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From: Lehanover@aol.com
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Date: Fri, 17 Sep 2004 02:19:11 EDT
Subject: Re: [FlyRotary] fuel lines
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In a message dated 9/16/2004 8:47:24 PM Central Daylight Time, 
frmrjohn@netonecom.net writes:

<< Ken;  Wicks has a facet fuel pump 0.8 amp, 12v, 30-35 gph,4.5 to 6# with
 3/8" 37 degree flare fittings.  FP40108.  Is this a good choice to feed the
 48 weber?  I have a gascolator to install after the fuel tank, with a screen
 in the fuel tank.  I'm collecting the hardware to install the weber 48 on a
 top over manifold that I purchased from Atkins.  JohnD
 --- >>

The only Facet pumps I have seen are interrupter style pumps. Where a steel 
piston is pulled up against a spring and released to make pressure. In some 
cases the piston has a one way ball valve in it, and in some cases the piston is 
just used as a displacement device. As far as I know, there is no contact set 
in these, and they use An inductance change caused by the moving slug to 
trigger an SCR to energize the coil. There are also interrupter pumps that have a 
diaphragm and a spring to do the same thing. You can tell if you have this type 
of pump, because once fuel pressure is achieved, the pump stops running until 
some fuel is consumed or a leak develops and the pressure in front of the 
pump drops. Then the pump will cycle a few times until pressure is restored. This 
style of pump has electrical contacts inside it and a diaphragm that will 
eventually leak, Trust me on this. 

I use two carter sliding vane pumps in parallel then a Holley fuel pressure 
regulator set at 6 PSI. The pumps are the 7 PSI street pumps. I have a Mallory 
fuel pressure isolator so that there is no pressurized fuel line in the car, 
in the event of a gage failure (we had that happen).

It would never come up in your application, but we look for 6 PSI at Max 
revs, as the Rotary tends to empty the float bowl at top revs (9,600 RPM). The 
engine still goes a hint lean above 8,400 RPM. I have the metal throw away "in 
line filter" in front of each pump to keep foam swarf out of them and a single 
large filter after the pumps. I have replaced one Carter since 1980. It wore 
out, and cannot hold 6 PSI anymore. I loan it out to other racers at the track. 
Piston engines don't use much fuel pressure so it works fine for them.  

I tune for 1510 to 1550 at 8,000 RPM. That is about 12.6 to 12.8 to one Fuel 
air ratio.

Once you have it running to your liking, you can lean it up to 1,650 EGT, and 
you can go leaner still, but the apex seals will be less happy with you. 


If you cannot hold the EGT at WOT you might want to go to a 3.5 or 4.0 Gross 
jet.
The Weber float jet will not flow enough fuel for a long pull at top revs and 
then it becomes the main jet for both sides no matter what main jet you have 
installed.
Also, there may be a little bug screen under a brass cap above the float jet. 
Throw that screen away. The screen is so fine that it plugs up regularly even 
with three filters in front of it. Also if it still leans out at the top. 
Drill the hole through the center of that screen mount to about twice what it is, 
and round over the edges of the drilling for good flow. Drill the brass cover 
nut and safety it. There may be a bowl drain. Another brass plug. Safety it 
as well. 

I have a dyno sheet for a bridgeported 12A at 6,500 RPM showing 173.3 HP at 
.666 BSFC. And 218.2 at 7,500 RPM .673 BSFC.

The 13B would be stronger without much work.

You can find everything you need in the Summit Racing catalog. 1-800-230-3030.


Lynn E. Hanover