X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-mb02.mx.aol.com ([64.12.207.163] verified) by logan.com (CommuniGate Pro SMTP 5.3.10) with ESMTP id 4586370 for flyrotary@lancaironline.net; Sat, 20 Nov 2010 11:40:31 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.207.163; envelope-from=Lehanover@aol.com Received: from imo-da01.mx.aol.com (imo-da01.mx.aol.com [205.188.169.199]) by imr-mb02.mx.aol.com (8.14.1/8.14.1) with ESMTP id oAKGdt9E003287 for ; Sat, 20 Nov 2010 11:39:55 -0500 Received: from Lehanover@aol.com by imo-da01.mx.aol.com (mail_out_v42.9.) id q.ccd.7b50adc9 (37577) for ; Sat, 20 Nov 2010 11:39:45 -0500 (EST) Received: from magic-d17.mail.aol.com (magic-d17.mail.aol.com [172.19.155.133]) by cia-mb05.mx.aol.com (v129.7) with ESMTP id MAILCIAMB052-92c94ce7f9d11f6; Sat, 20 Nov 2010 11:39:45 -0500 From: Lehanover@aol.com Message-ID: <26330.6be4a566.3a1953d1@aol.com> Date: Sat, 20 Nov 2010 11:39:45 EST Subject: Re: [FlyRotary] Re: Tangential Muffler To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_26330.6be4a566.3a1953d1_boundary" X-Mailer: 9.0 Security Edition for Windows sub 5382 X-AOL-IP: 72.187.199.116 X-Spam-Flag:NO X-AOL-SENDER: Lehanover@aol.com --part1_26330.6be4a566.3a1953d1_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 11/20/2010 9:36:13 A.M. Eastern Standard Time, msteitle@gmail.com writes: Lynn, Interesting point. I had never really considered that aspect of exhaust design. What ID tube works best for a p-port? Mark I used what the engine builder (Darryl Drummond) started us out on. That was 1 7/8" ID for the bridge ported 12-A. Same for the Periphery ported 12-A. Good up to 10,000 RPM. Probably fine for a 13-B at 6,500 RPM. In no case would I go over 2" ID. The scavenging effect comes from a high velocity slug moving away from the port. The larger the diameter of the tube the lower that velocity. Measure the port opening and use that as the inside diameter. You can go a bit larger, but not smaller. Once collected you can go larger to exit to: Maybe even that homogenizing muffler. Lynn E. Hanover --part1_26330.6be4a566.3a1953d1_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 11/20/2010 9:36:13 A.M. Eastern Standard Time,=20 msteitle@gmail.com writes:

Lynn, =20

Interesting point. I had never really considered that aspect= of=20 exhaust design.

What ID tube works best for a p-port?

Mark

I used what the engine builder (Darryl Drummond) started us out on.= That=20 was 1 7/8" ID for the bridge ported 12-A. Same for the Periphery ported 12= -A.=20 Good up to 10,000 RPM. Probably fine for a 13-B at 6,500 RPM. In no case= would I=20 go over 2" ID. The scavenging effect comes from a high velocity slug movin= g away=20 from the port. The larger the diameter of the tube the lower that velocity= .=20 Measure the port opening and use that as the inside diameter. You can go= a bit=20 larger, but not smaller.

Once collected you can go larger to exit to: Maybe even that homogeni= zing=20 muffler.

Lynn E. Hanover

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