From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] Re: Altitude Switch -- how's a guy to know?
To: lml
Date: Thu, 01 Feb 2007 09:21:08 -0500
Message-ID: <web-1804013@logan.com>
In-Reply-To: <00b701c745cf$52d0f040$0500a8c0@mountain0676a7>
References: <00b701c745cf$52d0f040$0500a8c0@mountain0676a7>
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Posted for "Bryan Burr" <bjburr@mwheli.com>:

  Usually at the point that I pass 10000' I am planning a continued climb
  to something higher.  Therefore I am at full rich.  In the summer to
  maintain cyl temp cooling I keep the airspeed over 140.  If I turn on
  the low boost over 10000' the egt's climb about 30 degrees (still
  acceptably cool) and the cht's (1&2) will climb over 400 degrees
  (unacceptable to me).  If I keep the boost pump off I can keep the cht's
  in check.  Once established in cruise I can reduce rpm, mp, and mixture
  and turn on LOW BOOST and keep all the temps managed.
  
  My question still is why does the LOW BOOST create a reduction in fuel
  flow which in turn results in climbing EGT and CHT?  It would seem
  logical that the fuel boost pump is causing a restriction (although it
  is providing an additional pressure source to the engine driven fuel
  pump)that results in a leaning effect.
  
  Bryan
  N132BB