Mark,
I can see that my understanding is some different, so I'll write my thinking
and the experts can set us both straight..:0)

1. The fuel pressure regulator serves to relieve pressure when it goes over
a certain pressure.  Nominal pressure should be >33 and <41.  Mine is around
35psi on the EIS gauge but measured 40 on a test gauge.  This pressure
should remain relatively stable with a constant pressure feeding the
injectors (maximum 40psi in the cars)
2.  The vacuum connection gives a reference to the regulator and causes it
to lower fuel pressure 5-7 psi with lower manifold pressure,
3. The EC2 adjusts injector duty cycle and mixture as needed.
Regards,
Tommy James<><

-----Original Message-----
From: Mark Steitle [mailto:msteitle@mail.utexas.edu]
Sent: Thursday, October 02, 2003 1:22 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Fuel Pressure Regulators


Can someone explain why its recommended (by Tracy) to use a fuel pressure
regulator with the manifold vacuum port.  I understand that the vacuum port
causes a change in fuel pressure as the manifold pressure changes, but I
don't understand why we want the pressure to change.  This seems like it
would make it more difficult to tune the EC-2.  What am I missing here?

Also, what is the preferred fuel pressure for a n/a injected rotary?  (I
recall Ed Anderson stating he runs 45psi... Is this correct Ed).
Mark S.


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