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Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938138
10/25/15 01:22 AM
10/25/15 01:22 AM
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Ran -12 line from the cell to the Magnafuel500 pump, then -10 line to the regulator, then -8 line to the carb. Wiring to the pump is a often overlooked problem.


69 GTX 68 Road Runner
Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938200
10/25/15 09:33 AM
10/25/15 09:33 AM
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Jerry Kathe Offline
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TBoomer - Monte Smith and Mark Whitener have answered this inquiry.....go back and re-read those posts. Been there, done that.
(FWIW/IMO)

Re: Fuel Volume vs. Fuel Pressure [Re: Jerry Kathe] #1938209
10/25/15 10:06 AM
10/25/15 10:06 AM
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Originally Posted By Jerry Kathe
TBoomer - Monte Smith and Mark Whitener have answered this inquiry.....go back and re-read those posts. Been there, done that.
(FWIW/IMO)



Like:
"Bigger lines, hold more volume and the column of fuel is harder to move in a G situation, so you need more pump. Smaller lines help that...."

Just don't tell your physics teacher. laugh2


If you can't dazzle them with diamonds, don't waste your time, because nothing will
Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938223
10/25/15 10:40 AM
10/25/15 10:40 AM
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Its about volume, not pressure.

I don't invest much concern when comparing say a -10 line v/s a -8 line in column reaction to G-forces - but there is some relevance to the general concept and statement.

FWIW - in having a professional education and occupational discipline in the engineering field.....I understand hydraulic physics and dynamics, no need to consult the teacher.

Re: Fuel Volume vs. Fuel Pressure [Re: Jerry Kathe] #1938236
10/25/15 11:01 AM
10/25/15 11:01 AM
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Originally Posted By Jerry Kathe
Its about volume, not pressure.

I don't invest much concern when comparing say a -10 line v/s a -8 line in column reaction to G-forces - but there is some relevance to the general concept and statement.

FWIW - in having a professional education and occupational discipline in the engineering field.....I understand hydraulic physics and dynamics, no need to consult the teacher.

work

I have no idea what you are saying, other then your stated qualifications. To be clear, explain what "relevance to the general concept and statement" means relating to this topic. I would like to hear someone explain how tubing size diameter effects PSI, under g forces. I tried, but everybody? got lost in the weeds, to use another analogy. eyes


If you can't dazzle them with diamonds, don't waste your time, because nothing will
Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938252
10/25/15 11:28 AM
10/25/15 11:28 AM
Joined: Nov 2003
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Chandler, AZ
Duner Offline
top fuel
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I've been making 700rwhp with only a 5/16" fuel line forever.....

I don't think my fuel injectors know anthing about G-forces anyway.


(sorry, couldn't resist)

Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938269
10/25/15 11:55 AM
10/25/15 11:55 AM
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Carburetor.....
you dont want pressure because of a airiation....less is best.

You want volume, this is what maintains the same level of fuel in the bowl even considering gforce efffect.

Fixed displacement pumps will have volume and pressure as a linear effect.

If you use a pump with big gph numbers...you can reduce delivery pressure a bunch and still have adequate volume.

Do this with your small pumps....set the carb pressure at 3.5 psi and make a hit, then set it at 7.5 psi....make another hit and report back.....

Another prior comment about needle and seat size and bowl entry point is important.

Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938302
10/25/15 01:03 PM
10/25/15 01:03 PM
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Give it up Jerry...........you can't have a legitimate race car discussion with some here. Now if you want to talk about water cisterns, gravity on Saturn and golf balls, you are in the right place.

Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938310
10/25/15 01:15 PM
10/25/15 01:15 PM
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W. Kentucky
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Just to throw something else in the mix of needle/seats and bowl entrances, the regulator. When I went to the Magnafuel 275, 1/2" aluminum and 8AN lines I also went to a Holley big port regulator. Looking at the sizes of the inlets and outlets I'm not sure it was money well spent.

Discussion?

