X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [161.88.255.139] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WEBUSER 5.1.5) with HTTP id 1804031 for lml@lancaironline.net; Thu, 01 Feb 2007 09:22:37 -0500 From: "Marvin Kaye" Subject: Re: [LML] Re: Altitude Switch -- how's a guy to know? - take APS To: lml X-Mailer: CommuniGate Pro WebUser v5.1.5 Date: Thu, 01 Feb 2007 09:22:37 -0500 Message-ID: In-Reply-To: <019c01c74600$db709000$f710020a@nvidia.com> References: <019c01c74600$db709000$f710020a@nvidia.com> X-Priority: 3 MIME-Version: 1.0 Content-Type: text/plain;charset="iso-8859-1";format="flowed" Content-Transfer-Encoding: 8bit Posted for "colyncase on earthlink" : Rick said, High EGT's do not necessarily relate to high CHTs - and can sometimes actually be inversely related. Richer mixtures, can delay combustion timing, which can expose the EGT probe to more of the combustion heat. There is no max EGT (only a max TIT). They don't relate in an absolute way but they do tell you you are getting closer to peak. The work that George/APS did shows that there is a region surrounding peak where the cylinder internal pressure is high because peak pressure occurs nearer top dead center. You can slide that peak pressure event further after TDC by either getting richer of peak on the ROP side (extra fuel slows combustion) or leaner of peak on the LOP side (extra air slows combustion). What I didn't know before taking the APS course is just how much extra fuel it takes to get into the safe zone on the ROP side. You want to be 180 dF rich of peak if you are running 75%. That is a lot more than most pilots will give it. If you haven't taken the APS course I HIGHLY recommend it. I went in thinking I would learn the fine points of LOP operation and came out realizing how very easy it is to destroy your engine doing pretty much what we've all been taught to do. This is all backed up by hard data. ...and now you can take it on line cheap. Check out http://www.advancedpilot.com/ for only $395. Colyn -