E-Bodies.org Cuda Challenger Forum

Hi Everyone,

I'm trying to design a route with 1/2" fuel line on an e-body. The line needs to be made with stainless and will be made with a state of the art line bender that makes any bend perfect. I did a lot of research can't seem to find much information on the topic. These lines will run to a 800 horsepower fuel injected Hemi.  I'm looking for ideas that other have tried. Looking to do a professional job. Please post pictures or ideas or suggestions. Thanks for any help.

Ken

convertcuda@gmail.com

My best suggestion would be to call someone like Inline Tubing and order one of their 3/8" pre-bent fuel lines and using that $100 part as a template, use that hi-tech bender you mentioned to duplicate it in 1/2" SS. Then, having saved the box and noted the shipping bend, email me and we'll talk about my buying your no longer needed template. See. win-win. Good luck  :cheers:

That's actually a good idea :alan2cents:

I agree, just use the other one as a template. We ended up using braided line on this one in the stock location and that worked pretty well. What are you doing for a fuel pump and where will it be?

The template idea is good.  You can also ask them to bend you 1/2" line.  Since they have the program all ready, they might be able to do it pretty easy?   :notsure:

Following since I'm gonna do the same soon.  :popcorn:
I saved my stock 3/8 line for a template, but I got the advise to follow the right subframe connector instead of the rocker panel now, since I installed subframe connectors. But I guess I can use it for most bends.
Are you gonna run a return line also?

Thanks for the info so far guys. We are going with the tanks inc tank and I forget the company that makes the tank top deals that goes on the tank. I got those great recommendations from a guy on this site. He was right nice stuff. My plan so far I think is to make a nice appearing oval through the rear shock crossmember and bend the correct curves and go down the center of the car. I would run both lines this way, but I was concerned about heat. I think there is enough room that I could make  this look factory. 1/2 in bend look pretty aggressive going around the back end of the car like the factory did. I have been getting mixed reviews on running 3/8 and 1/2. One place says 1/2" the next says 3/8".  Engine will be carbureted and making 800 horse. Tim Bannings (FHO) is building the 572 for me.

Here's the awesome Tanks Inc.  Thinking about redesigning the fuel pump cap so it can except bigger line. The design right now is only 1/4" which I found to restrictive. What do you guys think? Would it be nice to 3/8" or 1/2" coming out right away.

Hmm, I was recommeded a 1/2 fuel line, did not know the pump only had a 1/4" connection, got the Tanks Inc tank and the GPA4 pump. I wonder if it matters...? Why run large fuel lines when there is a bottle neck in the pump?  :notsure:


Btw, are you making an access door or so in the trunk so you can get to the pump if needed? Was thinking of doing that.
Roadman and ToxicWolf did a nice one here:
https://forum.e-bodies.org/deals-coupons-vendor-specials-and-product-reviews/16/tanks-inc-fuel-tanks-for-fuel-injection-product-review/570/msg10366#msg10366

I wish I knew for sure what size to tell you would work best.  Maybe @Chryco Psycho (https://forum.e-bodies.org/mlist/chryco-psycho_4) has some thoughts? 

I would think with a good pump that the 3/8" would be enough?  :notsure:

Quote from: Convertcuda on March 14, 2017, 07:38:34 PM
This is a great discussion. I'm am making the door but it will look factory not after market. My thoughts exactly why make the input leads .25. You would think that the fuel pump would have to push harder and heat up fuel. This is why i posed this questions. Most salesmen just want you to buy but I want it to function correctly and Im willing to pay up. Any more pics up by the rear crossmember?

Please post picture of that door later, wanna se how you do it. I just might go with 3/8" since I don't have that much HP to feed. (6.1 Hemi).

I made a little door for the Cuda, I may do a better, larger one for it. I was surprised by the small outlet fittings on the pump as well but I still used large line, no problems so far. With the large lines and tight quarters it's so much easier to do the final attachment of lines to pump through the access door up top.

I mailed Tanks Inc, and they recommend 1/4" lines...

ANY of the Tube manufacture can make up that line in 1/2 then just modify the pump end.

but if they are recommending 1/4 as a supply, there theory maybe like hydraulics. smaller the more psi and stronger then a larger line.  ??

