Return-Path: Received: from smtpauth05.mail.atl.earthlink.net ([209.86.89.65] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 565016 for flyrotary@lancaironline.net; Mon, 13 Dec 2004 00:10:26 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.86.89.65; envelope-from=Dastaten@earthlink.net Received: from [24.238.206.157] (helo=earthlink.net) by smtpauth05.mail.atl.earthlink.net with asmtp (Exim 4.34) id 1CdiTK-00018B-KC for flyrotary@lancaironline.net; Mon, 13 Dec 2004 00:10:10 -0500 Message-ID: <41BD2412.9070004@earthlink.net> Date: Sun, 12 Dec 2004 23:09:38 -0600 From: David Staten Reply-To: Dastaten@earthlink.net User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] breaking physics news! References: In-Reply-To: Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit X-ELNK-Trace: 9a30bff84e6cb88f95c85d38d22416599ef193a6bfc3dd48bc82aa2e324f243d7cab6272b3d0f64a387f7b89c61deb1d350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 24.238.206.157

kevin lane wrote:

i came across this while looking for stainless steel tubing -

FACT! Before purchasing an oversize 2-1/2" exhaust system give it a little thought! The problem with 2-1/2" exhaust tubing (a common size mistake) is that the velocity in the system decreases with larger diameter tubing. This reduction of velocity is caused by the exhaust expanding in the larger tubing. This actually produces more back-pressure by slowing the flow. The result of this is a significant decrease in low end (2000-4500 rpm) performance of your Toyota's engine.

wow, i guess toyotas use different laws of physics :-) i thought the backpressure squared was proportional to the airflow velocity.

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The rationale given there by that blurb you pasted makes no sense whatsoever.. I wouldnt pay it any mind at all...

Dave