X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 50 [XX] (100%) SPAM DICTIONARY WORDS: low count Return-Path: Received: from imo-m23.mx.aol.com ([64.12.137.4] verified) by logan.com (CommuniGate Pro SMTP 5.1.8) with ESMTP id 2042039 for flyrotary@lancaironline.net; Sun, 13 May 2007 10:54:03 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.4; envelope-from=Lehanover@aol.com Received: from Lehanover@aol.com by imo-m23.mx.aol.com (mail_out_v38_r9.2.) id q.d12.a8e55ba (42805) for ; Sun, 13 May 2007 10:53:15 -0400 (EDT) From: Lehanover@aol.com Message-ID: Date: Sun, 13 May 2007 10:53:15 EDT Subject: Re: [FlyRotary] Exhaust insert To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1179067995" X-Mailer: 9.0 Security Edition for Windows sub 5366 X-Spam-Flag: NO -------------------------------1179067995 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 5/13/2007 8:31:02 A.M. Eastern Daylight Time, jskmberki@alltel.net writes: What type of material is the insert for the exhaust port found in the 2nd gen motors made from? Is it removable? How could one enlarge the exhaust port? Do you just use a turbo housing? Thanks Joe Berki I don't know what it is, but it is harder than Chinese arithmetic. The liner allows for high exhaust gas temps without additional cooling. There is a thermal break between the liner and the aluminum housing. The 13B liners are much thicker than the 12A liners. When the liner is removed the outer end of the port becomes much too big. So in the 12A engines a replacement for the outer ring in aluminum is pressed in to replace the biggest part of the liner, sort of a thick ring at the outer port face. Even when the 13B exhaust port is reshaped for racing, the liner is left in place. The port timing is controlled by the shape of the opening into the housing face of the port, and even extreme timing can be done without removing the liner. Exhaust headers with 2" or just a bit smaller IDs are preferred. Exhaust gasses leave the housing supersonic, and at very low pressure. Great car should be taken to make the path flawlessly smooth for best performance. The turbo housings have a smooth liner, as the hot side of the turbo will help silence the engine and adequate muffler design and complexity is much reduced. The nonturbo housings have a wedge shaped half tube on the floor of the liner that breaks the flow into two paths and segments the shock wave, reducing its mass slightly and reducing the need for extra muffling. Wherever the exhaust flow slows to subsonic, there is the sonic boom from years ago. That must be managed inside of a very rigid muffler lest it drive you crazy, and disassemble the strongest muffler. So the nonturbo housings are better from the noise standpoint. The loss of HP from the insert is very minor. Lynn E. Hanover ************************************** See what's free at http://www.aol.com. -------------------------------1179067995 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 5/13/2007 8:31:02 A.M. Eastern Daylight Time,=20 jskmberki@alltel.net writes:

<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>

What type of material is the insert for t= he=20 exhaust port found in the 2nd gen motors made from? Is it=20 removable? How could one enlarge the exhaust port? Do you just= use=20 a turbo housing? Thanks

Joe Berki

I don't know what it is, but it is harder than Chinese arithmetic. The=20 liner allows for high exhaust gas temps without additional cooling. There is= a=20 thermal break between the liner and the aluminum housing. The 13B liners are= =20 much thicker than the 12A liners. When the liner is removed the outer=20= end=20 of the port becomes much too big. So in the 12A engines a

replacement for the outer ring in aluminum is pressed in to replace the= =20 biggest part of the liner, sort of a thick ring at the outer port face.

Even when the 13B exhaust port is reshaped for racing, the liner is lef= t in=20 place. The port timing is controlled by the shape of the opening into t= he=20 housing face of the port, and even extreme timing can be done without removi= ng=20 the liner.

Exhaust headers with 2" or just a bit smaller IDs are preferred. Exhaus= t=20 gasses leave the housing supersonic, and at very low pressure. Great car sho= uld=20 be taken to make the path flawlessly smooth for best performance.

The turbo housings have a smooth liner, as the hot side of the turbo wi= ll=20 help silence the engine and adequate muffler design and complexity is much=20 reduced. The nonturbo housings have a wedge shaped half tube on the fl= oor=20 of the liner that breaks the flow into two paths and segments the shock wave= ,=20 reducing its mass slightly and reducing the need for extra muffling. Whereve= r=20 the exhaust flow slows to subsonic, there is the sonic boom from years ago.=20= That=20 must be managed inside of a very rigid muffler lest it drive you crazy, and=20 disassemble the strongest muffler.

So the nonturbo housings are better from the noise standpoint. The loss= of=20 HP from the insert is very minor.

Lynn E. Hanover

See w= hat's free at AOL.= com.

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