I agree that being able to view the
contents of the mixture correction table is very helpful. In addition to
logging over 20 parameters sent by the EC2, the program that I have on my IPAQ
allows me to see the entire table in real time and the changes made to it while
performing the tuning process. It also allows me to save the table and
edit it independently of the EC2 and load it back into the EC2. Any
number of these tables can be saved in the IPAQ and reviewed, edited, and/or
reloaded as desired. A poor quality image of an IPAQ screen showing a mixture
correction table is attached. I guess this is a shameless plug to look
into getting Ed’s EFISM or Tracy’s EM3.
Steve
-----Original Message-----
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Mike Wills
Sent: Thursday, April 23, 2009
11:43 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: EC2
address range issue
My EC2 tuning experience has been
similar to yours. I found that mine did not seem to work as Tracy describes in
the EC2 manual. Initially my engine never ran in the region where the MCT is
RPM driven. My MCT pointer was always MAP driven. I beleive at least in my case
that a variety of small issues combined led to this behavior. As i have
continued to tweak and refine my installation I find that it operates more like
intended.
Initially all of my tuning was done
based on RPM, MAP, O2, and EGTs. When I designed and built my instrument
panel Tracy's EM didnt exist so I dont have one. Tuning it as I did
resulted in acceptable engine performance, but I knew it could be better. I
installed one of Ed Anderson's EFISM so I could get a look at what was loaded
in the MCT. Even though the engine was running OK, I found many instances
of large transitions between adjacent locations in the table. Using the
EFISM I tweaked the MCT and smoothed all of these transitions. After this I
found that the engine would idle more smoothly and at lower RPMs and I was now
running in the region where RPM drives the MCT.
Another thing I found was
the EC2 seems to be sensitive to location of the MAP vacuum sources
in the intake manifold. My intake uses an essentially stock Mazda lower
casting. There are existing vacuum ports in this casting that I used to plumb
the MAP sensors. In my early debugging efforts Tracy suggested moving these
taps out toward the plenum. I tried this but there was no noticeable difference
so I changed it back.
At the advice of a number of users I
added some small reservoirs, essentially a vacuum capacitor, to smooth the MAP
inputs. This did result in a slight improvement in performance.
After all of the MCT tweaking using
the EFISM I decided to once again try tapping vacuum at the plenum. This time I
did notice a difference with a further improvement at idle settings (smoother
and lower RPM). I believe the less than ideal MCT tune that I started with was
masking the effect of an improved vacuum source. After the tuning and the
relocation of vacuum taps out to the plenum I was able to eliminate the vacuum
reservoirs.
All of this minor tweaking has
resulted in major improvements in engine performance. In my case I dont think
it would have been possible to tweak the engine to this state of tune without
the EFISM (or an EM). I think some sort of tuning aid that provides a visual
reference of what the MCT looks like and what MCT value is being used at any
given time is essential. Being able to snag the data and review it after the
fact like Steve has done would also be incredibly useful.