craig pete errol etc
attached is some C code which solves the fluid dynamics relations
for diameter of fuel hose required to deliver a user supplied fuel flow
rate, over a user supplied fuel hose length, with a user defined
tolerable pressure drop.
flow rate, length and pressure drop allowable are inputted by
changing the #define values near the top. just change your values,
save then compile and run.
I hope everyone/anyone who is interested has a C compiler - sorry
but its easier to do such iterative calcs with C.
the calcs assume no bends or height changes, but these shouldnt
have too much affect seeing as such flow theory is only about +/-
10% accurate anyway (i could include their effects if anyone really
cares).
if anyone has problems/queries with the program or cant compile C
just email me and I can always input their desired variables in and
email the results back..........
andrew
From: "Pete & Kath Liebig" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Date sent: Mon, 1 Jan 2001 21:11:01 +1030
Send reply to: [EMAIL PROTECTED]
Subject: RE: FJ Fuel line advice needed
> Craig,
>
> Sounds fair. Next time I'm fiddling with the fuel system I'll do some
> experimenting.
>
> I still reckon 1/4" lines would be OK though - at 6.35mm that's still 1.35mm
> larger than the pump outlet, so hopefully that would allow enough for
> frictional losses. Only one way to find out though....
>
> By the way, I did some testing when I installed the new pump and came to the
> conclusion that one of the most important things to watch out for is voltage
> drop. Make sure the pump is getting close to it's full 12 volts or flow
> drops off markedly... I have the figures if you're interested.
>
>
> PL
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]] On Behalf Of Craig Overend
> Sent: Monday, 1 January 2001 17:28
> To: [EMAIL PROTECTED]
> Subject: Re: FJ Fuel line advice needed
>
> Pete,
> one thing to remember is depending on how long the fuel line is, you
> will see a pressure loss at the outlet end of the line. Just try blowing
> through a short and long piece of same ID hose and you'll definately
> notice the difference. So just because the pump will flow 250kW through
> its outlet doesnt necessarily mean a line X metres long with the same
> internal diameter or slightly bigger will flow the same. Using a line
> that is small may flow enough for the engine but is more likely to
> overload the fuel pump and overheat/wear it out causing failures.
>
> To do it properly you would do all the fluid mechanics maths, however
> alternativly try the following, I have not tested this method as I just
> came up with it, I havn't allowed for pump efficiency but the following
> might work.
>
> Measure the pump current using an ammetre when loading the pump up to
> the required pressure using the pressure regulator directly at its
> outlet. Then install the pump on the fuel line and regulator at the fuel
> line output and measure the current using the regulated pressure. You
> should then be able to tell if the pump is being overloaded from the
> current difference and calculate what % bigger flow rate of line you
> need.
> Say at 12V the pump consumes 7.5A at 60psi with no fuel line.
> Say at 12V the pump consumes 10.0A at 60psi with 5mm fuel line 3 metres
> long.
> Ratio difference = 10.0A/7.5A = 1.333
> The flow area of 5mm diam line = 5mm X 5mm / 4 * 3.142 = 19.637mm�
> 19.637mm� * 1.333 = 26.177mm�
> Square_root(26.177mm� / 3.142 * 4) = 5.773mm
> So Using a 5.773mm diameter line the pump will be much happier with more
> flow potential and last longer at 60psi.
> You could alternativly use the fuel pressure difference from the pump
> outlet to the fuel line outlet to calculate the % bigger flow rate
> required.
> Any comments welcome.
>
> With any EFI conversion you should test it using a fuel pressure gauge
> at the outlet of the line after you install it.
>
> Craig.
>
>
> Pete & Kath Liebig wrote:
> >
> > Bruce,
> >
> > The outlet on a Bosch EFI pump from the VL turbo is only 5mm in dia. And
> > these pumps will support up to 250Kw, so unless he intended getting more
> > than this from his engine then 1/4" lines should be fine. I know it seems
> a
> > bit small, but I really can't see any reason to go bigger than the pump
> > outlet. Pump inlet dia is another story...
> >
> > PL
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED]] On Behalf Of Bruce Ferguson
> > Sent: Friday, 29 December 2000 20:35
> > To: [EMAIL PROTECTED]
> > Subject: FJ Fuel line advice needed
> >
> > List,
> >
> > A young bloke I saw at the wreckers today wanted a
> > 1600 fuel line for his FJ conversion. (I was securing
> > a set of ventilated rotors and twin spots)
> >
> > I advised him that it was not big enough and 5/16" was
> > more on the mark. Was my advise correct and what about
> > the return line dia ?? the same ????
> >
> > Cheers
> >
> > Bruce
> >
> > __________________________________________________
> > Do You Yahoo!?
> > Yahoo! Photos - Share your holiday photos online!
> > http://photos.yahoo.com/
> >
>
>
>
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flow.c
