X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from ms-smtp-01.southeast.rr.com ([24.25.9.100] verified) by logan.com (CommuniGate Pro SMTP 5.1c.4) with ESMTP id 1414955 for flyrotary@lancaironline.net; Fri, 22 Sep 2006 09:02:38 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.100; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-100-038.carolina.res.rr.com [24.74.100.38]) by ms-smtp-01.southeast.rr.com (8.13.6/8.13.6) with SMTP id k8MD1h8I002184 for ; Fri, 22 Sep 2006 09:01:45 -0400 (EDT) Message-ID: <002001c6de47$6b014f10$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Fuel Pressure Regulator Vacuum or Boost?? Date: Fri, 22 Sep 2006 09:02:54 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001D_01C6DE25.E3A5D4D0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2962 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_001D_01C6DE25.E3A5D4D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks, Al. I was not certain that the EC2 was set up for a manifold = referenced regulator - but, I suspected it was especially seeing that = the default MAP settings at idle always turned out to be too rich for my = engine. My fault for assuming that "Boost referenced" meant also = "vacuum referenced". So that completes the equation. The EC2 is manifold referenced so for = best fuel control the pressure regulator should be "vacuum referenced". = Boost referenced also if you have forced induction. Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://members.cox.net/rogersda/rotary/configs.htm#N494BW ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Thursday, September 21, 2006 11:14 PM Subject: [FlyRotary] Re: Fuel Pressure Regulator Vacuum or Boost?? Ed; I started with a fixed pressure regulator at 42-43#, which would = normally be fine for NA. When I was having trouble getting the engine = to idle right with Tracy's EC2; he mentioned that his programming was = set up assuming a manifold pressure referenced regulator. TWM was kind = enough to trade me straight across for one that was pressure referenced = - pressure at idle now is low 30's, and it helped getting good idle. I guess "boost referenced" means just that; for MAP above normal = atmospheric. Al -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Ed Anderson Sent: Thursday, September 21, 2006 9:58 AM To: Rotary motors in aircraft Subject: [FlyRotary] Fuel Pressure Regulator Vacuum or Boost?? For the entire life of my rotary powered RV-6A, I have flown with a = "Boost Referenced" adjustable fuel pressure regulator from MSD. As you = know, it is desirable to keep the pressure differential between the = injector fuel rail pressure and the manifold pressure a constant for = best fuel injection control. =20 I flew for several years thinking that since my pressure regulator was = manifold reference that it was indeed doing this. Then the light bulb = came on - my fuel pressure holds rock-steady at 43 PSI - and does not = vary between idle and WOT! This certainly implies that the fuel = pressure IS NOT varying as a function of manifold pressure. Then doing some recent research on fuel pressure regulators, I noticed = that some say they are "Boost Referenced" and other's say "Vacuum/Boost = Referenced". My conclusion (which may be incorrect) is that while my = pressure regulator is "Boost Referenced" it is not "Vacuum Referenced". = The difference (If I understand it correctly ) is that my regulator = would increase fuel pressure IF it ever encounter manifold pressure = greater than ambient - since I am not used forced induction that never = happens - which in turn appears to be the reason I never see the fuel = pressure changing in response to manifold "vacuum". So my question to those who realllllllyyyyyy know - is it correct = that for my NA 13B I need a fuel pressure regulator that responses to = manifold "Vacuum" or is the difference in description between "vacuum = referenced and boost referenced " just semantics in advertising? Thanks Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://members.cox.net/rogersda/rotary/configs.htm#N494BW ------=_NextPart_000_001D_01C6DE25.E3A5D4D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks, Al.  I was not certain that the EC2 = was set=20 up for a manifold referenced regulator - but, I suspected it was = especially=20 seeing that the default MAP settings at idle always turned out to be too = rich=20 for my engine.   My fault for  assuming that "Boost=20 referenced" meant also "vacuum referenced".
 
So that completes the equation.  The EC2 is = manifold=20 referenced so for best fuel control the pressure regulator should be = "vacuum=20 referenced".  Boost referenced also if you have forced=20 induction.
 
Ed
 
Ed Anderson
Rv-6A N494BW Rotary = Powered
Matthews,=20 NC
eanderson@carolina.rr.comhttp:/= /members.cox.net/rogersda/rotary/configs.htm#N494BW
----- Original Message -----
From:=20 Al = Gietzen=20
Sent: Thursday, September 21, = 2006 11:14=20 PM
Subject: [FlyRotary] Re: Fuel = Pressure=20 Regulator Vacuum or Boost??

Ed;

 

I started = with a=20 fixed pressure regulator at 42-43#, which would normally be fine for = NA.=20  When I was having trouble getting the engine to idle right with=20 Tracy=92s EC2; = he=20 mentioned that his programming was set up assuming a manifold pressure = referenced regulator.  TWM was kind enough to trade me straight = across=20 for one that was pressure referenced =96 pressure at idle now is low = 30=92s, and=20 it helped getting good idle.

 

I guess = =93boost=20 referenced=94 means just that; for MAP above normal=20 atmospheric.

 

Al

 

-----Original=20 Message-----
From: = Rotary=20 motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed = Anderson
Sent: Thursday, September 21, = 2006 9:58=20 AM
To: Rotary = motors in=20 aircraft
Subject: = [FlyRotary]=20 Fuel Pressure Regulator Vacuum or Boost??

 

For the entire life of = my rotary=20 powered RV-6A, I have flown with a "Boost Referenced" adjustable fuel = pressure=20 regulator from MSD.  As you know, it is desirable to keep the = pressure=20 differential between the injector fuel rail pressure and the manifold = pressure=20 a constant for best fuel injection control.  =

 

I flew for several years = thinking=20 that since my pressure regulator was manifold reference that it was = indeed=20 doing this.  Then the light bulb came on - my fuel pressure holds = rock-steady at 43 PSI - and does not vary between idle and WOT!  = This=20 certainly implies that the fuel pressure IS NOT varying as a function = of=20 manifold pressure.

 

Then doing some recent = research on=20 fuel pressure regulators, I noticed that some say they are "Boost = Referenced"=20 and other's say "Vacuum/Boost Referenced".   My conclusion = (which=20 may be incorrect)  is that while my pressure regulator is "Boost=20 Referenced" it is not "Vacuum Referenced".  The difference (If I=20 understand it correctly ) is that my regulator would increase fuel = pressure IF=20 it ever encounter manifold pressure greater than ambient - since I am = not used=20 forced induction that never happens - which in turn appears to be the = reason I=20 never see the fuel pressure changing in response to manifold=20 "vacuum".

 

So my question to those = who=20 realllllllyyyyyy know -  is it correct that for my NA 13B I need = a fuel=20 pressure regulator that responses to manifold "Vacuum" or is the = difference in=20 description between "vacuum referenced and boost referenced " just = semantics=20 in advertising?

 

Thanks

 

Ed

 

Ed Anderson
Rv-6A = N494BW Rotary=20 Powered
Matthews, NC
eanderson@carolina.rr.comhttp:/= /members.cox.net/rogersda/rotary/configs.htm#N494BW

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