Fly Bum wrote:

 Figured you folks would be the best to answer this? I
 have the opportunity to buy an affordable plane but it
 has a two-stroke Rotax 582 with carbs.  I would like
 to add a fuel injection so that I can control the
 mixture (I will be operating at a variety of
 altitudes) and also so that I can hopefully improve
 the fuel economy.

 I was reading about semi-direct injection and came
 across the following? ?This bring us to Ski-Doo SDI -
 a quite different and more economical route [vs DI or
 HPDI] to low two-stroke emissions and fuel
 consumption. SDI stands for Semi-Direct Injection, and
 it describes a system by which fuel is injected, not
 into the combustion chamber, but into the fast-moving
 air streams in the rear transfer ports. Because
 injection into the transfer streams more than doubles
 the amount of time available for evaporation of the
 fuel droplets?.. Cylinder head and piston crown do not
 have to be redesigned to work with SDI (they do with
 bi-modal DI), and ordinary automotive-type fuel
 injectors, working on a normal 60-psi injection
 pressure make no call on high technology.?

 So is it possible to use this technology (or at least
 some fundamental principles from it) in conjunction
 with Tracy?s controller to get better fuel economy
 from the 582?

 Where is the best place to inject- straight into the
 port or just downstream of the throttle body?  Also,
 better to use a single throttle body and split the
 flow (how evenly?) or use smaller dual throttle
 bodies.

 Thanks folks.

 > Joa

  I am into snowmobiles and I use an adjustable needle kit that screws
into the drain plug of the carb, it is operated by a speedometer
cable, it works great and a hell of a lot simpler that going to
injection and less to go wrong.
  Also there is a kit that adjusts the pressure on the air correction
jets that works good and the late model snowmobiles use a automatic
alt adjusting carb that is computer controlled.
  They tried injection on snowmobiles and it didn't work out.

  Ken Welter

 
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