Hi Mike,
Interesting reaction of engine to your DNA
muffler. A possible explanation for richer across the board. It
appears that the DNA muffler may offer less back pressure to the engine meaning
you get more air into the engine at any given rpm. That could increase
your manifold pressure and drive the EC2 to enrichen the mixture to
compensate. The reason the top end rpm may not change is that at that
point there is some other restriction such as the intake, TB, etc that may come
into play. Just a theory of course.
Ed
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Mike Wills
Sent: Saturday, September 05, 2009
11:47 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] DNA muffler
Received my DNA muffler this past week and got it installed
and running. Havent flown it yet, but have done some taxi and full power
runups. So far I'm a little disappointed. It doesnt appear to be any quieter
than my home made muffler. I'll reserve judgement until I actually fly it, but
from the cockpit the noise level seems the same, and my buddy standing about 50
' away said he thought the noise level was the same.
One thing not the same - the muffler screwed up my
tuning. It appears to be considerably richer now all across the RPM range. And
the big bog at the staging point that took me so long to tune out is back with
a vengeance. Oddly, in spite of the tune issues it still appears to reach the
same static RPM as previously.
Looks like the solution for me is going to be the high
$ headset and the rest of the world is just going to have to live with it.
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