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Hi Don,
The manifold pulses are from the variations in pressure due to the intake cycle, I found that adding a little extra length was all I needed for the moderate benefit.
I just recently discovered that when I originally did my timing, I really messed up because it seems I was running almost 40 degrees of advance. In conjunction with excessive coolant temps at the time, it is no wonder I was having problems with detonation. Now that I have moved the advance back to around 20 degrees, and never get any temps above about 170, I never come across detonation anymore (duh!). I now run up to 40" MAP for take off and usually cruise at 30". That also solved the last of my rough running at idle issues. I can now idle down below 600 rpm without missing if I want, but keep it above 1200 to avoid the gear box rattle.
Regarding blow by... There should be minimal. I run my vent line down my gear leg because I do get a few drops of oil out there. But if you are getting a lot you may have a problem.. The detonation issues I was having tended to break my side seals. When that occured, I would get excessive blow by - manifest by excessive oil out the relief tube and mostly by smoke in the exhaust due to the turbo dumping oil when the case pressure started to climb. (relief is only a -4 line)
My only problems now are fuel burn - I am seeing 20-50% worse fuel burn than my lyc buddies. That is likely due to excessive cooling drag and lack of refinement of timing and mixture.
But I did fly up to the Mammoth (ski area) on monday and flew home the same day after a full day on the slopes. Fought a head wind in the AM but was seeing 240kts ground speed on the way home.. Cool! I true out around 180kts now adays. We skiied until the slopes closed and were home for dinner. Cool!
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
On Feb 6, 2008 11:35 AM, Don Walker < drwalker@gbis.com> wrote:
I haven't figured out the engine mis yet, but it
may be somehow related to the fact that the intake manifold pressure is all over
the place. With the top cowl off, at 3200 rpm I am getting a range of
12.6 to 13.7. With the top of the cowl back on, it's a little
higher. Can't remember exactly. I got thinking about this and
figured that there is a manifold leak. I did pressure test it and fixed
all the minor ones before I cranked it over the first time. Then I
remembered that some people had to put dampners in the line to damper what I
think are pulsations from the prop. My throttle body is only 4 inches from
the prop. Couldn't find anything in the archives about this, so picked up
2 Brigs and straton aftermarket fuel filters to see if this will do the job by
putting them in the MAP line to the EC-2. I'll try them out this
weekend. I'm fixing the obvious stuff first and then moving to the
difficult stuff. All plugs firing well in mode 8. Still getting the
mis at all RPMs. I will see what happens after the dampners. Anyone
have any other suggestions out there? Also, I am getting a fair
amount of blowby out of the crank case breather tube at 4500rpm. What
are others doing about this. Again, nothing in the
archives.
Don Walker
RV-Renesis
N113BR
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