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Discussion Starter · #1 · (Edited)
Fuel Tank Sock ?

Here's a question for you FI guys and any one else that wants to make a comment. I opened up the gas tank on my GT and checked the inside, it's clean, with no rust anywhere that I could see, and I have an intact filter sock over the fuel outlet. I'll be running the stock fuel outlet line, cut to the appropriate length to a 100 psi can filter, then to a 70 psi bypass fuel pump, then to another 100 psi can filter, alongside the pump, then 1/2" line to the fuel rail on my V-6 which will bypass fuel at 50 psi. Here's the question, should I take out the sock or leave it in. Oh yeh, the pump and filters will be in close proximity to the fuel tank in the rear of the car. I'd like to have feedback before I paint the tank and put it back in the car. TIA.

Ron
 

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Fuel Flow

There is goingto be more fuel flow than standard and that 'sock' eventually blocks up with standard fuel flow. It is easy to remove right now, with the tank out and you are adequately protected with the filter system you intend using - which BTW can be replaced outside the tank if anything blocks up, because it is already accessible outside the tank. Rip it out, Ron!
 

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Discussion Starter · #3 ·
Thanks for the feed back Jim, I didn't even consider that the sock would eventually fail. So out it comes. Thanx.

Ron
 

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Discussion Starter · #4 ·
A little Magnum flashlight, a long piece of 3/16" stainless tubing, a fair amount of twisting and shaking the tank and the sock came out it 3 pieces. Of note, while I was looking at the outlet from inside the tank, it appears to be a union fitting going through the tank with a jam nut on the inside. So it may be possible to remove the fitting and put a larger sized fitting in there. I'm going to hold off on that for the time being, I've got a new steel fuel line coming from OGTS and the distance from the outlet to the filter/pump/filter will be fairly short and I don't believe there will be any fuel delivery problems in that short of a run. Time will tell. :rolleyes:

Ron
 

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Finally found the line drawing of the fuel sock and its removal. It does look like the sock is mounted on a screw-in ring that the fuel line outlet threads into. I would bet that the outer thread is probably soldered into the tank to prevent leaks. How ever an intrepid modifier could overcome that wee obsticale if the tank was out.
 

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Discussion Starter · #6 ·
It could very well be Jim, that the nut I saw on the inside of the tank was welded in. I'll take another look tomorrow. I'm going to try and take out the union fitting and see if I can open it up a tad with a drill and not sacrifice wall thickness. My welder picked up 20 feet of 1/2" and 1/4" stainless tubing today for the pump outlet and returns. With 1/2" on the pump outlet to the fuel rail and a can filter in between, I should have a real good accumulator action, especially with a 70 psi pump and 50 psi regulator at the fuel rail. The 1/4" tubing will be used for the bypass relief on both the fuel rail and the pump. Now all I've got to do is figure out where to mount the pump and filters, but that won't be too hard to do. My choices are inside by the tailights or outside close to the tank outlet. When I get that far I'll make that determination.

Ron
 

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There will be $20 of fuel in the lines alone! :eek:
 

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Discussion Starter · #8 ·
Not quite Jim, but if I used all 20 feet of the 1/2" tubing it is only 47.124 cu.in. I don't have my weights and measures handbook handy, so I don't know how close to a gallon that would be. But if it is a gallon, it would only be $2.41 to fill the line. One good thing though, if it holds that much, I'll be able to go further on down the road after a fillup than your regular GT. :D

Ron
 

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1 litre = 61 cubic inches so if not gallons in there at least close to a litre!
 

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Discussion Starter · #10 ·
Jim, I must have had a "Senior Moment" at dark thirty last night, I've known for years the magic number for converting liters to cu.in. and vice versa, was 61. That goes back to my family's boat racing days when the largest limited class engine allowed was 7 liters, that equates to 427 cu.in. Still, that much extra gas will put me a mile or two further on down the road. :cool:

Ron
 

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SOLUTION for FI fuel starvation!!!

I was just thinking about this and lo & behold, you 2 are discussing it right here!

I remember Roger Wilson telling about one of the "inventive" methods used by an old racer, Smokey Yanuck(?), to get around the rules. And it was using a "very" long fuel line.

