X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 06 Aug 2005 01:30:18 -0400 Message-ID: X-Original-Return-Path: Received: from imo-m18.mx.aol.com ([64.12.138.208] verified) by logan.com (CommuniGate Pro SMTP 4.3.6) with ESMTP id 626300 for lml@lancaironline.net; Fri, 05 Aug 2005 18:08:49 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.208; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m18.mx.aol.com (mail_out_v38_r4.1.) id q.1c6.2e0159fa (4320) for ; Fri, 5 Aug 2005 18:08:01 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <1c6.2e0159fa.30253d41@aol.com> X-Original-Date: Fri, 5 Aug 2005 18:08:01 EDT Subject: Re: [LML] Re: Lower Cowl Air Temperature - Induction Air - Heater Air Temp X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1123279681" X-Mailer: 9.0 Security Edition for Windows sub 5009 X-Spam-Flag: NO -------------------------------1123279681 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 8/5/2005 8:50:25 A.M. Central Standard Time, walter@advancedpilot.com writes: As an example, in my Twin Beech, when the OAT is 92dF, the temperature AFTER the venturi in the carburetor is 35dF. That temperature drop across the venturi is not there in an injected engine. Now add another 100dF so that the IAT is 192 and the carb temp is 135. That is not a good thing. At high powers, with higher CHTs, the detonation margin is quite a bit narrower. This isn't too much of a problem in the lower compression engines but can quickly cross the threshold in the higher compression engines. If you draw a higher (by 100dF) IAT when the OAT is very cold, it's not a big deal--the engine just thinks it's summer time! If you do that during the summer, when the OAT is already high, it could quickly become an issue in the higher compression engines. By the time one adds 9 or 10:1 pistons, it can get ugly quickly. This effect is why we think intercoolers are so important. Walter, OK, I will continue to suck unfiltered air as long as it is only diesel-greasy Chicago air - I would have to do something else if I was in windy-gritty West Texas. Bugs I burn as pure protein. Inter-coolers, for me, just introduce more cooling drag. Of course, if the cooled induction air power pick-up cubed the drag loss, I might reconsider. Also, the inter-cooler would have to be inconviently introduced before the throttle body - otherwise, the fuel computer would be confused. Have you measured the cooling effect of atomization at the cylinder head? If not, why would it be different than that occurring in the carb? Hmmmm.... every answer gives rise to more questions. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) -------------------------------1123279681 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 8/5/2005 8:50:25 A.M. Central Standard Time,=20 walter@advancedpilot.com writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>As an=20 example, in my Twin Beech, when the OAT is 92dF, the temperature
AFTER= the=20 venturi in the carburetor is 35dF.  That temperature drop
across=20= the=20 venturi is not there in an injected engine.  Now add another
100d= F so=20 that the IAT is 192 and the carb temp is 135.  That is not a
good= =20 thing.  At high powers, with higher CHTs, the detonation margin is=20
quite a bit narrower.  This isn't too much of a problem in the lo= wer=20
compression engines but can quickly cross the threshold in the higher=20
compression engines.

If you draw a higher (by 100dF) IAT when t= he=20 OAT is very cold, it's not
a big deal--the engine just thinks it's sum= mer=20 time!  If you do that
during the summer, when the OAT is already=20 high, it could quickly
become an issue in the higher compression=20 engines.  By the time one
adds 9 or 10:1 pistons, it can get ugly= =20 quickly.

This effect is why we think intercoolers are so=20 important.
Walter,
 
OK, I will continue to suck unfiltered air as long as it is=20 only diesel-greasy Chicago air - I would have to do something else = ;if=20 I was in windy-gritty West Texas.  Bugs I burn as pure protein.
 
Inter-coolers, for me, just introduce more cooling drag.  Of cours= e,=20 if the cooled induction air power pick-up cubed the drag loss, I might=20 reconsider.  Also, the inter-cooler would have to be=20 inconviently introduced before the throttle body - otherwise, the fuel=20 computer would be confused.
 
Have you measured the cooling effect of atomization at the cylinder=20 head?  If not, why would it be different than that occurring in the=20 carb?
 
Hmmmm.... every answer gives rise to more questions.=20
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)



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