It's still about volume Dave and you can only push so much liquid through a small pipe and then there'd be the regulating to factor in, too.  :alan2cents:

i get the volume vs pressure, just don't know why they would recommend a 1/4 line thats all.

Ok how much horsepower are we talking here?

I don't think this thing even comes close to a Demon eh?

Quote from: MoparDave on March 25, 2017, 06:13:41 PM
i get the volume vs pressure, just don't know why they would recommend a 1/4 line thats all.

I agree, 1/4 seems a bit light, I think I'll go with 3/8. I got 1/2 pipes to my shower, running about 45 ft in my house, if my car would use the amount of gas that a 1/2 pipe can deliver, I could not afford to drive it anywhere  :D

I am thinking 3/8 sounds about right as well although looking at my 600HP Viper it looks like 3/8" line feeding each bank. I can't see up top if they tee into a 1/2" line or not. If I get to changing oil in it this week I'll check out the body line.

I'm am looking to make a new puck design ( the part that holds the fuel pump to the tank) and change the fittings from 1/4 to 3/8 for better flow.  I will post some pictures of the prototype when I have it done. I need it to work on a 800 horse power 572 Hemi (Tim Banning Engine from FHO) and no one makes them. Thanks for all the comments so far. Keep them coming and pictures are welcome.

Ken

Quote from: Convertcuda on March 29, 2017, 05:11:11 PM
I'm am looking to make a new puck design ( the part that holds the fuel pump to the tank) and change the fittings from 1/4 to 3/8 for better flow.  I will post some pictures of the prototype when I have it done. I need it to work on a 800 horse power 572 Hemi (Tim Banning Engine from FHO) and no one makes them. Thanks for all the comments so far. Keep them coming and pictures are welcome.

Ken

I was thinking about doing the same thing. I have a leak now ( somewhere?) so I have to drop the tank anyhow....

Quote from: Brads70 on March 29, 2017, 05:39:00 PM

Quote from: Convertcuda on March 29, 2017, 05:11:11 PM
I'm am looking to make a new puck design ( the part that holds the fuel pump to the tank) and change the fittings from 1/4 to 3/8 for better flow.  I will post some pictures of the prototype when I have it done. I need it to work on a 800 horse power 572 Hemi (Tim Banning Engine from FHO) and no one makes them. Thanks for all the comments so far. Keep them coming and pictures are welcome.

Ken

I was thinking about doing the same thing. I have a leak now ( somewhere?) so I have to drop the tank anyhow....

while your at it convert it to ORB 'O' ring fittings, I have one of the Jakefab Pucks and will be changing it from NPT to ORB, might even go to 3/8 as well, I'm only building a 600hp engine but the EFI guys have recommended 1/2" on the feed side 3/8 return

Working on the drawings right know. I thought about the o-ring idea but how do you make the fitting get to right location without under tightening and over tightening? With the pipe thread you can turn an extra round if you need it. Let me know if I'm missing something with this idea. Once I get it done will post pictures. I will making tons of extra.

Ken 715-432-5080

I took some more pictures of fuel pump mounting and the lines in case it helps someone down the road.

Early on in this thread you noted running the lines up the middle. I would be more concerned about losing a drives shaft and having it take out your lines.

I mimicked the existing line when making my return line setup.
If this car is going to be more than a strip car and get legit miles put on it. I would setup a two pump system that runs on smaller pump normally with secondary pump kicks in when needed. That limits amp draw and prevents unnecessary heating of fuel.

Here is a tip. Install electric exhaust cutouts and trigger 2nd pump with them...

Quote from: Cuda Cody on March 14, 2017, 06:00:37 PM
I wish I knew for sure what size to tell you would work best.  Maybe @Chryco Psycho (https://forum.e-bodies.org/mlist/chryco-psycho_4) has some thoughts? 

