Mailing List flyrotary@lancaironline.net Message #15773
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Re: Fuel Injector Sizing
Date: Sat, 22 Jan 2005 11:11:23 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message
Thanks for the confirmation, Tracy.  That was my understanding - which indicates my manifold-referenced pressure regulator - Ain't.  Could be why I find the default fuel MAP setting a tad rich at lower manifold pressure (idle).
 
Ed A
----- Original Message -----
Sent: Saturday, January 22, 2005 10:38 AM
Subject: [FlyRotary] Re: Fuel Injector Sizing

Yes, the [gauge] pressure measured at the fuel rail should vary with manifold pressure.  Things will still work if this doesn't happen but the EC2 may run out of range in Mode 1 or 9 and it definitely makes tuning the EC2 much more difficult if the regulator isn't responding to manifold pressure changes.  This is especially true at the low end of MAP range.
 
Tracy

You certainly could be right about that, Rusty.  My understanding was to expect the fuel pressure to vary to compensate for the different manifold pressure.  But, there is no indication on my gauge and this is the second pressure regulator (but, of the same make Hmmm) that I have had.  It does regulate (else my fuel pressure would be much higher) but apparently does not compensate for manifold pressure based on what I am hearing.
 
  But, as you indicated, If there is any operational problem associated with it, I have not encountered it (or recognized it as such).  It is one of the smaller ones and it could be that it is dumping all the fuel it can at 40-43 psi and there is not sufficient return flow capacity to compensate for the variations in manifold pressure.  I suspect that if I had a turbo where the manifold pressure varied considerably that the lack of such compensation might be more detrimental to engine performance (and life).   Just speculation of course.
 
Ed A
 
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