Re: how much hp will 3/8 fuel line handle?
[Re: B3422W5]
#604980
02/06/10 06:03 AM
02/06/10 06:03 AM
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Joined: Jan 2003
Posts: 5,875 communist bloc of new jersey
jamesc
master
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master
Joined: Jan 2003
Posts: 5,875
communist bloc of new jersey
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Quote:
i think most 9-11 second car owners on this board must own stock in magnafuel, as they all seem to run their 1200-1500 dollar setups on cars that in no way need them( na)
yea but they look purty
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Re: how much hp will 3/8 fuel line handle?
[Re: Ron Silva]
#604982
02/06/10 08:26 AM
02/06/10 08:26 AM
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Joined: Mar 2006
Posts: 5,067 Orlando Florida
blown572dart
master
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master
Joined: Mar 2006
Posts: 5,067
Orlando Florida
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Quote:
Quote:
Yet ANOTHER fuel-line topic ...
And a 3/8 line will handle THE FASTEST car on this board.
That's why I have a 1/2" line on my car!
I guess I used the wrong size line because mines 1 1/4
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Re: how much hp will 3/8 fuel line handle?
[Re: Crizila]
#604984
02/06/10 08:55 AM
02/06/10 08:55 AM
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Joined: Jul 2008
Posts: 30,632 Florida STAYcation
IcorkSOAK
Financed his waterbed
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Financed his waterbed
Joined: Jul 2008
Posts: 30,632
Florida STAYcation
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Quote:
Going lean in the lights can cost you more than most fuel systems.
B U T ...a quick-check of the function of your fuel-system with a simple fuel-pressure gauge will save you the uNnecessary time and expense of doing work that is not really needed.
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Re: how much hp will 3/8 fuel line handle?
[Re: maximum entropy]
#604985
02/06/10 09:14 AM
02/06/10 09:14 AM
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Joined: Jan 2003
Posts: 10,154 Frostbitefalls MN (Rocky&Bullw...
gregsdart
I Live Here
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I Live Here
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Posts: 10,154
Frostbitefalls MN (Rocky&Bullw...
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Quote:
i have 3/8 at 650 hp, with a carter mechanical race pump. my pressure gauge hardly drops at all during a run, so i couldn't tell you how close i am to the limit w/my combo. put a fuel pressure gauge in it. then you know.
The only true test is watching the gauge throughout a run. If it will hold the same PSI start to finish, you are good to go. On fuel line size , so many variables come in to play, it is very difficult to put a hp number to any particular fuel line size. Length of the line, number of bends, G force, pump pressure and any variance in voltage will change the rate of flow. So the real answer is "it depends". The end result needs to be will there be enough fuel delivery to keep the bowls at the same level at all times. That is a lot easier with four needle and seats on a tunnelram/dual four combo. A high hp dominater is one of the toughest to feed. Only two needle and seats, and often lots of hp.
8.582, 160.18 mph best, 2905 lbs 549, indy 572-13, alky
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Re: how much hp will 3/8 fuel line handle?
[Re: jamesc]
#604987
02/06/10 12:28 PM
02/06/10 12:28 PM
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Joined: Aug 2003
Posts: 550 Camp Point, IL
gofish
mopar
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mopar
Joined: Aug 2003
Posts: 550
Camp Point, IL
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For gas, 3/8 could handle over 1000 HP if the fuel cell is mounted in the front of the engine. Alcohol is a different story. Too big of a fuel line can be a problem if the cell and pump are in the back of the car and the car leaves extremely hard and the pump isn't strong enough handle the load of the fuel and g-forces.
Danny
Last edited by gofish; 02/06/10 12:38 PM.
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Re: how much hp will 3/8 fuel line handle?
[Re: gofish]
#604988
02/06/10 12:43 PM
02/06/10 12:43 PM
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Joined: Jan 2003
Posts: 6,531 Jacksonville, FL
Chris2581
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Jacksonville, FL
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FWIW....Bob Lambeck's 68 Dart was run as a Pro Stocker in 1971.It had a Carter mechanical fuel pump in front with a electric pump in the rear with 3/8th's line and he was running 9.70's with that car.If it worked then,it will work today.
Nautilus Racing- We use Superformance gaskets and Turbo Action converters/products.
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Re: how much hp will 3/8 fuel line handle?
[Re: gofish]
#604989
02/06/10 12:52 PM
02/06/10 12:52 PM
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Joined: May 2008
Posts: 1,131 Thigh-Gap Junction
@#$%&*!
New user name, Same old jerk!
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New user name, Same old jerk!
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
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Quote:
...Too big of a fuel line can be a problem if the cell and pump are in the back of the car and the car leaves extremely hard...