I would think with a good pump that the 3/8" would be enough?  :notsure:

From experience a 5/16" line will starve at approx 500 HP 3/8 will add approx 1/3 more volume so maybe 750 HP so at 800 Hp you want 1/2 line
Designing the fuel cap with 1/4 id is rediculous this will never work even @ 55 psi used with EFI so that has to be reworked !
I would ask Inline or fine lines to make you  a 1/2" one but shipping will be out of line as they usually bend mild steel for shipping not a good plan for stainless though so you will probably end up making your own using the factory line as a guide .
Never run the fuel line in the driveshaft tunnel  :bricks:

Quote from: Chryco Psycho on April 08, 2017, 08:06:49 AM
From experience a 5/16" line will starve at approx 500 HP 3/8 will add approx 1/3 more volume so maybe 750 HP so at 800 Hp you want 1/2 line
Designing the fuel cap with 1/4 id is rediculous this will never work even @ 55 psi used with EFI so that has to be reworked !
I would ask Inline or fine lines to make you  a 1/2" one but shipping will be out of line as they usually bend mild steel for shipping not a good plan for stainless though so you will probably end up making your own using the factory line as a guide .
Never run the fuel line in the driveshaft tunnel  :bricks:

Good info, I'll go 3/8 then, will be more than enough. Gotta look at those 1/4 connections in the pump though.

Find  a hellcat and check to see what size they use. A 3/8 line at 50psi would seem large enough compared to 3/8 at 7psi.

I'm running carbs so the fuel line has to be 1/2 for volume if I was doing fuel injection 3/8 would be perfect.

Well X HP will use X lb/hr fuel , there are no shortcuts
so 800 Hp will need X fuel no matter if it is  injected or carbed the only variable is how much more fuel you can force through  3/8"line at 55 psi vs say 12 psi using a regulator I believe 800 hp through 3/8 line would be touch & go you stand a better chance with carbs as there is extra fuel in the bowls for a few seconds anyway  :alan2cents:

Yes, I totally agree.

A little confused, your opening post says fuel injected Hemi? Definitely 1/2 inch for carbs.

Quote from: Chryco Psycho on April 08, 2017, 03:16:33 PM
Well X HP will use X lb/hr fuel , there are no shortcuts
so 800 Hp will need X fuel no matter if it is  injected or carbed the only variable is how much more fuel you can force through  3/8"line at 55 psi vs say 12 psi using a regulator I believe 800 hp through 3/8 line would be touch & go you stand a better chance with carbs as there is extra fuel in the bowls for a few seconds anyway  :alan2cents:

:iagree:

