Return-Path: Sender: (Marvin Kaye) To: lml Date: Sun, 13 Apr 2003 17:21:25 -0400 Message-ID: X-Original-Return-Path: Received: from [65.66.11.38] (HELO qbert.gami.com) by logan.com (CommuniGate Pro SMTP 4.1b3) with ESMTP id 2121103 for lml@lancaironline.net; Sun, 13 Apr 2003 13:59:38 -0400 Received: by QBERT with Internet Mail Service (5.5.2650.21) id ; Sun, 13 Apr 2003 13:08:30 -0500 X-Original-Message-ID: <52548863F8A5D411B530005004759A93391F3F@QBERT> From: George Braly X-Original-To: 'Lancair Mailing List' Subject: RE: [LML] Re: Tuned Exhaust System for Legacy answers X-Original-Date: Sun, 13 Apr 2003 13:08:29 -0500 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C301E7.B03CA646" This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ------_=_NextPart_001_01C301E7.B03CA646 Content-Type: text/plain; charset="iso-8859-1" I have actually done some very careful dyno testing (the before-after-before type of comparisons - - - all in the same day) of a variety of different tuned exhaust configurations on aircraft piston engines. If you are expecting 5% - - then think 2-3% - - and at WHAT RPM ? 2700? OK... but if you do that, then think MINUS (-) 2% at some other RPM - - like 2400 RPM when you are in cruise. No free lunch. In general, tuned exhausts are going to be heavier, more complicated, and harder to maintain. They are not going to effect the CHTs in any way you are going to be able to reliably measure. Regards, George PS. It is very easy to fail to hold the relevant variables - - constant. Such as failing to hold the F/A ratio constant when enjoying the small improvement in volumetric efficiency at some particular RPM. -----Original Message----- From: CHBAviation@aol.com [mailto:CHBAviation@aol.com] Sent: Saturday, April 12, 2003 4:50 PM To: Lancair Mailing List Subject: [LML] Re: Tuned Exhaust System for Legacy answers Thanks for inquiring. Gains hoping to see are 5%-15% gain in HP and torque. However, I don't think we'll see the 15%. Aircraft engines don't turn fast enough to give us the 15%. We should see a cooler CHT temperatures since the scavenging will be improved. I've just returned from Sun 'N Fun and hope to get the system dynode. I will be dynode testing this new system as well as Lancair's current system. Chuck Brenner CHB Aviation LLC Go Fast Parts 303-261-4466 chbaviation@aol.com ------_=_NextPart_001_01C301E7.B03CA646 Content-Type: text/html; charset="iso-8859-1"

I have actually done some very careful dyno testing (the before-after-before type of comparisons - - - all in the same day) of a variety of different tuned exhaust configurations on aircraft piston engines.

If you are expecting 5% - - then think 2-3% - - and at WHAT RPM ? 2700? OK... but if you do that, then think MINUS (-) 2% at some other RPM - - like 2400 RPM when you are in cruise. No free lunch.

In general, tuned exhausts are going to be heavier, more complicated, and harder to maintain.

They are not going to effect the CHTs in any way you are going to be able to reliably measure.

Regards, George

PS. It is very easy to fail to hold the relevant variables - - constant. Such as failing to hold the F/A ratio constant when enjoying the small improvement in volumetric efficiency at some particular RPM.

-----Original Message-----
From: CHBAviation@aol.com [mailto:CHBAviation@aol.com]
Sent: Saturday, April 12, 2003 4:50 PM
To: Lancair Mailing List
Subject: [LML] Re: Tuned Exhaust System for Legacy answers

Thanks for inquiring.

Gains hoping to see are 5%-15% gain in HP and torque. However, I don't think we'll see the 15%. Aircraft engines don't turn fast enough to give us the 15%. We should see a cooler CHT temperatures since the scavenging will be improved. I've just returned from Sun 'N Fun and hope to get the system dynode. I will be dynode testing this new system as well as Lancair's current system.

Chuck Brenner
CHB Aviation LLC
Go Fast Parts
303-261-4466
chbaviation@aol.com

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