Fuel line run question

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rod7515

rod7515

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I need to change the way my fuel line runs because of heat from my headers. I want to stay within the rules for NHRA drag racing as I hope to run my car a few times. I am working with a 66 Dart that I have added frame rail tie ins. I ran 1/2" aluminum fuel line from the rear fuel pump/tank all the way up on the inside of the frame rails but when i got to where the TTI passenger header collector ends the fuel lines are about 3" above the headers and the heat transfer when i sit has caused issues in restarting. I am also wondering about how your fuel line comes into the engine compartment as I know it is not allowed on the firewall and when mine runs up the right inner fender it again gets lots of heat from the headers.
I was wondering what others have done when running your fuel line so I am legal but it will get me away from the header heat.
Thanks Rod
 
I've used heat sleeve from DEI to keep steel fuel lines cool. It works great and may be worth looking into. They make a bunch of great products that may help you. Line and Hose Heat Shield Sleeve | Design Engineering

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mopowers, thanks. I should have mentioned Ive already wrapped the entire fuel lines both supply and return with the DEI wrap. To be honest I didnt notice any change once i installed it. Once I drive my Dart for 20 minutes then shut it off and it sits about 10 minutes its almost impossible to restart. I must shut off my fuel pump and then if it starts most times when i turn the pump back on it will shut off. It may take me 2 or 3 attempts before it will keep running. My fuel pressure normally runs between 6-7 psi and even during these attempts it doesnt change. When it does restart i need to keep it throttled up above 1500 RPMs before it will setttle down and idle. This may take 15- 20 seconds.
Dana67Dart, that is something I have not tried yet. I have only ran the **** they call high text 93 octane in a normal fuel supply store. There is a place about 15 miles from here that sells the ethanol free fuel. Ill have to give that a try.
Someone said I should try running the line inside the frame rail but Im not sure thats possible and even if it would be it will add extra bends which will create fuel pressure drop? And what kind of structural problems would that create by drilling holes in the frame rail to run the line thru?
Thanks Rod
 
Many auto manufacturers make heat sheilds to place between items that cant take the heat.

Radiant heat is the enemy
 
Another line of thought, don't have it dead head...make a return line. There are other solutions, but this one should work.
 
Also to note: Gasoline is more volatile than ethanol (i.e. has a lower heat of vaporization value compared to ethanol), so running gas with less ethanol really doesn't sound like the move here. I have heard this for many years, but looking at the delta H values, it just doesn't make sense to me (maybe I'm missing something). Finding a better route for the fuel lines, or better protection from heat soak and radiant heat is what you need.

On my Barracuda I have the fuel line (1/2 aluminum hard line) from fuel cell to the passenger side shock tower with heat shielding (similar to the aluminized shielding above), then a single 1/2 Push-Loc line (NHRA rated) to the carb....its not the prettiest setup, but it works well.

Edit: Just re-read the original post....I would do whatever you can to NOT have the fuel line above the collector, that is going to cause you all kinds of problems with both heat soak and radiant heat. I would (at the very least) move it off to the side to get less heat soak.
 
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flyfish said:
Also to note: Gasoline is more volatile than ethanol (i.e. has a lower heat of vaporization value compared to ethanol), so running gas with less ethanol really doesn't sound like the move here. I have heard this for many years, but looking at the delta H values, it just doesn't make sense to me (maybe I'm missing something). Finding a better route for the fuel lines, or better protection from heat soak and radiant heat is what you need.
Click to expand...
All I can tell you is with typical 89 octain pump gas with ethanol my stock 273 dart would almost die after 50 yards of normal acceleration when the engine was hot on a hot day and you could watch the clear fuel filter fill with vapor ( kept pressure)

Then I switched to 89 octane alcohol free and have not had the problem happen again. And I have tried to make it happen. 98 degree day sitting in a fast food line in gear for 5 to 10 minutes is all it would take in the past. Now ideling in gear for 15 minutes 98 deg day. Then start driving and no issues under acceleration, even heavy acceleration.

Science is not always right in the real world. Way more variables there.
 
Yeah, it's weird that ethanol-laced fuel tends to have more vapor lock-related issues than straight gasoline, even though gasoline is technically more volatile than ethanol. Does anyone know why that is?
 
