Jim Mederer used a interesting technique to tune the turbo for
    aircraft use. Most turbos are designed for automotive use where
    fast spool up is necessary. The probelm with this is at high
    continuous aircraft power the turbine will over heat and or over
    speed and fail.

    What Jim did was use a controlled leak in the exhaust manifold to
    get just enough boost.

    Works better than a waste gate with low A/R turbos.

    This has a side benefit of reducing the exhaust back pressure. Less
    back pressure more power.

    Paul Lamar

    Hi Paul. I don’t understand! I thought a waist gate was a controlled
    leak in the exhaust manifold.

    Steve Izett

   Yes it is but it is a bit heavy and problematic.
   This  is much simpler and and lighter weight.

   The waste gate only measures the back pressure.
   This device respons to the ratio of back pressure to atmosperica pressure.
   I think it does a better job of keeping the HP matched to the altitude change.

   Of course the jury is still out until we fly it.



   Paul Lamar





   Paul,
      Is the rectangular tube in photos the "Controlled Exhaust Leak" ??................


    Kelly Troyer

Yes but it is but not that big. Up stream of that there is a one inch orifice.
To get more boost you go to 3/4 inch. Less boost 1.5 inch.
Simple, cheap and it works great.

A waste gate gives you more boost at low RPM. Not what you
need in an aircraft engine.

Paul Lamar


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