What
fuel pressure range should I be seeing for a Lycoming IO-360 in a
Lancair 360
(N360DE)?
The
fuel pressure is indicating between 16 and 18 without the boost pump
on.
When I go to altitudes above 6,000 feet, the fuel pressure drops a
pound
or two so I turn on the boost pump. With the boost pump on fuel
pressure
in indicated between 18 and 20 PSI.
What is
interesting is that the VM 1000 (where Fuel Pressure is indicated) has
a red
arc section, a yellow arc section, and a green arc section. At the
fuel
pressures I am seeing; 16 PSI is in the top end of the yellow arc, so
17 to 20
PSI appears in the lower range of the green arc – giving us the feeling
that we are on the ragged edge of not having proper fuel pressure for
normal
operation.
The
VM-1000 can be calibrated so that the proper fuel pressure indicates
more
properly in the green arc – if this is proper.
Information
that may be important to know:
IO-360
Model = Started
life as
O-360-C2A and converted to an IO-360 – S/N L-21393-36A
Fuel
pressure is taken after the
mechanical pump,
1 foot before the fuel servo on a tee fitting.
Fuel
system/model/etc. = Bendix,
model RSA 5AD1,
parts list 2524213-10 less issues -11, S/N 9354/10
Have
any
components (fuel pump, servo, flow-divider,
nozzles, etc.) been modified? = Fuel servo mod: there was a mod made to
the servo fuel
injector to reverse the actuation of the butterfly valve and the
fuel-metering
valve. When the throttle arm was rotated full forward; this was the
idle
position of the butterfly valve and the fuel-metering valve. We had
this
reversed so that full forward position resulted in full throttle.
No other mods.
What type
mechanical (engine-driven) fuel pump (diaphragm or rotary)? = Diaphragm
Thanks in advance.
Randy Hartman