Subject: [FlyRotary]
Re: Engine run
At about 2000 I adjusted mixture from too lean to too
rich, and nowhere does it smooth out completely
I'm with Dave on this
one. You want the smoothest MAP source possible, and that will mean
connecting all 3 ports, or perhaps just finding the one that works best.
I don’t
think I have a problem with the MAP using the average of two ports. The
reading stays quite constant for awhile, but drops when the engine falters,
then comes back up. I could try putting all three together, but then I
would not have an independent backup for controller B
At 2000 I’m seeing a 13.1 MAP reading.
Seems low to me. Is it?
I'm sure I see similar
numbers.
The only comparable data I can find from my dyno
runs was a MAP of about 17 at 1900 rpm and the engine was putting out about 30
hp. How much power does it take to run the prop at 2000 rpm?
That puts it below the stage point, yet when I
turned off the primary injectors, it continued to run; just rougher. Same
effect turning off the secondaries.
Are you surprised that it
continued to run? The EC-2 knows that you turned off a pair of injectors,
and compensates with the others as necessary. In other words, if you turn
off the primaries, below the staging point, the EC-2 will turn on the
secondaries (which were previously off). Turning off the secondaries
below the staging point shouldn't do anything, since they weren't on anyway
I guess I didn’t realize that the secondaries
would turn on below the staging point, but the thing that puzzles me is that
turning off the secondaries reduced the rpm and made it rougher. So apparently
they were on even thought the MAP reading was 13.1. Something fishy.
Fuel pressure reads 50 psi, TWM tells me it came to me
preset at 43.5. When the coolant temp read 125 when the pipes and rad
tanks were just about too hot to touch, which I guessed to be more like
140. I’m suspicious of just about every readout. Later when the WT
read 140, the CHT TC that measure temps in and out of the rads were reading
about 85. I believed backup gauges were unnecessary.
Painful as it may be,
you're going to have to verify all your EM-2 temps and pressures before you can
believe them. I mentioned before that my fuel pressure was 42, but read
59 on the latest EM-2 software. It's reading correctly now that I've done
some cal though.
A-r-r-gh!
Oh yeah; the mixture bar reads just about full scale
all the time, even when the engine is about to die from being too lean. I
have a different heated Bosch sensor, which I assumed would have the same
0-1volt range. Maybe not. Is the sensor output voltage low when
lean or rich?
This is something that
I've bugged Tracy about pretty extensively. Mine does
the same thing yours does, and Tracy says his doesn't.
I used to use the old gauge that Tracy sold, and I've done some
testing with it, and the EM-2 both connected (verified not to interfere with
each other). When the old gauge reads mid scale, the EM-2 is about 7-8
bars. Since O2 sensors are supposed to put out 0-1V, mid scale should be
.5V, so I made a variable voltage source, and used it to simulate the O2
sensor. At .5V, the EM-2 read mid scale like it's supposed to, and the
other gauge read below mid scale. From that, I concluded that the EM-2
was doing what it was designed to do, but I can't explain why my "mid
scale" mixture is well above mid scale on the EM-2. I tried
using a new sensor, of the same type others are using, and it made no
difference. Now that you have me thinking about this again, I just made a
note to "fix" this in the calibration mode.
This is interesting. I was about to
throw away my sensor, relocate the bung, and get the recommended Bosch 11027.
Don't get discouraged.
Ah-h-h; who? me! NEVER. (whinning)
All I want some simple pistons, a carburetor, and some dials with pointers.
(Ju-u-u-st kidding)
Thanks for your help,
Al