I got a headache reading this it's long.       
Fuel Line Sizing — What Size Do I Need?
by Admin on November 16, 2012 in General, Technical Articles
Lots of strange information out on the internet regarding fuel line sizing and it seems like most of the time people run way more diameter fuel line than they need. This is an interesting article that I came across that seems to be pretty relevant.
Quick reference for AN to Inch line conversion:
-6AN = 3/8″
-8AN = 1/2″
-10AN = 5/8″
-12AN = 3/4″
Fuel Line Sizing
A question that is often asked of me when dealing with high horsepower applications is: "My fuel line is nominal 3/8" id. Don't I need to increase the size of the fuel line to at least ½" id (from a #6 to a #8 or #10) to support say 600 HP"?
The answer is "NO"! A 3/8"id fuel line can easily support 600 HP given sufficient "pump head"! Given a big enough pump a 3/8" steel line could support 1000 HP.
The simple way to know is to install an electronic fuel pressure gage. If the pressure falls as the engine RPM's go up you need more pump head. More pump head can be achieved with a bigger pump, higher pump voltage and/or increasing the line size. But before you do check out the following (and remember a dirty fuel filter is often the culprit of falling fuel pressures!).
The reason most people do not understand why is because "back in the day" when carburetors ruled and everybody ran a Holly electric fuel pump running at 14 psig then into a rail mounted PRV set to 6 psig the "pump head" was insufficient to overcome the pressure drop thru the 3/8" line: particularly if the pump was at the front of the vehicle.
Let's see why today this is what I call a "wives' tale". For this example I will use gasoline. If we use alcohol we need about double the flow or with E85 we need to increase the flow numbers by around 30 % .
At WOT (Wide Open Throttle) a BSFC (Brake Specific Fuel Consumption) of ½ pound of fuel per horsepower is quite safe: resulting in A/F ratios of 11:1 or richer. Remember that maximum HP occurs at an A/F ratio of 13:1. We won't go into why one chooses such rich air fuel ratios; suffice to say that using a BSFC of .5 is generous. Since gasoline has a weight of 5.994 lbs/gallon (@ a SG of .7201 typical) then in round numbers we need 1 gallon of gasoline per 12 HP (5.994/.5). The reason I am making all these conversions for you is because typical fuel pump measurements are made in volume versus mass although mass is more accurate.
OK stay with me now as we calculate how much gasoline fuel we need to support say 1000 HP. 1000 divided by 12 = 83.3 Gallons Per Hour or 315 Liters Per Hour.
Now we are going to calculate the pressure drop thru a 3/8" steel line for a typical vehicle at a flow of 83.3 gph or 1000 HP. Most of you know that the pressure drop thru a straight pipe is less than an elbow or a 45 (same principle as your air ducting from your blower thru the piping and on into the engine). Lets assume we have about 10 feet of 3/8" fuel line. Let's double that to say 20 feet to take care of the bends in the steel pipe from the gasoline tank up to the engine fuel rail. Ingersoll-Rand publishes an engineers' handbook called "Cameron Hydraulic Data". In there they list the "Friction Of Water" thru various types of pipe. Using the pressure drop thru a new steel pipe of .364" id at 1.388 gpm (83.3 gph) we get a head loss of 35 feet per 100 feet of pipe with water as the medium. 2.31 feet of water = 1 psi therefore 35/2.31 = 15 psi per 100 feet. If I use 20 feet of steel pipe then that is 1/5 of 15 or 3 psi using water (gasoline is less viscous and flows more freely). A Fuelab Model 41401 can deliver 90 gph @ 70 psig. Can I tolerate a 3 psig drop if I need the fuel delivered at 60 psig? Yes. Will increasing the line size to ½" help? Yes the pressure drop thru a ½" line is a nominal 5 feet versus 35 feet for the 3/8" id fuel line. The ½" line will result in a ½ pound drop versus the 3 pound drop for the 3/8" line at the stated flow of 83.3 gph (enough to support 1000 HP at a BSFC of .5). The pressure drop at 1320 HP thru a 3/8" steel line might be around 5 psi.
The key to sufficient fuel supply is pumping power. As another example let's look at a flow of 1 gallon per minute at a required fuel rail pressure of 70 psig. That is enough fuel to support 720 HP. The pressure drop thru a 3/8"id line at 60 GPH is less than 1 psig! Switching to a ½" id line would result in a pressure of about 1/10 of the 3/8" line. However, given sufficient pumping power, a one (1) pound drop versus a tenth (1/10) pound drop is insignificant. At 500 HP the pressure drop is even less.
VISCOSITY SG plays no role in friction loss. The key factors are viscosity and surface tension of the liquid being pumped. Gasoline has lower viscosity and much lower surface tension than water, which is why it flows more easily thru a pipe. Consider that most greases have a lower SG than water but much higher viscosity. Which do you think flows more easily thru a pipe? SG becomes a factor if there is vertical lift of the liquid involved or very long pipe runs (which represent a large physical mass of liquid.) SG simply determines the weight of the liquid per unit volume and it boils down to more weight requires more power (HP) to move it. Friction loss is the mechanical resistance exercised by the pipe wall on the liquid. Low surface tension and/or low viscosity liquids overcome that resistance more easily. Here is a little experiment you can try. Water has relatively high surface tension. Alcohol greatly reduces that tension. Place a small drop of water on a counter top. (The counter top is analogous to the pipe wall) The water lies on the counter as a small bubble. Don't touch the water but let a very small drop of alcohol drip into the water. Watch the water immediately spread out on the counter top. The alcohol broke down the surface tension and the water molecules were free to move. If you put a drop of gasoline or alcohol (low surface tension liquids) on the counter top you see they immediately spread out. BTW, this is an area of misunderstanding with people.
Sourced from http://www.blowerworks.biz/docs/fuel-delivery-basics/fuel-line-sizing/