Re: how much hp will 3/8 fuel line handle?
[Re: VanishPt]
#605002
02/06/10 04:07 PM
02/06/10 04:07 PM
|
Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
|
Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
|
Quote:
3/8 "is the outside diameter. The inside is @1/4"
the inside is 5/16" on a 3/8" steel line
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: IcorkSOAK]
#605003
02/06/10 04:13 PM
02/06/10 04:13 PM
|
Joined: Aug 2009
Posts: 87 Denmark
Dart of Denmark
member
|
member
Joined: Aug 2009
Posts: 87
Denmark
|
Quote:
Quote:
The larger the hose diameter the less friction loss given the same hose length and discharge pressure.
Sometimes it does
B U T ....a fire-hose is that traveling from a dead-stop to 60 mph in 2 seconds or so !
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: dizuster]
#605004
02/06/10 05:22 PM
02/06/10 05:22 PM
|
Joined: May 2008
Posts: 1,131 Thigh-Gap Junction
@#$%&*!
New user name, Same old jerk!
|
New user name, Same old jerk!
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
|
Quote:
Ok, lets do some math...
... Take the 3/8" diameter So 3.1415 x .375"^2 x 100"x .0267lbs/in^3= 1.17 lbs mass
1. Area = pi*D^2/4, your volume calculations are 4X too big. 2. You're using solid mechanics math on a fluid mechanics problem. Quote:
There are two separate issues and some are confusing them. One is the acceleration of a fluid and I've explained that one previously, the size of the line isn't an issue. The other is the pressure loss from fluid flow through the lines and fittings. This is the area people should focus on. First find your actual max. flow rate and then calculate the velocity in the line and determine if you need a bigger line. See this page: http://en.wikipedia.org/wiki/Reynolds_number
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: IcorkSOAK]
#605006
02/06/10 07:04 PM
02/06/10 07:04 PM
|
Joined: Feb 2003
Posts: 1,646 Ontario,Canada
firefighter3931
top fuel
|
top fuel
Joined: Feb 2003
Posts: 1,646
Ontario,Canada
|
Quote:
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 !
I guess you're missing the point Doc ? You're a Doctor of What ? Fiberglass ?
Fact is, the larger the diameter the less the friction loss is. A 1.5in line loses 25psi pressure per 100ft. A 2.5in line loses 14psi. A 4in line loses 4 psi....and so on.
A 5/16 line will have more friction loss than a 3/8in line....all things being equal. The velocity of the fluid has little to do with it....surface contact has everything to do with it. The larger the percentage of surface contact vs the total volume of fluid....the greater the friction loss.
All this is academic anyway....i agree that a 3/8-1/2 line is plenty for just about any application
Ron
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: DaveDudek]
#605008
02/06/10 09:36 PM
02/06/10 09:36 PM
|
Joined: Apr 2005
Posts: 673 Emmett, Idaho
SuperStockWagon
mopar
|
mopar
Joined: Apr 2005
Posts: 673
Emmett, Idaho
|
Quote:
I have one stock 5/16 fuel line feeding both carbs. [Email]10.35@134.4[/Email] and 770HP on the dyno..
Thats all I need know! Thanks Dave!
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: SuperStockWagon]
#605009
02/06/10 10:28 PM
02/06/10 10:28 PM
|
Joined: May 2008
Posts: 1,131 Thigh-Gap Junction
@#$%&*!
New user name, Same old jerk!
|
New user name, Same old jerk!
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
|
Quote:
Quote:
I have one stock 5/16 fuel line feeding both carbs. [Email]10.35@134.4[/Email] and 770HP on the dyno..
That's all I need know! Thanks Dave!
Those numbers make me have questions. The ET is about 1/2-second slow for the speed and the speed/hp relationship only works if the car weighs like 4150-lbs. There are a lot of possible explanations for all this but one is a car that falls on its face at 900-1000 feet due to fuel starvation.
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: @#$%&*!]
#605011
02/06/10 11:14 PM
02/06/10 11:14 PM
|
Joined: Jan 2003
Posts: 5,875 communist bloc of new jersey
jamesc
master
|
master
Joined: Jan 2003
Posts: 5,875
communist bloc of new jersey
|
Quote:
There are a lot of possible explanations for all this but one is a car that falls on its face at 900-1000 feet due to fuel starvation.
it's a FAST car...quite literally
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: jamesc]
#605014
02/07/10 12:18 AM
02/07/10 12:18 AM
|
Joined: Aug 2003
Posts: 43,909 Bend,OR USA
Cab_Burge
I Win
|
I Win
Joined: Aug 2003
Posts: 43,909
Bend,OR USA
|
Can anyone on here verify if the fluid dynamics theory are based on stationary commercial applications? I'm thinking, that if that is so, then they, it, does not apply to fluid systems mounted onto accelerating vehicle like race cars, race boats, airplanes and rocket ships
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: Cab_Burge]
#605015
02/07/10 12:40 AM
02/07/10 12:40 AM
|
Joined: May 2008
Posts: 1,131 Thigh-Gap Junction
@#$%&*!
