G3 Hemi fuel lines - size question

[70chall440]

So what are you guys running for your G3 Hemi fuel lines, meaning what size? I am debating on whether to use 1/2" or 3/8". Normally I would just default to the larger size and be done with it but 1/2" steel fuel is a little more difficult to find over 3/8" which is pretty plentiful. I am sure I can get it but I'd like to have options.

I want to use mild steel line, not SS or any form of braided for the long runs. I will use nylon braided for the soft lines (to the tank, to the regulator and to the fuel rails). I will be using AN fittings throughout.

I looked it up and it seems that 5.7 and maybe 6.4 use 3/8" line whereas the Hellcat uses 1/2". I see that there are adapter to go from soft line to the fuel rails so I think I am good there.

Let me know what you are running, perhaps even more importantly any issues you had or things to avoid.

Thanks in advance

 

[INTMD8]

How much power do you intend to make? 3/8 is fine unless you need to support well north of 1000hp

 

[70chall440]

How much power do you intend to make? 3/8 is fine unless you need to support well north of 1000hp

I intend to make around 450 NA. I suppose there is a possibility that I could apply a power adder at some point but doubtful.

 

[5.7 hemi]

Unless you want volume in gas inside the feed line, 1/2” would be just a waste of money.

 

[INTMD8]

I intend to make around 450 NA. I suppose there is a possibility that I could apply a power adder at some point but doubtful.

3/8 will be good. I'm at almost 600 to the wheels with a gen2 na. -6 feed (3/8) and fuel pressure is rock solid to redline.

(And I've used -6 on much higher hp forced induction cars though I'm sure many would not approve of that idea)

 

[70chall440]

Thanks, I appreciate the information and I am going with 3/8" as it makes life a lot easier.

 

[5.7 hemi]

Use it on the return also.

 

[Sixpactogo]

My 6.1 has about 450 hp. I have a 3/8" feed with 1/4" return that works fine. The car gets 20+ mpg so I never thought of questioning whether I have enough volume. Probably 5/16" would supply my needs. My 78 440 truck has 5/16" line and provides 11 mpg without starving so I can't imagine you would need anything larger than 3/8" under 600 hp.

 

[70chall440]

I will be running a return line from the regulator back to the tank (as per the Mopar crate engine instructions).

I am going to run 3/8" feed and 5/16" return.

 

[5.7 hemi]

That’ll work.

 

[What’s up dock]

Agreed, 3/8ths is fine. The first time I did it, I used a pre-bent 3/8ths line, cut the ends off, and used the brake/fuel line flaring kit to flare it to fuel injection style crimp. This way I could use the normal fuel injection fittings, for the short AN lines, to and from the filter/regulator. They also make short stub pieces for the GM style regulator/filter, push lock on one end, and male AN on the other. I can pics if that helps.

 

[70chall440]

Agreed, 3/8ths is fine. The first time I did it, I used a pre-bent 3/8ths line, cut the ends off, and used the brake/fuel line flaring kit to flare it to fuel injection style crimp. This way I could use the normal fuel injection fittings, for the short AN lines, to and from the filter/regulator. They also make short stub pieces for the GM style regulator/filter, push lock on one end, and male AN on the other. I can pics if that helps.

Thanks, please send me the pics, I am interested in seeing them

 

[What’s up dock]

I’ll take some in the morning. This is the style I’m referring to. I shouldn’t have called them push lock, but rather fuel injection quick connect.
https://www.jegs.com/webapp/wcs/sto...n+3/8&storeId=10001&catalogId=10002&langId=-1

 

[What’s up dock]

They also make 90 degree versions of some of those, which is handy.

 

[70chall440]

Appreciate it, I was looking at some of those last night.

 

[moparguy99]

Have you decided on a fuel pump yet?
working on a similar build and I am trying to figure out a setup that isnt too loud.

 

[furious70]

I've always been told and have built mine with same size return. At idle almost all the fuel is making the round trip. No need to create pressure on the return side which could potentially cause high psi at idle relative to under load.

 

[INTMD8]

I've always been told and have built mine with same size return. At idle almost all the fuel is making the round trip. No need to create pressure on the return side which could potentially cause high psi at idle relative to under load.

That would be possible theoretically but you would need a -lot- of pump.

I had a stock 5/16 feed and used a 1/4 return on a car with a 255lph pump and could still turn the regulator down to zero psi.

 

[70chall440]

Have you decided on a fuel pump yet?
working on a similar build and I am trying to figure out a setup that isnt too loud.

I will be using a Fitech 90 gph pump that will be in the tank.