05:18:23 PM
@GoodysGotaCuda or @303 Mopar or Anybody running a new Hemi......

What size fuel lines are you guys using ? 5/16" or 3/8" ? Are the main feed and return the same size ?

6AN tank to to corvette filter/regulator.
6AN return
6AN [deadhead] from the regulator to the rail.
1972 Barracuda - 5.7L Hemi/T56 Magnum
2020 RAM 1500 - 5.7L

My Wheel and Tire Specs

anlauto

What size fuel line steel tube from the front to back of the car ?

You can get both 6AN to 3/8" tube or 6AN to 5/16" tube.....

You're not running hoses all the way ...are you ?
I've taught you everything you know....but I haven't taught you everything I know....
Check out my web site ....  Alan Gallant Automotive Restoration


BFM_Cuda

Quote from: GoodysGotaCuda on December 29, 2020, 05:41:54 PM
6AN [deadhead] from the regulator to the rail.

I believe the smaller hemi's (345, 392) have a 3/8" (AN6) fuel rail fitting on the engine. 


edit: oops should have read your entire question first..... I would use 3/8" line from tank to engine. (standard AN6 size)

anlauto

I'm wanting to order the "pre-bent" main fuel line and return line for the car and I'm wondering if I should get 5/16" or 3/8" ?

Then I intend on chopping off both ends and add 6AN fittings and the hoses to the fuel pump at the back  and  the regulator/fuel rail up front....
I've taught you everything you know....but I haven't taught you everything I know....
Check out my web site ....  Alan Gallant Automotive Restoration

BFM_Cuda

Quote from: anlauto on December 29, 2020, 07:03:07 PM
I'm wanting to order the "pre-bent" main fuel line and return line for the car and I'm wondering if I should get 5/16" or 3/8" ?

Then I intend on chopping off both ends and add 6AN fittings and the hoses to the fuel pump at the back  and  the regulator/fuel rail up front....

I plan to do the exact same thing. Single reproduction 3/8" line front to back in stock location, adding fittings to each end.
No return line from the engine, as I plan to mount the regulator/filter on the shock crossmember in front of the tank (copying 303mopar's thread).

GoodysGotaCuda

Quote from: anlauto on December 29, 2020, 06:54:49 PM
What size fuel line steel tube from the front to back of the car ?

You can get both 6AN to 3/8" tube or 6AN to 5/16" tube.....

You're not running hoses all the way ...are you ?


I run nylon braided hose front to back on the Cuda and EFI on the Warlock as well. I'll also mention the corvette filter/regulator is near the tank, so my return line is only about 2ft.

We use the same type of nylon braided hose on 1,000,000 mile Peterbilts that leave our factory every day. It should work just fine for my fun car!

I used to get worked up over feeling like tubing was "the right way" to do it, however, I am more than happy to use hose. It's flexible, I put it where I want it and with minimal fuss.


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1972 Barracuda - 5.7L Hemi/T56 Magnum
2020 RAM 1500 - 5.7L

My Wheel and Tire Specs


anlauto

Well that's food for thought, thank you  :thinking:
I've taught you everything you know....but I haven't taught you everything I know....
Check out my web site ....  Alan Gallant Automotive Restoration

303 Mopar

I run FI hose like Goody's front to back with a return right at the filter/regulator. We are running 3/8 hard line on a '73 Cuda with a 6.1 now and it is more of a pain to install than the hose.

anlauto

Thank you for chiming in  :drinkingbud:  I have more to think about now... :thinking:
I've taught you everything you know....but I haven't taught you everything I know....
Check out my web site ....  Alan Gallant Automotive Restoration

anlauto

Okay...I'm feeling dumb here, so please educate me on this Gen III hemi stuff :crazytalk:

I recently installed a FiTech fuel injection on a 340...it had two outlets...one was the feed line and one was a return line....made simple sense to me...you pump gas into a throttle body...and it returns the gas it doesn't use  :dunno:

The new 392 Hemi I've ordered hasn't arrived yet, so I haven't had a look at it....Are you guys saying it only has one outlet which is a feed line ?  and any type of return is done at a regulator ? What about any fuel the engine doesn't use ?   I'm very confused :looney:

@303 Mopar @GoodysGotaCuda sorry to keep bugging you guys with these tags, but I really look to you for advice  :drinkingbud:
I've taught you everything you know....but I haven't taught you everything I know....
Check out my web site ....  Alan Gallant Automotive Restoration


GoodysGotaCuda

Quote from: anlauto on December 31, 2020, 10:38:22 AM
Okay...I'm feeling dumb here, so please educate me on this Gen III hemi stuff :crazytalk:

I recently installed a FiTech fuel injection on a 340...it had two outlets...one was the feed line and one was a return line....made simple sense to me...you pump gas into a throttle body...and it returns the gas it doesn't use  :dunno:

The new 392 Hemi I've ordered hasn't arrived yet, so I haven't had a look at it....Are you guys saying it only has one outlet which is a feed line ?  and any type of return is done at a regulator ? What about any fuel the engine doesn't use ?   I'm very confused :looney:

@303 Mopar @GoodysGotaCuda sorry to keep bugging you guys with these tags, but I really look to you for advice  :drinkingbud:


  • In factory form the Hemis do not have any sort of return line. The fuel pump is pulse width modulated to hit the target rail pressure, from what I recall.
  • In aftermarket form, people more or less do the same, however they put a regulator inline between the pump and the fuel rail.
  • "Fuel the engine doesn't use" isn't really a thing. The fuel stays in the rail until it's consumed, there's not much reason to send it back to the tank.

I'll also add that my Holley Sniper is setup very similarly. My fuel pump setup is regulated at the tank itself and I have a single line going to the throttle body. The "return" port is blocked.
1972 Barracuda - 5.7L Hemi/T56 Magnum
2020 RAM 1500 - 5.7L

My Wheel and Tire Specs

GoodysGotaCuda

1972 Barracuda - 5.7L Hemi/T56 Magnum
2020 RAM 1500 - 5.7L

My Wheel and Tire Specs

Brads70

Just thought I'd add in this..... I've done 2 cars now and 3 race cars with this from Frozen boost . Much cheaper than the traditional Aeroquip  fittings etc.... they say the Teflon hose is good for FI pressures as well as carb set ups. Its been on the Challenger for 8-10 years now with no issues.... :alan2cents:

http://www.frozenboost.com/index.php?cPath=219&osCsid=6dd5cc73b412f25e6949c519f71b64d3

anlauto

Man, nothing like being schooled.....thank you....

So if I'm understanding this correctly....The pump would constantly run fuel, past the regulator to the engine....If the engine is not running, once the pressure at the fuel rail is met....the regulator would come into effect....sending the unwanted fuel back to the tank.....if you have the pedal to the metal the regulator would keep sending fuel to the engine, but if you're at a traffic light, the regulator would send any extra fuel back to the tank...

I think... :looney:

So I'm assuming you need to find out what pressure the engine requires and set the regulator at that level....Would I need an "in-line" pressure gauge as well ?
I've taught you everything you know....but I haven't taught you everything I know....
Check out my web site ....  Alan Gallant Automotive Restoration