Dana67Dart said:
All I can tell you is with typical 89 octain pump gas with ethanol my stock 273 dart would almost die after 50 yards of normal acceleration when the engine was hot on a hot day and you could watch the clear fuel filter fill with vapor ( kept pressure)

Then I switched to 89 octane alcohol free and have not had the problem happen again. And I have tried to make it happen. 98 degree day sitting in a fast food line in gear for 5 to 10 minutes is all it would take in the past. Now ideling in gear for 15 minutes 98 deg day. Then start driving and no issues under acceleration, even heavy acceleration.

Science is not always right in the real world. Way more variables there.
Click to expand...
Weird...like I said, I might be missing something, it just doesn't make sense to me. For example, I run e85 (about 85% ethanol and 15% gasoline) and I have never had such an issue. I drive the car a lot on the street and the track, no problems.

Dana67Dart said:
Science is not always right in the real world. Way more variables there.
Click to expand...
Funny! The second part of that statement (way more variables there) is exactly why predictions using science go sideways sometimes. You need all (or most) of the variables or you will end up in left field somewhere.

I'm sure I'm probably missing something, would love to know if anyone has any insight.
 
I ran 1/2 aluminum line, outside the frame rail and subframe connectors, (like nhra likes it) continued up into engine compartment outside the frame and away from the headers, short piece of braided line to the regulator mounted on the passenger inner fender, then two braided line straight to the bowls.
 
Run a bypass regulator with return line, install thick heat insulator carb gasket, make a heat shield for front bowl; the radiator hose cooks the front bowl. I'm in Florida heat and this setup works on my street strip car driven 50 miles to the track.

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mderoy340, your lines look so similar to my lines. I am attaching some pics of mine and I cant find any right at the headers but mine are pretty much the same as yours. I have insulated them with the heat wrap and also built a 1/8" shield between them and the header collector. Also where my fuel lines go up into the engine compartment they catch more heat from the side of the headers. As you can see I also have a 1/2" return line as well. I would like to see where your lines come up and into the engine compartment and i see your line stays inside the alternator like the factory run where mine comes over the alternator.
sr4440, my regulator is on the inner fender but I am going to move it to the side of the intake and use it as my fuel block as well.
My plans when adding this new intake and carbs will be to route my fuel lines differently. Here is what I found in the 2021 NHRA rule book on fuel lines:
1:5 FUEL SYSTEMS Location: All fuel tanks, lines, pumps, valves, etc. must be outside of the driver’s compartment and within the confines of the frame and/or steel body. Cool cans, fuel-distribution blocks, etc. must be located at least 6 inches forward of the flywheel/ bellhousing area on rear-wheel-drive (RWD) vehicles, and on opposite side of flywheel/housing area on front-wheel-drive (FWD) vehicles. Fuel pressure gauge isolators, with steel braided line, may be mounted on firewall.

I was always under the impression that fuel lines needed to stay inside the frame rail but reading this makes me believe that as long as they stay inside the body I could move them to the outside of the frame rails. What are your thoughts when reading this?
Appreciate everyones input with this. Thanks for your thoughts.
Rod
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Some folks cross thru the frame rail and run lines inside the passenger wheel well. I chose not to go that route on a street driven car. I'm not an NHRA tech expert, best to talk with the folks at the track you plan to run.

Section 1.5 also states:
Fuel lines (except steel braided lines) in flywheel/bellhousing area must be enclosed in a 16-inch (40.6 cm) length of steel tubing, 1/8-inch (3.2 mm) minimum wall thickness, securely mounted as a protection against fuel line rupture.

Looking at your hard lines running up the firewall they should be flex or shielded by the rules.
I used my floor jack handle to run my hard lines thru going forward in the bell housing area and used the stock fuel line route. At the stock mechanical pump location the lines transition to shielded flex. Heat rises so I figured if I'm near the header I want to be below the heat source. I'll have to take a picture of this later today and post it.

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My car too has a 1/2" aluminum line ran along the inside of the frame tie, 2X2 square tube. At the front, right behind the trans cross member it crosses over and runs along the top of the of the apron above the front suspension. I used a bulkhead fitting to come through to the engine compartment, the regulator is mounted in a similar location to the OP's.

I drive on the street quiet a bit and have never had a issue with anything hitting the line, yet anyway.
 
The aluminised fibreglass cloth shown in post #2 is what I use to insulate the fuel line.
I use the same product to cover my A/C cleaner housing, which gets cold air induction; it helps keep the incoming air cool.

I would NOT use this stuff on high tension leads as it can bleed off spark energy.
 
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