X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m16.mx.aol.com ([64.12.138.206] verified) by logan.com (CommuniGate Pro SMTP 5.0.4) with ESMTP id 887184 for flyrotary@lancaironline.net; Sun, 18 Dec 2005 12:27:16 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.206; envelope-from=WRJJRS@aol.com Received: from WRJJRS@aol.com by imo-m16.mx.aol.com (mail_out_v38_r6.3.) id q.2c7.6d23b7 (4468) for ; Sun, 18 Dec 2005 12:26:29 -0500 (EST) From: WRJJRS@aol.com Message-ID: <2c7.6d23b7.30d6f5c5@aol.com> Date: Sun, 18 Dec 2005 12:26:29 EST Subject: Re: [FlyRotary] Exhaust tuning To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1134926789" X-Mailer: 9.0 for Windows sub 5044 X-Spam-Flag: NO -------------------------------1134926789 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 12/17/2005 6:58:55 PM Pacific Standard Time, montyr2157@alltel.net writes: Two cycle recips can use a divergent/convergent cone type expansion chamber. The timing of the pulses alternately draws gases out of the combustion chamber to assist scavenging to the point of overscavenging at the operating point, and then "stuffs" the overscavenged mixture back in at the last moment as the port closes to effectively supercharge the engine Monty, The rotary is similar to 2-cycles only in that it has a port rather than a valve in the exhaust. I have seen Mazda factory race exhaust systems from the unmuffled racing era. They use a "continous divergence system" The pipe is tapered slightly from the port all the way to the exit. (expanding) Several later tuned systems use extraction principles just like a common piston four-cycle. A solid pipe of a length tuned to your most common RPM is the most important part of the system. After the first 20" you can use different collection methods as long as the restriction is minimal. Bill Jepson -------------------------------1134926789 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 12/17/2005 6:58:55 PM Pacific Standard Time, montyr2= 157@alltel.net writes:
Two cycle recips can use a divergent/= convergent cone type expansion chamber. The timing of the pulses alternately= draws gases out of the combustion chamber to assist scavenging to the point= of overscavenging at the operating point, and then "stuffs" the oversc= avenged mixture back in at the last moment as the port closes to effect= ively supercharge the engine
Monty,
The rotary is similar to 2-cycles only in that it has a port rather tha= n a valve in the exhaust. I have seen Mazda factory race exhaust systems fro= m the unmuffled racing era. They use a "continous divergence system" The pip= e is tapered slightly from the port all the way to the exit. (expanding) Sev= eral later tuned systems use extraction principles just like a common piston= four-cycle. A solid pipe of a length tuned to your most common RPM is the m= ost important part of the system. After the first 20" you can use different=20= collection methods as long as the restriction is minimal.
Bill Jepson
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