One of my Mopar manuals has a line about fuel line diameter and acceleration and it's totally wrong. I'm pretty sure they deleted it from later manuals. To reiterate: the pressure generated from accelerating a column of fluid is independent of the area of the column (or in this case, the diameter of the fuel line). The pressure generated is the product of the fluid density, acceleration rate, and the height/length of the fluid parallel to the direction of acceleration. Cross sectional area doesn't figure in at all. For instance, the pressure 50' below the surface of Lake Superior is the same as the pressure 50' below the surface of lake Huron, even though one has a much larger area. Let's put this myth out of its misery.
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Re: how much hp will 3/8 fuel line handle?
[Re: Cab_Burge]
#604990
02/06/10 01:18 PM
02/06/10 01:18 PM
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Joined: May 2008
Posts: 1,131 Thigh-Gap Junction
@#$%&*!
New user name, Same old jerk!
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New user name, Same old jerk!
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
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Cab, when using the 'Quote' feature you need to pay attention to the "quote" and "/quote" markers so you don't get people's quotes mixed up with your replies. I've corrected your reply in attempt to straighten it out. The test I proposed is a type of load test, where the pressure is measured WHILE the system is flowing. In this way pressure losses across lines and fittings are accounted for (the ones before the regulator anyway). I can also measure flow rate at the same time. I can guarantee you that if there is no pressure shown across the needle/seat under full flow that there is a big enough pump to change that. The whole point is to determine if the pump/filter/lines/fittings/etc are more than adequate to supply a pair of .120" needle assemblies mounted in standard Holley center-hung bowls. My system (Mallory 140, 1/2" line) flows 1 gallon in 25 seconds to the regulator and hauls my heavy '68 Barracuda to low 10's@ 129mph. At the end of last year I was running 60% ethanol but never got around to trying pure E85. I use an Innovate LM-2 wideband to tell me if the engine goes lean, and it hasn't. My combo liked the indicated AFR around 12:1 but wasn't very sensitive to AFR ET or MPH-wise in that neighborhood. Quote:
Quote:
The problem with this method (BG below) is it totally ignores the weight of the vehicle. Here's a test I plan to preform someday soon: Take fuel bowls off carb and put them in cans and turn on the fuel pump and see just how much the pressure drops at maximum float drop.
Fuel pressure has nothing to do with how much volume the system will support, if you do that test and you have any pressure at the gauge you need bigger fittings, lines or needles and seat
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Re: how much hp will 3/8 fuel line handle?
[Re: @#$%&*!]
#604991
02/06/10 01:52 PM
02/06/10 01:52 PM
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Joined: Jan 2005
Posts: 3,640 Oakland, MI
dizuster
master
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master
Joined: Jan 2005
Posts: 3,640
Oakland, MI
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Quote:
One of my Mopar manuals has a line about fuel line diameter and acceleration and it's totally wrong. I'm pretty sure they deleted it from later manuals. To reiterate: the pressure generated from accelerating a column of fluid is independent of the area of the column (or in this case, the diameter of the fuel line). The pressure generated is the product of the fluid density, acceleration rate, and the height/length of the fluid parallel to the direction of acceleration. Cross sectional area doesn't figure in at all. For instance, the pressure 50' below the surface of Lake Superior is the same as the pressure 50' below the surface of lake Huron, even though one has a much larger area. Let's put this myth out of its misery.
I'm not saying your wrong (because I can't find my fluids book)... But, I'm just thinking out loud here...
I think you're correct for a static condition, but doesn't the inertia from the weight of the entire fuel column come into play? Essentially if you think of the fuel in the fuel line as solid, the force generated back to the pump cavity (and thus the pump vane/motor) would be it's mass times horizonal acceleration. The larger the mass (Diameter), the more force is put on the pump vane to keep it all moving forward.
Like I said, not arguing, just thinking out loud.
What do you think?
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Re: how much hp will 3/8 fuel line handle?
[Re: dizuster]
#604992
02/06/10 01:56 PM
02/06/10 01:56 PM
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Joined: Jul 2008
Posts: 30,632 Florida STAYcation
IcorkSOAK
Financed his waterbed
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Financed his waterbed
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Posts: 30,632
Florida STAYcation
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Quote:
doesn't the inertia from the weight of the entire fuel column come into play? Essentially if you think of the fuel in the fuel line as solid, the force generated back to the pump cavity (and thus the pump vane/motor) would be it's mass times horizonal acceleration. The larger the mass (Diameter), the more force is put on the pump vane to keep it all moving forward.
Roger that ..... x 101 !
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Re: how much hp will 3/8 fuel line handle?
