Return-Path: Received: from [65.33.160.181] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WebUser 4.3c2) with HTTP id 765388 for lml@lancaironline.net; Tue, 01 Mar 2005 16:20:37 -0500 From: "Marvin Kaye" Subject: Re: [LML] Re: FADEC Rough idle explanation To: lml X-Mailer: CommuniGate Pro WebUser Interface v.4.3c2 Date: Tue, 01 Mar 2005 16:20:37 -0500 Message-ID: In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format="flowed" Content-Transfer-Encoding: 8bit Posted for "George Braly" : """ Can you please explain the math there? How do you get more HP at 5,000 with the same MP as sea level? Is that because there is less pressure at the exhaust? """ Yes. The exhaust back pressure is lower. There is a whole set of curves for this published in one of TCM's engine manuals. Generally, for the same MP and RPM, the power at 10,000 feet will be somewhat higher than it is at sea level. Purely a back pressure issue, which results in the cylinder volumetric efficiency improving slightly at altitude.