X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from poplet2.per.eftel.com ([203.24.100.45] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with ESMTP id 4194892 for flyrotary@lancaironline.net; Sun, 04 Apr 2010 02:20:58 -0400 Received-SPF: none receiver=logan.com; client-ip=203.24.100.45; envelope-from=lendich@aanet.com.au Received: from sv1-1.aanet.com.au (mail.aanet.com.au [203.24.100.34]) by poplet2.per.eftel.com (Postfix) with ESMTP id E40871737CE for ; Sun, 4 Apr 2010 14:20:22 +0800 (WST) Received: from ownerf1fc517b8 (203.171.92.134.static.rev.aanet.com.au [203.171.92.134]) by sv1-1.aanet.com.au (Postfix) with SMTP id 68863BEC017 for ; Sun, 4 Apr 2010 14:20:21 +0800 (WST) Message-ID: From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Weber chokes Date: Sun, 4 Apr 2010 16:20:22 +1000 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Antivirus: avast! (VPS 100403-1, 04/03/2010), Outbound message X-Antivirus-Status: Clean Bill, On researching the Weber carb it seems it was originally developed to provide different chokes, one for low rpm and one for high rpm. That would be good if we had siamesed PP with different sized runners - sounds complicated. George ( down under) > George, > You are correct but remember the manifold efficiency is based on having > the correct size runners to begin with. The venturi is needed to improve > vacuum to draw fuel. The Weber has a secondary venturi as well, the little > bullseye one in the middle. So things are complicated in any case. A well > tuned FI is almost always better. > Bill Jepson > ------Original Message------ > From: George Lendich > Sender: Rotary motors in aircraft > To: Rotary motors in aircraft > ReplyTo: Rotary motors in aircraft > Subject: [FlyRotary] Re: Weber chokes > Sent: Apr 3, 2010 2:31 PM > > Lynn or Bill, > Having a quick look at the web sites, I see the choke does restrict flow > and > increase venturi effect, which is good for sucking up fuel from the float > bowl. However without maintaining that restricted size, through to the > combustion chamber, the flow returns to a slower flow. So I don't see a > benefit for increased VE without the smaller sized manifold inlet tube ( > matching the choke size) OR a reducing diameter manifold inlet tube (a > style > Lynn mentioned in an earlier post). > Or am I wrong? > George ( down under) > >> Lynn, >> It is worth mention that on many Webers the "choke" is changeable on >> size. >> Also many people don't understand thar choke means primary venturi, not a >> starting restriction used on many big 4 barrel. carbs. I know this is >> second nature to us, we grew up on this stuff. Many of our younger >> contributors have never even worked on a carburetor. I used two 42 dcoe >> Webers on motorcycle engines used om sports racers. We ran 38-42mm >> venturis. >> Bill Jepson >> Sent from my Verizon Wireless BlackBerry >> >> -----Original Message----- >> From: Lynn Hanover >> Date: Sat, 3 Apr 2010 08:59:29 >> To: Rotary motors in aircraft >> Subject: [FlyRotary] Weber chokes >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: >> http://mail.lancaironline.net:81/lists/flyrotary/List.html >> >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: >> http://mail.lancaironline.net:81/lists/flyrotary/List.html >> > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > Sent from my Verizon Wireless BlackBerry > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html >