AC Owners Club Forum
AC Owners Club Forum => Mk IV, Superblower, CRS and other Continuation Cars Forum => Topic started by: AK1131 on April 22, 2012, 00:11:26
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I am in the process on installing fuel injection. My buddy leading the project in concerned the existing copper fuel line may not be large enought to deliver the proper volume for the fuel injection system. A 45PSI electric pump is being installed at the tank. Please advise. [?]
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The fuel line for the 302 EFI and carb is the same I believe
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.... the line on my 88 EFI is 1/4 ID ... what concerns me is the use of copper which doesn't normally hold up well to vibration.
Ron
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It is not copper, but has a coating that looks like copper. Line is legal and will flowvsuffient fuel. mKIV can you assist here...wasn't line steel ot something coated with a copper looking coatin?
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JBo is correct, it is a steel line with a copper typr anti-corrosion coating. Very common in the UK
Up pretty early for a retired person, aren't we?
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We are going to run braided line on the supply side and use the existing copper coated return line. By the way, when I was removing the supply line at the tank. It looked fine until I moved the line. At that moment it started to leak.
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... good to know .. in 28 years in the Pipefitting Industry that would be a first ... great idea I must say ... only seen copper coated stainless once before. Now I know I can use SWADGELOCK fittings and SS braided hose ... excellent.
Thanks JB and MKIV.
Ron
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If You want to keep the original Material stay with the copper coated lines. if You have the rectangular channel beside one main frame tube and need to keep the emission lines as well maybe You dont have the room inside the channel for 2 braided hoses plus the emission lines.
I normally use plastic covered aluminum tube 10mm OD and close to 8mm ID from the tank to the engine bay or firewall position, this is enough for any fuel injection. From these tubes up to the carb or EFI unit I use the dash -6 braided hose.
You can buy these fuel line tubes at any race shop in Europe, they are connected to any -6 AN fitting by cutter type rings and a tube to AN adapter.
With these aluminum tubing You shouldbe able to run a new, durable and easy to install delivery and return line in a limited package inside the steel channel or beside the frame
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Dear Westcott,
where/how did you route the aluminum tubing?
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AK1131
I'll e mail to you a couple of pics that show the routing of mine following an upgrade of the fuel pump, filter and lines.
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Please send photos
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Can the steel fuel supply line be removed from the box channel without damage? I would like to replace it with a larger fuel line. The FI manufacturer recommends a supply line larger that the existing 1/4"
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You have to remove the silicon sealer completely on both sides of the box section. Then you must work in steps straightenIng the line at front and pull it to the rear of the car again and again until the complete length is pulled out of the channel.
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AK 11311
Photos should have come through on 22nd, April . Am away photographing at World Superbikes at the moment but will resend as soon as I return on Sunday night.
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Westcott, Thank you for the information. I am still at odds with my buddy regarding the adaquacy of the existion fuel line. Everyone on this forum tells me it is large enough but the FI manufacturer suggest 3/8's to 1/2 OD. Here is my question, With a 45 PSI fuel pump at the tank, what is the amount of fuel at the intake using the existing 1/4" OD fuel line (GPH)?
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AK1131 .. just to aid you in your project the existing fuel line is 1/4 id / 3/8 od and you looking to upgrade to 1/2 od ? This shouldnt be too hard especially if you continue using copper tube. 1/2 od is refrigeration tubing and soft enough to pull thru the path you require.
Ron
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Where to start? On our race Cobra producing 500 bhp we would return 6 mpg at full racing speeds where the throttle was fully open for the majority of the time. Average speed for a lap was about 80 mph, depending on the circuit. At 80 mph and 5 mpg we would burn 16 gallons per hour. In old units that is about 128 pints (64 quarts) per hour, or about 2 pints (1 quart) per minute. Even for 5/16" fuel line that is not a lot. We used 3/8" to be on the safe side, but also ran large bore fuel pressure regulators and fuel filter bodies. I am sure the Drag Racers can burn fuel much quicker than that, but they would be producing 800+ bhp. Answering your question, the 45 psi is not the flow rate, only the pressure pushing the fuel down the line. A Holley carb only wants to see about 5 psi, so 45 is major overkill. The pump requirement is 2 pints per minute or just over 1 litre per minute. A Holley red top fuel pump delivers 97 galls per hour at 7 psi or 12 pints per minute which is more than enough! They also have 3/8 NPT inlet and outlet connections so I would suggest going for 3/8 Aeroquip hose and fittings. Sorry for all the numbers and conversions, but that is how we worked it out for ourselves. Good luck, Andy.
PS I am watching a CCTV monitor of one of our mares who is about to foal, so I doubt I'll get much sleep tonight! See even racers have a life outside of cars!
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Damn, I just looked back at the start of your thread, and you are running EFI. From my pumping knowledge at work, as the pressure increases, the pipe diameter can decrease. If we agree on the flow required by the engine at a max of 2 pints per minute, then the 5/8" hose will be plenty big enough for low pressure pumps and even more comfortable at 45 psi. Sorry, I am so used to carbs I didn't spot the EFI bit, Andy.
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If the existing line can be removed from the box channel then I think we are going to replace it with high quality copper of a larger diameter. This will permit us to have a fare & fitting to connect to the braided fuel line. Any comments or suggestion on a use of a copper fuel line?