Return-Path: Received: from pop3.olsusa.com ([63.150.212.2] verified) by logan.com (CommuniGate Pro SMTP 3.4.5) with ESMTP id 772502 for rob@logan.com; Wed, 02 May 2001 14:50:17 -0400 Received: from mail.advanstars.com ([209.117.152.195]) by pop3.olsusa.com (Post.Office MTA v3.5.3 release 223 ID# 0-71175U5500L550S0V35) with ESMTP id com for ; Wed, 2 May 2001 14:28:03 -0400 Received: from progress.com ([192.233.92.200]) by mail.advanstars.com (Netscape Messaging Server 4.15) with ESMTP id GCQ0YD01.0X2; Wed, 2 May 2001 14:35:01 -0400 Message-ID: <3AF0521A.307A6F23@progress.com> Date: Wed, 02 May 2001 14:29:46 -0400 From: Marcelo Pacheco Organization: PROGRESS Software Professional Services MIME-Version: 1.0 To: Lancair list CC: George Braly Subject: Re: Running lean of peak Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailing-List: lancair.list@olsusa.com Reply-To: lancair.list@olsusa.com <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Oh boy I'm so glad we finally started a inteligent, fact finding conversation about LOP, instead of just hitting on Old Wife's Tail again and again. Dan Schaefer's -235 engine, you probably don't have good fuel distribution or you're having spark timing issues. Before you can run LOP agressively, you need an engine that is getting very similar fuel-air mixtures on all cylinders. Most engines don't go nearly close enough. Pretty much any non fuel injected engine won't have good fuel-air mixture distribution. I have the same issues on the Skyhawk's O-320's I use to fly until my lancair gets of the ground. Jim Scales TCM IO 550G, as long as you're high enough that you don't have enough MP available to exceed 65% power, you can lean your engine as you'd like, to get the best performance. You have too little air in the engine to cause detonation anyhow. In your case, I would run the engine just barely lean of peak to get as close as possible to 100% fuel and air consumption. This will give the best fuel consumption with very little power loss. If you're low enough that you still have over 23" of power available, run full MP and lean to a fuel flow that will give you the desired power output, LOP. George, one issue brought a few days ago was that the excess lead (from excess fuel operating ROP) actually helps lubricate the exaust valves. Another theory was thrown that excess hot oxygen from an agressive LOP combustion would help oxydize things in the engine while a ROP mixture having consumed all oxygen wouldn't suffer from this. I don't believe that's true, but have no technical data to counteract that, except that because an agressively LOP mixture runs way cooler, that should reduce any kind of oxydation issues on exaust valves and other components. Marcelo Pacheco PP-ASEL IFR >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://www.olsusa.com/Users/Mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>