X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao01.cox.net ([68.230.241.38] verified) by logan.com (CommuniGate Pro SMTP 4.3c5) with ESMTP id 949408 for flyrotary@lancaironline.net; Wed, 18 May 2005 21:36:05 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.38; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao01.cox.net (InterMail vM.6.01.04.00 201-2131-118-20041027) with ESMTP id <20050519013518.OQSA7629.fed1rmmtao01.cox.net@BigAl> for ; Wed, 18 May 2005 21:35:18 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] More MAP measurement questions Date: Wed, 18 May 2005 18:35:34 -0700 Message-ID: <000001c55c13$0d91a530$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C55BD8.6132CD30" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 This is a multi-part message in MIME format. ------=_NextPart_000_0001_01C55BD8.6132CD30 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable =20 Greetings, =20 I'm working on a new theory about my low MAP reading. The theory is = that this isn't a problem at all, but rather a difference in the way it's = being measured. =20 =20 What's new about this theory? This is what I was telling you a week or = two ago. :-) I apologize for lack of clarity, causing you to have to re-invent this theory. =20 Al (Also running TWM TB) =20 The TWM TB has a MAP port about 4 inches past the entrance of the TB = throat. That means I'm measuring the air pressure on the suction side of the = largest restriction in the system (from wide open space, to 41mm tube). Since there's no significant restriction downstream from the TB, I would guess that I could measure the MAP at the inlet of the side housing, and = wouldn't find it significantly lower than what I'm seeing in the TWM TB. In = other words, I'm measuring the worst possible MAP, which is the suction side. = =20 =20 From what I understand, the typical (if there is such a thing) intake = has a large TB, feeding into an open plenum, then into the smaller runners = that go to the engine. If I'm not mistaken, virtually everyone is measuring = their MAP in the open plenum, before the air has to enter the smaller runners = to go to the engine. In other words, the people who are reading 30" are = doing it on the pressure side of the largest restriction. =20 =20 I could babble on about this, but my point is to ask where others are measuring their MAP (turbo folks need not apply). You'll also have to = give a general description of your intake layout. I already know that Ed = and Tracy are using the "typical" situation. Is anyone measuring MAP in the runner to the engine? =20 =20 Cheers, Rusty (duty calls...) =20 ------=_NextPart_000_0001_01C55BD8.6132CD30 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

 

Greetings,

=

 

I'm working on a new theory = about my low MAP reading.  The theory is that this isn't a problem at all, = but rather a difference in the way it's being measured.  =

 

What’s new about this theory?  This is what I was telling you a week or two ago. = J

I apologize for lack of clarity, = causing you to have to re-invent this theory.

 

Al (Also running TWM = TB)

 

The TWM TB has a MAP port = about 4 inches past the entrance of the TB throat.   That means I'm = measuring the air pressure on the suction side of the largest restriction in the = system (from wide open space, to 41mm tube).   Since there's no = significant restriction downstream from the TB, I would guess that I could = measure the MAP at the inlet of the side housing, and wouldn't find it = significantly lower than what I'm seeing in the TWM TB.  In other words, I'm measuring the worst possible MAP, which is the suction side.    

 

From what I understand, the = typical (if there is such a thing) intake has a large TB, feeding into an open = plenum, then into the smaller runners that go to the engine.  If I'm not mistaken, virtually everyone is = measuring their MAP in the open plenum, before the air has to enter the smaller = runners to go to the engine.  In other words, the people who = are reading 30" are doing it on the pressure side of the largest restriction.  

 

I could babble on about = this, but my point is to ask where others are measuring their MAP (turbo folks need = not apply).  You'll also have to give a general description of your = intake layout.   I already know that Ed and Tracy are using the "typical" situation.  Is anyone measuring MAP in the = runner to the engine?  

 

Cheers,

Rusty (duty = calls...)

 

------=_NextPart_000_0001_01C55BD8.6132CD30--