Return-Path: <13brv3@bellsouth.net> Received: from imf16aec.mail.bellsouth.net ([205.152.59.64] verified) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 374685 for flyrotary@lancaironline.net; Sun, 22 Aug 2004 22:21:05 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.64; envelope-from=13brv3@bellsouth.net Received: from rd ([65.6.194.9]) by imf16aec.mail.bellsouth.net (InterMail vM.5.01.06.08 201-253-122-130-108-20031117) with ESMTP id <20040823022034.FATX1721.imf16aec.mail.bellsouth.net@rd> for ; Sun, 22 Aug 2004 22:20:34 -0400 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Rusty's intake Date: Sun, 22 Aug 2004 21:20:57 -0500 Message-ID: <008f01c488b7$d3179fb0$6101a8c0@rd> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0090_01C4888D.EA4197B0" 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 V6.00.2800.1409 This is a multi-part message in MIME format. ------=_NextPart_000_0090_01C4888D.EA4197B0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I only remember seeing one set of pictures of your latest manifold (actually, you were showing the pictures of the crack in your intake = plenum) and I was wondering about this stuff at that time but didn't bring up = the subject of intake maniflod length. What is the diamenter of the sceet = tubing that runs from your throttle body to your plenum?=20 It's 1.75". If the tubing is not considerably larger, imagine what the intake = pulses 'see' when the TB is wide open. In other words, the motor may be functioning at WOT as if the intake tubes are VERY long which will keep = the motor from turning high RPM.=20 I do believe this is one of the current restrictions. =20 When I calculated this length (and I don't remember what temp I used) I = came up with something like 12" for 7500 rpm. I think I have the calcs at = work if anyone is interested. Ed, how about a sanity check. =20 That sounds about right. From memory, I think my intake runners are = about 15" to the end of the TB, and the sceet tubing adds about another 8-10 inches. =20 Something's going to get changed. Just don't know what yet. =20 MAP is still low, even with no inlet tubing to the TB, so I have to = conclude that the intake itself is restrictive. I can move the TB away a few = inches, and connect it to the runners via a plenum chamber, which should remove = any restriction issues in the TB. I'm already thinking of the easiest way = to do this. =20 Rusty (time to grill) =20 ------=_NextPart_000_0090_01C4888D.EA4197B0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message

I only remember seeing one set of pictures of your latest manifold = (actually,=20 you were showing the pictures of the crack in your intake plenum) and I = was=20 wondering about this stuff at that time but didn't bring up the subject = of=20 intake maniflod length. What is the diamenter of the sceet tubing that = runs from=20 your throttle body to your plenum? 

It's=20 1.75".

   If the tubing is = not=20 considerably larger, imagine what the intake pulses 'see' when the TB is = wide=20 open.  In other words, the motor may be functioning at WOT as if = the intake=20 tubes are VERY long which will keep the motor from turning  high = RPM. 

I do=20 believe this is one of the current restrictions.  =   

When I calculated this length (and I don't remember what temp I = used) I=20 came up with something like 12" for 7500 rpm.  I think I have the = calcs at=20 work if anyone is interested.  Ed, how about a sanity = check.  

That sounds=20 about right.  From memory, I think my intake runners are about = 15" to=20 the end of the TB, and the sceet tubing adds about another 8-10=20 inches.  

Something's=20 going to get changed.  Just don't know what=20 yet.  

MAP is still=20 low, even with no inlet tubing to the TB, so I have to conclude = that the=20 intake itself is restrictive.  I can move the TB away a few = inches,=20 and connect it to the runners via a plenum chamber, which should = remove any=20 restriction issues in the TB.  I'm already thinking of the easiest = way to=20 do this.  

Rusty=20 (time to grill)

 

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