I used small fuel filters in the MAP sensing line.  I soldered the end closest to the intake manifold shut and then drilled a small hole through the solder.  This hole was small enough to cause instability (surging) of the engine at idle.  The hole through the solder was successively drilled larger until the surging stopped.  The resulting damping system has been in use on my plane for several years now.  I haven't tried removing it to see if the upgraded EC2's don't need this.  It's been long enough that I can't remember what size of hole I ended up with, although that would be easy enough to measure next time the cowl is off.

Steve Boese


________________________________________
From: Rotary motors in aircraft [flyrotary@lancaironline.net] On Behalf Of Bill Bradburry [bbradburry@bellsouth.net]
Sent: Monday, March 29, 2010 9:37 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: FLIGHT DATA 1

I have heard of others using some kind of expansion chamber like this, but
Don is the first I have heard of including a restriction in the line as
well.  He got an improvement with the restriction before he added the
expansion chamber.  I wonder if both would be needed to dampen out the
pulses?

Bill B