Re: Fuel Volume vs. Fuel Pressure [Re: Monte_Smith] #1938330
10/25/15 01:44 PM
10/25/15 01:44 PM
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Glendora Ca.
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As I read through all of this I am reminded of the mistakes/leasons I have learned about pump placement size/style of the pump, running voltage to the pump, tank placement and g-force. But I am just a dumb electrician, not a rocket doctor.

Some need to remember there is a big difference between a tank at the rear of the car way behind the regulator and carb and a tank ahead of the pump and the rest of the system.

The fuel aeration/pressure discussion is interesting, and I have to think about how some push vacuum referenced regulators and the effect that would have in the fuel bowl.

Thanks for a discussion that is useful



"Just a Bracket car dressed up like a streetcar"
Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938341
10/25/15 02:11 PM
10/25/15 02:11 PM
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For a vast over simplification of pressure vs volume.........lets relate it to electricity. A 20 gauge speaker wire will carry 12 volts(pressure) and so will a 00 welding cable, but only one of those will crank your car, because only one carries enough volume(amps) of electricity to operate the starter motor. I can crank the pressure(voltage) up on the small wire to 16 volts and it still won't crank the car.

So your motor requires a volume of fuel to run properly. If the pump and line can't supply that volume, no realistic amount of pressure increase is going to overcome the lack of volume.

As for the lower pressure, decreasing aeration of the fuel and the car running better...........that has been proven time and time again on the RACETRACK........NOT on a piece of paper

Last edited by Monte_Smith; 10/25/15 02:13 PM.
Re: Fuel Volume vs. Fuel Pressure [Re: Monte_Smith] #1938346
10/25/15 02:31 PM
10/25/15 02:31 PM
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jcc Offline
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Originally Posted By Monte_Smith
Give it up Jerry...........you can't have a legitimate race car discussion with some here. Now if you want to talk about water cisterns, gravity on Saturn and golf balls, you are in the right place.


When you label other peoples comments "crap", I would agree about the comment of having legit discussions here, about anything.


If you can't dazzle them with diamonds, don't waste your time, because nothing will
Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938354
10/25/15 02:54 PM
10/25/15 02:54 PM
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off the grid
340B5 Offline
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Considering the conversation has turned to aeration a couple times;

I have a deep (11") fuel cell and have never had a down tube on the return inside. I've always reasoned that the bubbles will float to the top before they get pulled into the inlets. Would it benefit me to use a downtube?

I was planning on finally putting one on this winter.


Yeah, it's got a smallblock.
Re: Fuel Volume vs. Fuel Pressure [Re: jcc] #1938365
10/25/15 03:13 PM
10/25/15 03:13 PM
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Originally Posted By jcc
Originally Posted By Monte_Smith
Give it up Jerry...........you can't have a legitimate race car discussion with some here. Now if you want to talk about water cisterns, gravity on Saturn and golf balls, you are in the right place.


When you label other peoples comments "crap", I would agree about the comment of having legit discussions here, about anything.
Here is the thing.........you don't agree with me, that's fine, because I really don't care if you do. I base my suggestions here from things I have tried and KNOW they work, not based from some formula that SHOULD work or is written in a book. So yeah, when you start talking about water cisterns on Saturn and the differences in gravity to prove your point, which is totally irrelevant to the discussion at hand, I zone out and consider that info useless. Nobody care about that stuff. They want to know what will WORK on their race car.

If you and a couple others, think you are the ONLY ones on here with an engineering background, you are sorely mistaken. And if there is one thing I have learned working with other engineers, is that because they can figure things out on paper, doesn't mean they can make anything WORK. Going through that right now, with a self proclaimed "genius" engineer we hired. Nothing he has done for us has worked. So what does that mean........it means a piece of paper is a piece of paper

Re: Fuel Volume vs. Fuel Pressure [Re: 340B5] #1938392
10/25/15 04:07 PM
10/25/15 04:07 PM
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State of confusion
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Originally Posted By 340B5
Considering the conversation has turned to aeration a couple times;

I have a deep (11") fuel cell and have never had a down tube on the return inside. I've always reasoned that the bubbles will float to the top before they get pulled into the inlets. Would it benefit me to use a downtube?

I was planning on finally putting one on this winter.


