I am in the process of converting back to a stock tank set-up. I have everything I need except a 1/2" stock-style fuel pick-up. I have a new 3/8" unit, but since the entire line is a 1/2", I'd like to have a 1/2" pick-up. Is there anyone that can convert my new, never used 3/8" pick-up over to 1/2"

Thanks,
Cincylance
(Moparts member since 1998)

Not real sure I just jumped on Mancini's site to check and I saw those ones. It may be worth a call. I had a Friend that made his own years ago am he said it wasn't a real hard job.

I have added another pick up besides the stock one(with a sock ) and then fed both into a Y fitting to the 1/2 inch line I have also had a 1/2 inch return lined installed and welded into a stock pick up and then fed the pump from the bottom in a custom made sump

http://www.vansauto.com/sending2.html

Bottom of the page.

I just ordered some A body stuff, it was here in 2 days.

The neat thing about fluids is that they can speed up to go through a smaller area. The less than one foot of 3/8 will cause much less than 1/10psi increased pressure drop in the system.

Quick calculation, some numbers are guesses so don't shoot me:
800 hp engine running at 0.50 BSFC means it will burn 400 lb of fuel in an hour. Assume 7 lb/gallon fuel you get 400 / 7 = 57.2 gallons per hour or 1 gpm. Assume tubing has 1/16 wall, so the 1/2" tubing is 3/8"ID and the 3/8" tubing is 1/4" ID.

Calculating areas the 1/2" line is 0.1104 square inches and the 3/8" line is 0.0491 square inches.

A gallon is 231 cubic inches so to calculate velocity we divide flow by area: 231 / 0.1104 = 2092.4 inches per minute.
231 / .0491 = 4704.7 inches per minute.

Sounds bad, doesn't it? But we have to change it into something more standard like feet per second, so:
2092.4 /60 = 34.87 inches per second
4704.7 / 60 = 78.41 inches per second
Convert both to feet per second:
34.87 / 12 = 2.91 ft/sec
78.41 / 12 = 6.53 ft/sec.

My rule of thumb for a properly designed piping system is 7 ft/sec.

So let's assume 21 feet of 1/2" tubing and another system with 20 feet of 1/2" tubing and 1 foot of 3/8" tubing.

At this point I jump the tracks because I don't want to have to calculate friction factor and viscosity effects of gasoline, so I am switching to the published data for water in Type K copper tubing.
We previously figured out 1 GPM is close.
For 21 feet of 1/2" tubing pressure loss is 2.87 x 21 / 231 = 0.26psi pressure loss from end to end at the 1GPM flow rate.
For 20 + 1 it is [(2.87 x 20) + (1 x 10.32)] / 231 = 0.29 psi loss from end to end.

So you are going to all that bother for 0.03psi difference? I hope it's worth it to you, because from a practical standpoint it makes no difference whatsoever.

R.

Note to "those who were paying attention"
The 231 cubic inch per gallon is correct, but not related to the 231 I used in the last two calculations. In those calculations I used head loss for 100 feet of tubing, so had to divide by 100 to get head loss per foot. Then having to change from units of feet of head to psi, 2.31 feet of head equals 1 psi. So because I was dividing by both the 100 and the 2.31, I multiplied them first to avoid an even messier-looking equation.

You have to remember 1 thing here... this is on the
suction side so in reality atmospheric pressure is
pushing the fuel to the pump... you always want bigger
on the inlet side.... you guys do the same thing for
the oil pick up in the oil pan but most dont think
of this in the same way.... it IS the same

HA! I know it's on the suction side of the pump but it STILL doesn't make any difference. I have been designing pumping systems for 20+ years but no, I don't know anything!

Do what you want if it makes you feel better. No problem for me. Facts are facts, though, and the fact is that it'll take about 0.03psi extra to push that amount of fuel through one foot of 3/8" tubing. Even at 10,000 feet elevation you're still okay.

R.

Theory is one thing, engineers are another thing and reality is what it is Test,test, and then test some more to back up theory, if testing doesn't back up the theory change it(the theory)

I made my own fuel pickup from 5/16" to 3/8" on my '64 Polara. It would be just as easy to do it in 1/2" line, of course the sock at the end would have to be made too, but that is easy enough or do without. I just took the original piece out and formed a line to match the curve in the larger tubing, swedged it to fit and silver-soldered it in place. The heating ruined the level sending unit, but I discovered that one for a '67 Mustang fit the same, was accurate and they are cheap ($15.00 @ Bel-Kirk Mustang). I had to make a ground strap to bridge the rubber connecter of wire. Probably $30.00 in materials and some time. Easy to do

So maybe 3/8 is fine now, but that wont leave him much room to grow.

Why would you want to speed up the fuel????
To cause cavitation?

What oil pan are you using? Race or street engine?

Nice Fury!
I made a 1/2" pick-up for my Savoy a few years ago. Used 1/2" thin wall stainless steel(EBAY) and bent a curve with a handheld bender with fine ss mesh for the sock.

Ebay has 3/8 and 1/2" fuel pickups.