X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao106.cox.net ([68.230.241.40] verified) by logan.com (CommuniGate Pro SMTP 5.2.8) with ESMTP id 3182352 for flyrotary@lancaironline.net; Mon, 22 Sep 2008 11:56:40 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.40; envelope-from=alventures@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao106.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20080922155602.FRTC8615.fed1rmmtao106.cox.net@fed1rmimpo02.cox.net> for ; Mon, 22 Sep 2008 11:56:02 -0400 Received: from BigAl ([72.192.137.74]) by fed1rmimpo02.cox.net with bizsmtp id Hrw31a0011cVYgg04rw355; Mon, 22 Sep 2008 11:56:03 -0400 X-Authority-Analysis: v=1.0 c=1 a=VXQ9fFqNYwlw3z6S3jEA:9 a=MIeBrXD8wNpb4l3ArI3HWU1iohgA:4 a=vNGxQsTWjH8A:10 a=7y33EPt8ZvTGXCNY-00A:9 a=N4V76wWWvUUjR2V1ljYA:7 a=0Gqt1F601JnfzE7hDaQvKrSbmwAA:4 a=37WNUvjkh6kA:10 X-CM-Score: 0.00 From: "Al Gietzen" To: "Rotary motors in aircraft" Subject: Manifold vacuum gage Date: Mon, 22 Sep 2008 08:56:41 -0800 Message-ID: <13509DAC3986421BB61489DA61083D9F@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0006_01C91C91.21CCDF00" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0006_01C91C91.21CCDF00 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Mark, I was thinking along the lines of the restrictors in the vacuum = lines I seen in the pile of tubing from a couple old cars that I scraped, or = maybe a 1/8" piece of steel tubing with a drop of solder in and a hole drilled thru the solder. The aquarium valve would sure be a simple way to make = a restrictor. JohnD =20 John; =20 That's essentially what I did, except I used epoxy instead of solder, = and used a .050 wire to form the orifice. Then used a fuel filter as an accumulator. It improved the idle of the engine. =20 =20 I had also found that using the un-damped MAP signal for the pressure-referenced fuel pressure regulator caused rapid pulsations in = the fuel pressure. I don't know that this affected engine operation in any = way, but decided it could an unknown stressing factor on the fuel system. = Using the damped MAP signal eliminated that phenomenon. =20 All of this is influenced by the location of the MAP measuring ports. = Mine is picked up relatively close to the ports (about 6") and would likely = have stronger pulse than if picked up in an air box at the far end of long runners.=20 =20 Al G. ------=_NextPart_000_0006_01C91C91.21CCDF00 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Mark, I was thinking along the lines of the = restrictors in the vacuum lines I seen in the pile of tubing from a couple old cars = that I scraped, or maybe a 1/8" piece of steel tubing with a drop of = solder in and a hole drilled thru the solder. The aquarium valve would sure = be a simple way to make a restrictor. JohnD

John;

That’s essentially what I did, except I used = epoxy instead of solder, and used a .050 wire to form the orifice. Then used a = fuel filter as an accumulator. It improved the idle of the = engine.

I had also found that using the un-damped MAP = signal for the pressure-referenced fuel pressure regulator caused rapid pulsations = in the fuel pressure. I don’t know that this affected engine = operation in any way, but decided it could an unknown stressing factor on the fuel system. Using the damped MAP signal eliminated that = phenomenon.

All of this is influenced by the location of the = MAP measuring ports. Mine is picked up relatively close to the ports = (about 6”) and would likely have stronger pulse than if picked up in an air box at = the far end of long runners.

Al G.

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