New user name, Same old jerk!
|
New user name, Same old jerk!
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
|
Define "stationary', really, it's not as easy as you think. They say that the only truly stationary 'object' is the center of the universe, and that everything is moving away from it. Effectively, nothing is stationary and all motion is relative. The equation relating pressure of a column of fluid is from hydrostatics, absolutely. But that gravity is included means that an acceleration is involved, 32.2 ft/second^2. The more general form uses acceleration instead of gravity, any acceleration. A similar situation occurs with weight. Weight is just the force that results from a mass under the acceleration of gravity. Accelerate your car at 1G and the reaction force opposite your direction of travel equals the weight of the car/driver. Quote:
Can anyone on here verify if the fluid dynamics theory are based on stationary commercial applications? I'm thinking, that if that is so, then they, it, does not apply to fluid systems mounted onto accelerating vehicle like race cars, race boats, airplanes and rocket ships
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: DaveDudek]
#605017
02/07/10 01:05 PM
02/07/10 01:05 PM
|
Joined: Oct 2008
Posts: 506 Utah, USA
1964superstock
mopar
|
mopar
Joined: Oct 2008
Posts: 506
Utah, USA
|
Quote:
I have one stock 5/16 fuel line feeding both carbs. [Email]10.35@134.4[/Email] and 770HP on the dyno..
Dave
I am curious about the fuel system combo in your awesome '69 Roadrunner. I am sure there are many others who would be interested, and helped with your advise on this issue.
1) What fuel pump are you using with the stock 5/16" fuel line?
2) Where is the fuel pump located?
3) What size fuel pickup are you using in the gas tank?
4) Are you using a fuel pressure regulator?
Thanks.
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: @#$%&*!]
#605018
02/08/10 05:24 AM
02/08/10 05:24 AM
|
Joined: Dec 2007
Posts: 486 IL
knyech1
mopar
|
mopar
Joined: Dec 2007
Posts: 486
IL
|
Quote:
Quote:
Can anyone on here verify if the fluid dynamics theory are based on stationary commercial applications? I'm thinking, that if that is so, then they, it, does not apply to fluid systems mounted onto accelerating vehicle like race cars, race boats, airplanes and rocket ships
Define "stationary', really, it's not as easy as you think. They say that the only truly stationary 'object' is the center of the universe, and that everything is moving away from it. Effectively, nothing is stationary and all motion is relative. The equation relating pressure of a column of fluid is from hydrostatics, absolutely. But that gravity is included means that an acceleration is involved, 32.2 ft/second^2. The more general form uses acceleration instead of gravity, any acceleration. A similar situation occurs with weight. Weight is just the force that results from a mass under the acceleration of gravity. Accelerate your car at 1G and the reaction force opposite your direction of travel equals the weight of the car/driver.
Hmmmmm, most basic fluid dynamics equations seem leave gravity out I was told for what we did it was not really necessary....The fact that everything has an inward angular acceleration (or "rotates" as most say) from the gravitational pull of the sun really has little effect on anything. One can consider an object stationary if it is sitting on the earth with no velocity, the motions of the earth relative to the object you are examining have such a minimal effect that they need not be taken into consideration. As far as the 1G thing goes it sounds like you are saying that if I were to accelerate at 32.2ft/s^s in the positive x-dir the weight of the car plus me would be on my in the negative x-dir. Pretty crushing force. As you sit on your computer right now you are opposing 1G, defined by Newton's Second Law, F=ma; F being basically what you see when you hop up on the scale in your bathroom, it IS your weight. I am 160lb, so if I were to accelerate at 32.2ft/s^2 that would be a 2G force, and the force acting on my body would be 320lb-force downward onto my seat, and as Newton's Third Law explains, the seat would react with a force equal in magnitude and opposite in direction, making you feel the force being put upon you.
knyech1-
'71 Sassy Grass Demon 340/904. Pump gas, 1.61 60ft, 7.439 1/8 @ 95mph, 11.824 1/4 @ 111mph
"Not too bad for a pump gas 340, full of used parts and hillbilly ported stock heads." - V.B.
'03 2500 5.9L HO 6-spd on 35's. 395hp/755ft-lb at tires.
|
|
|
Re: how much hp will 3/8 fuel line handle?
[Re: knyech1]
#605019
02/08/10 12:31 PM
02/08/10 12:31 PM
|
Joined: Jan 2005
Posts: 3,640 Oakland, MI
dizuster
master
|
master
Joined: Jan 2005
Posts: 3,640
Oakland, MI
|
Exactly. I just don't see why you think the mass of the fuel can be ignored. (not you Kny')
Look at it this way, if you throw a cup full of water towards the air, the water continues upward (despite being under 14.7 psi of pressure from the atmosphere). Then the water comes back down, because the mass is being affected by gravity (acceleration). The water is still at 14.7psi through the entire situation, but the external forces on the way up, and the gravitational forces on the way down, still have an effect.
6psi is just gauge pressure, which is really 20.7psi actual, but it's all acting the same way.
|
|
|
|
|