When my Magnafuel 300 pump died on me the tech at Mag said it had been cavitating and asked about the down tube which I did not use till AFTER I got the pump back. He also said running the cell low and hard braking can uncover the sump and also kill it. He also mentioned foam which I run can also crowd the outlet fittings ALSO causing a restriction. So I now run the down tube, keep the cell at least 1/2 full and will address the foam issue somehow.......


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938413
10/25/15 05:02 PM
10/25/15 05:02 PM
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MI, usa
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If pressure is being measured directly at the line between the regulator, how could there be inadequate flow to the needle and seat? If there wasn't adequate volume in that line to keep a steady state of fuel at the needle and seat wouldn't the pressure reading go down? As long as the regulator can feed the volume of fuel held in that line with the needle open the pressure will remain constant. Pascals law states; "When pressure on any portion of a confined liquid is changed, the pressure on every other part of the liquid is also changed by the same amount." The needle and seat causes the volume of liquid to no longer be confined. If the needle is open the confined area must be constantly refilled equaling the exiting volume to maintain the same pressure. Obviously flow over time and quality of pure liquid could change and maybe the instruments used to monitor it aren't quick or accurate enough to record the true story. The argument about aerated fuel and using the least pressure necessary makes sense. When we use pressure vs volume maybe it isn't that we don't have adequate flow but the "quality" of the fuel being delivered isn't 100% liquid? Or am I missing something?
Doug

Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938425
10/25/15 05:19 PM
10/25/15 05:19 PM
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Charlotte, North Carolina
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So, since I started racing, (back when electricity was first invented, I think) I used 2 Holley blue pumps with Moroso springs, 2 1/2" fuel lines, into 2 Holley regulators tee'd together and into the fuel bowls. I think the Moroso spring and shim kits set the line pressure around 28 psi, and then adjusted the regulators to 5 psi each, which would be 5.5 when both pumps were running. Would lowering the regulator pressure be beneficial as far as aeration or is this a satisfactory setup? Still unsure of a new setup for the new combo. Was thinking leaving the pumps, feed the supply lines into a Y block in front of a single four port regulator. Oh, and the lines off of the fuel cell are -10.
The biggest addition to my new combo will be adding an alternator this year.


[image][/image]
Re: Fuel Volume vs. Fuel Pressure [Re: dvw] #1938488
10/25/15 07:11 PM
10/25/15 07:11 PM
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Bend,OR USA
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My comments on fuel voulme is that many things in a fuel system can be a potential and actual flow(volume) stopper, like .090 needles and seats on a 800 HP motor with one 1050 Dominator carb. You would have reasonable fuel pressure with insuffeint fuel volume to adequately feed that motor due to the needle and seat restrictions, been there, done that realcrazy


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Fuel Volume vs. Fuel Pressure [Re: tboomer] #1938496
10/25/15 07:18 PM
10/25/15 07:18 PM
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jersey
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I'm not a smart man.
But you know who I'm going to listen to in a discussion like this?
Guys with real hands on knowledge of making a car go down a track fast.
Guys like Monte, and Thumper. Because they have tried "theories" "formulas" "calculations",
And what ever else a book says will work.
And what usually happens? They don't work. What works on paper, or even a dyno, might not happen going down the track.


526 cubes of angry wedge, pushbutton shifted, 9 passenger killer!
Re: Fuel Volume vs. Fuel Pressure [Re: Spaceman Spiff] #1938521
10/25/15 07:55 PM
10/25/15 07:55 PM
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United Socialist States of Ame...
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Originally Posted By Spaceman Spiff
I'm not a smart man.
But you know who I'm going to listen to in a discussion like this?
Guys with real hands on knowledge of making a car go down a track fast.
Guys like Monte, and Thumper. Because they have tried "theories" "formulas" "calculations",
And what ever else a book says will work.
And what usually happens? They don't work. What works on paper, or even a dyno, might not happen going down the track.

This!!!!! ^^^^^^^^^^^^^^^^ I could care less about theory. I just want something that works and there has been a lot of good advice here given by people who have been there and done that!


The end is near.....
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