[Re: dizuster]
#604994
02/06/10 02:08 PM
02/06/10 02:08 PM
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Joined: Jan 2003
Posts: 5,875 communist bloc of new jersey
jamesc
master
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master
Joined: Jan 2003
Posts: 5,875
communist bloc of new jersey
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Quote:
What do you think?
the mechanics of fluids says NO.
fluids exert force in all directions, the diameter of the line has nothing to do with the pressure created by acceleration. yes it does seem to go against what one would "think" but the fact of the matter is the diameter doesn't come into play. the height (or in this discussion length) does.
Quote:
Let's put this myth out of its misery.
i bin tryin to but they just won't listen. worst part is barry grant's website has the same incorrect information.
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Re: how much hp will 3/8 fuel line handle?
[Re: @#$%&*!]
#604995
02/06/10 02:36 PM
02/06/10 02:36 PM
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Joined: Aug 2003
Posts: 43,909 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,909
Bend,OR USA
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Quote:
Cab, when using the 'Quote' feature you need to pay attention to the "quote" and "/quote" markers so you don't get people's quotes mixed up with your replies. I've corrected your reply in attempt to straighten it out. The test I proposed is a type of load test, where the pressure is measured WHILE the system is flowing. In this way pressure losses across lines and fittings are accounted for (the ones before the regulator anyway). I can also measure flow rate at the same time. I can guarantee you that if there is no pressure shown across the needle/seat under full flow that there is a big enough pump to change that. The whole point is to determine if the pump/filter/lines/fittings/etc are more than adequate to supply a pair of .120" needle assemblies mounted in standard Holley center-hung bowls. My system (Mallory 140, 1/2" line) flows 1 gallon in 25 seconds to the regulator and hauls my heavy '68 Barracuda to low 10's@ 129mph. At the end of last year I was running 60% ethanol but never got around to trying pure E85. I use an Innovate LM-2 wideband to tell me if the engine goes lean, and it hasn't. My combo liked the indicated AFR around 12:1 but wasn't very sensitive to AFR ET or MPH-wise in that neighborhood.
Quote:
Quote:
The problem with this method (BG below) is it totally ignores the weight of the vehicle. Here's a test I plan to preform someday soon: Take fuel bowls off carb and put them in cans and turn on the fuel pump and see just how much the pressure drops at maximum float drop.
Fuel pressure has nothing to do with how much volume the system will support, if you do that test and you have any pressure at the gauge you need bigger fittings, lines or needles and seat
thanks for pointing that out, deleting the quote marks I didn't read that reply until this morning
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: how much hp will 3/8 fuel line handle?
[Re: 67 GTX]
#604997
02/06/10 02:59 PM
02/06/10 02:59 PM
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Joined: May 2008
Posts: 1,131 Thigh-Gap Junction
@#$%&*!
New user name, Same old jerk!
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New user name, Same old jerk!
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
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Quote:
Where the diameter of the fuel line comes into play is the velocity of the fluid within the line. Head losses or pressure losses are related to velocity squared divided by 2 x force of gravity times the head loss coefficient of the tubing. So essentially a larger diameter tubing reduces the fuel velocity and the pressure losses.
The mass/inertia of the fluid does come into play, that's why the density is in the the equation. Area doesn't factor in at all.
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Re: how much hp will 3/8 fuel line handle?
[Re: 67 GTX]
#604998
02/06/10 03:15 PM
02/06/10 03:15 PM
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Joined: Feb 2003
Posts: 1,646 Ontario,Canada
firefighter3931
top fuel
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top fuel
Joined: Feb 2003
Posts: 1,646
Ontario,Canada
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Quote:
So essentially a larger diameter tubing reduces the fuel velocity and the pressure losses.
In firefighting Pump operations this is referred to as friction loss. The larger the hose diameter the less friction loss given the same hose length and discharge pressure.
Good discussion
My old 446 was using a 3/8 line with a Carter HV 120gph mechanical. The car ran 116mph @ 4100 raceweight...do the math.
The new 572 will be using 8an lines with a Mallory 250 and return style regulator. This motor made 705hp on Dwayne's dyno.
Ron
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Re: how much hp will 3/8 fuel line handle?
[Re: firefighter3931]
#604999
02/06/10 03:33 PM
02/06/10 03:33 PM
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Joined: Jul 2008
Posts: 30,632 Florida STAYcation
IcorkSOAK
Financed his waterbed
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Financed his waterbed
Joined: Jul 2008
Posts: 30,632
Florida STAYcation
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Quote:
The larger the hose diameter the less friction loss given the same hose length and discharge pressure.
B U T ....a fire-hose is that traveling from a dead-stop to 60 mph in 2 seconds or so !
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