X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from py-out-1112.google.com ([64.233.166.180] verified) by logan.com (CommuniGate Pro SMTP 5.1c.4) with ESMTP id 1413674 for flyrotary@lancaironline.net; Thu, 21 Sep 2006 14:07:15 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.233.166.180; envelope-from=barrygardner@gmail.com Received: by py-out-1112.google.com with SMTP id c31so908570pyd for ; Thu, 21 Sep 2006 11:06:35 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:from:to:references:subject:date:mime-version:content-type:x-priority:x-msmail-priority:x-mailer:x-mimeole; b=K7RHekZyYet5qx3W2Itzx9Qr9ozE2EWCwBETkM/AhqIIT2nhBEOONfsahfoVs0s1X9ubev4NjdiA/QuKPJ7F3Q3tYSTQi2nirRPVQrdhaxOQhGXy2AR/du5gODYQNCPhxm0PrIAc3Z/uaSyQoRfeI/oQ1pI0jqp37rpEJh9PQKY= Received: by 10.35.84.12 with SMTP id m12mr31363109pyl; Thu, 21 Sep 2006 11:06:35 -0700 (PDT) Return-Path: Received: from dellc400 ( [75.4.35.167]) by mx.gmail.com with ESMTP id i64sm838033pye.2006.09.21.11.06.34; Thu, 21 Sep 2006 11:06:34 -0700 (PDT) Message-ID: <027101c6dda8$ab2f0ef0$6601a8c0@dellc400> From: "Barry Gardner" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Fuel Pressure Regulator Vacuum or Boost?? Date: Thu, 21 Sep 2006 13:06:31 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_026E_01C6DD7E.C1A19DD0" 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 This is a multi-part message in MIME format. ------=_NextPart_000_026E_01C6DD7E.C1A19DD0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Ed, If stock automotive regulators don't take vacuum into account (to the = best of my knowledge, anyhow), is it important? Barry Gardner Wheaton, IL ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Thursday, September 21, 2006 12:57 PM 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_026E_01C6DD7E.C1A19DD0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Ed,
 
If stock automotive regulators don't = take vacuum=20 into account (to the best of my knowledge, anyhow), is it=20 important?
 
Barry Gardner
Wheaton, IL
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Thursday, September 21, = 2006 12:57=20 PM
Subject: [FlyRotary] Fuel = Pressure=20 Regulator Vacuum or Boost??

For the entire life of my rotary powered = RV-6A, I have=20 flown with a "Boost Referenced" adjustable fuel pressure regulator = from=20 MSD.  As you know, it is desirable to keep the pressure = differential=20 between the injector fuel rail pressure and the manifold pressure a = constant=20 for best fuel injection control. 
 
I flew for several years thinking that since = my pressure=20 regulator was manifold reference that it was indeed doing this.  = Then the=20 light bulb came on - my fuel pressure holds rock-steady at 43 PSI - = and does=20 not vary between idle and WOT!  This certainly implies that the = fuel=20 pressure IS NOT varying as a function of manifold = pressure.
 
Then doing some recent research on fuel = pressure=20 regulators, I noticed that some say they are "Boost Referenced" and = other's=20 say "Vacuum/Boost Referenced".   My conclusion (which may be = incorrect)  is that while my pressure regulator is "Boost = Referenced" it=20 is not "Vacuum Referenced".  The difference (If I understand it = correctly=20 ) is that my regulator would increase fuel pressure IF it ever = encounter=20 manifold pressure greater than ambient - since I am not used forced = induction=20 that never happens - which in turn appears to be the reason I never = see the=20 fuel pressure changing in response to manifold "vacuum".
 
So my question to those who realllllllyyyyyy = know -=20  is it correct that for my NA 13B I need a fuel pressure = regulator that=20 responses to manifold "Vacuum" or is the difference in description = between=20 "vacuum referenced and boost referenced " just semantics in=20 advertising?
 
Thanks
 
Ed
 
Ed Anderson
Rv-6A N494BW Rotary = Powered
Matthews,=20 NC
eanderson@carolina.rr.comhttp:/= /members.cox.net/rogersda/rotary/configs.htm#N494BW
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