Paul,

    Did you measure the MAP for your p-port Renesis during the dyno runs?
      Do you recall the readings you got, particularly at idle speeds?  I'm
    questioning the readings I am getting at idle speeds (approx. 2k rpm)
    ... around 17".  I measure MAP at the old oil injection ports.  The
    three are teed together.

    Mark S.

    Sorry to not get back to you sooner Mark. We had severe email
    problems with earthlink servers.

    I don't recall what those numbers were at 2K RPM. I don't
    think we tested at that RPM. That sounds real high for only
    2000 RPM. What mixture are you  using at that RPM?
    Does the engine idle smoothly at that RPM?

    Is that a steam gage or electronic pressure sensor reading?

    Paul Lamar

Paul,

2K is where it starts running rough.  My wideband gauge quit shortly
after I had to switch to 100LL because of the ethanol mandate.  So, I'm
reading mixture off the EM-2.  Mixture is set to where it runs the
smoothest.  That is about half a bar on the EM-2.  Prior to p-porting,
the engine used to idle down nicely around 1500 rpm.  The engine runs
great at the higher rpms.

My suspicion is that the primary injectors (and idle) would work much
better if they were located downstream of the slide throttle.  I'm
currently trying to figure a way to test that theory.

Mark S.


I don't expect that will help much.
I forgot. Are you using a 2.85:1 or 2.17:1 gear box ratio.

2000 RPM idle is not bad for a p-port. That is 700 prop RPM with
a 2.85. My O-470 will not idle lower than that.
Are you having any trouble on approach?

If so try slipping. Slipping is safer and more accurate way of landing
as one can always extend the glide if you have an engine failure on final.

You should use one of these cheap high speed data aq as it can show turbulence in the intake manifold at low RPM. It is sampling at over
1000 SPS. About the response time of the pressure sensor Tracy
is using.

Paul Lamar