Since I'm scared to death about cutting up my gas tank let alone removing it. I was thinking there must be another way. Well, I was just thinking I could use the long fuel line approach to get around the fuel starvation problem when the tank is less than half empty while going around a curve. And thanks for supplying the conversion factors.

At 1/2" diameter, I'd only need 20 extra inches to have an extra liter of fuel in the line for getting thru the curve, right?

surface area of 1/2" dia. circle = 3.14 sq. in.
3.14 X 20 in. = 60.28 cu. in. ( just shy of 1 litre )

Any reason why this wouldn't work? Is the stock fuel line 1/2" diameter?

Since there will still be a gap in the line, will I still feel the fuel starvation after the curve? Or will fuel fill the gap once thru the curve?

Thanks,

Manny
 

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Discussion Starter · #12 · (Edited)
Your formula for area is a little off, it's actually pi r2 = area times the length of the tube. So that would be: .25 X.25 X 3.1416 X length, so in my case it was 47.124 cu. in. for a 20 foot length of stainless tubing or about 3/4 of a liter. That old time racer was "Smokey Yunick" and he had a column in one of the car mags years ago. As far as the fuel filling the gap so to speak, the air bubble will be pumped through the pump and into the carb where it should be vented out as the gas fills the line again. The original fuel line on a GT is about 1/4" ID, so you should have twice as much fuel available as before, but that's a guess. HTH

Ron
 

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namba209 said:
Your formula for area is a little off, it's actually pi r2 = area times the length of the tube. So that would be: .25 X.25 X 3.1416 X length, so in my case it was 47.124 cu. in. for a 20 foot length of stainless tubing or about 3/4 of a liter. That old time racer was "Smokey Yunick" and he had a column in one of the car mags years ago. As far as the fuel filling the gap so to speak, the air bubble will be pumped through the pump and into the carb where it should be vented out as the gas fills the line again. The original fuel line on a GT is about 1/4" ID, so you should have twice as much fuel available as before, but that's a guess. HTH

Ron
Thanks Ron,

I used the formula for circumference instead of surface area. DOH! I thought 20 in. seemed extremely short. :)

As for the carb venting the air bubble, I have F.I. So it sounds like I'll still experience some starvation?

Thanks,

Manny
 

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F I systems HATE air in them. A lot gets purged back to the tank through the return line but a few bubbles always go through the injectors.
The 'rice boys' use a thing called a "dash pot" to suck the fuel from. This is a seperate canister that fuel is pumped into from the tank with a hi-capacity, low pressure electric pump so that it is kept full. The Hi-pressure fuel injection pump then draws from this constant supply. Stock cars usually have a surge chamber in the tank but this external pot can be used when the tank is not baffled - as in the GT. Have a look in a 'boy racer' shop.

Smokey Yunick was/is? an engine and race car builder extriordinaire. I believe that he once accused 'Junior' Johnson of cheating because "I shave as close to the rules as possible and he beat me!" I think their rivalry was basically friendly though! It is well worth getting hold of either of their books about SB Chevy engine building as they are still powerhouses of information that applies to all engines.
 

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Discussion Starter · #15 · (Edited)
You may not have a fuel starvation problem with the larger line, it depends on where the pressure regulator is on the fuel rail. Remember air can be compressed, fuel cannot for all intents and purposes. It also is important where the fuel pump is. If it's inside or close to the tank it will cavitate until it picks up fuel again then pump the fuel compressing the air, if the fuel rail regulator is high enough on the fuel rail it will dump the air into the return line and the fuel will replace it. It is also important that the fuel pump pressure exceeds the pressure regulator so you will have constant fuel flow through the pump to keep it from overheating. So all things being said, the larger line may be enough to keep you from running out of gas in turns, if not, then I would suggest a surge tank if you have an external pump, something in the area of a quart should suffice with a vent line going back to the tank to bleed off any air that may enter through the feed line and possibly have your return line from the fuel rail dump there too. Any excess fuel would be vented back to the fuel tank. through the vent line. HTH.

Ron
 

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A lot of great ideas

Once again, this community has a lot of great ideas. That surge tanks sounds like my other idea but I didn't know that I'd need another fuel pump to make it all work. Anyways, I will look into it.

Thanks for sharing.

Manny
 
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