Fuel pressure / Flow rate formula

[David A. Cooley]

The problem lies not in pumping the pressure up, but the rated max
operating pressure of the injector...
You crank up the FP too far past the rated pressure (in your case 40psi)
and 1 of 2 things happen... the injector gets held open by the fuel
pressure, or it refuses to open because of the excessive pressure.
The safest and most reliable route is find an injector that flows what you
need in it's rated capacity.  Overpressure kills them.


At 04:17 PM 11/12/98 -0700, you wrote:
>What's the formula for figuring out the flow rate of an injector if you
>bump up the fuel pressure?  I've found 2 different ones that give *huge*
>differences in the result.
>
>The first is from an MSD fuel management catalog/brochure I have.  It
>states that 
>
>
>F2 = sqrt(P2 / P1) * F1
>
>
>For me, I have a 20 lb injector at 40 psi and I want to check the flow
>at a maximum of 70 psi, so
>
>F2 = sqrt(70 / 40) * 20  =  26.4 lbs/hr
>
>
>Not as much as I had hoped.
>
>I then found a different formula on the RC engineering page 
>http://www.rceng.com/technical.htm.  It's almost the same, except that it
>uses a strait ratio between the pressures instead the square root of them,
>so according to them, I have:
>
>
>F2 = (70 / 40) * 20  =  35 lbs/hr
>
>
>
>This is a very large difference.  Which one is right?
>
>
>thanks
>--Dan
> 
===========================================================
           David Cooley N5XMT           Internet: N5XMT at bellsouth.net
     Packet: N5XMT at KQ4LO.#INT.NC.USA.NA   T.A.P.R. Member #7068
       I am Pentium of Borg...division is futile...you will be approximated.
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