X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 14 Jun 2007 01:27:06 -0400 Message-ID: X-Original-Return-Path: Received: from global.delionsden.com ([66.150.29.112] verified) by logan.com (CommuniGate Pro SMTP 5.1.9) with ESMTPS id 2101328 for lml@lancaironline.net; Thu, 14 Jun 2007 00:41:59 -0400 Received-SPF: none receiver=logan.com; client-ip=66.150.29.112; envelope-from=n103md@yahoo.com Received: from bmackey by global.delionsden.com with local (Exim 4.62) (envelope-from ) id 1Hyh90-0002s1-Bm for lml@lancaironline.net; Thu, 14 Jun 2007 00:41:14 -0400 Received: from 69.12.132.145 ([69.12.132.145]) (SquirrelMail authenticated user bmackey) by www.bmackey.com with HTTP; Wed, 13 Jun 2007 21:41:14 -0700 (PDT) X-Original-Message-ID: <1235.69.12.132.145.1181796074.squirrel@www.bmackey.com> X-Original-Date: Wed, 13 Jun 2007 21:41:14 -0700 (PDT) Subject: [LML] Re: Boost switch From: "bob mackey" X-Original-To: lml@lancaironline.net User-Agent: SquirrelMail/1.4.8 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - global.delionsden.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [32015 2012] / [47 12] X-AntiAbuse: Sender Address Domain - yahoo.com X-Source: X-Source-Args: X-Source-Dir: > In flight today I experimented with "high" boost switch position. > It adds about 4-5 gph to the fuel flow-- and miraculously the engine > did not quit! So, for all those folks feverishly redesigning the TCM > fuel system -- relax and take a few deep breaths and have another beer. Hmmm... flipping on the boost pump causes fuel flow to increase by 4-5 gph? And *your* engine didn't quit *this time*? Good thing it was lean enough to tolerate that extra gulp of gasoline. Clearly we are all free to draw our own conclusions. My opinion is that you have just demonstrated the need for redesign. 4-5 gph is a huge increase in flow in what should be a well-regulated system. It would be intolerable in my aircraft. When I switch on my boost pump (carbureted O-320), the fuel flow changes by about 0.0 to 0.5 gph. Most of the increase seems to be transient, as if it fills the float bowl a little bit higher in the first few seconds after switching on the pump, then regulates back to the same flow. I don't see any effect on the EGT, so the cylinders apparently do not see the increase in fuel flow. OK, I'll take you up on that beer now.