No Subject

[mcherriman at aesprodata.com.au]

     Hello,
     I am building a simple MAP controlled system for a 2litre turbo.  It 
     is micro-controlled and basically fires each injector with the spark 
     signal, and the duration is based linearly on the MAP output.  There 
     is also a 3d correction table which gives a correction factor for RPM 
     and MAP (to adjust mixture, and to compensate for changes in 
     volumentric efficiency with rpm & boost).  This works quite well, but 
     I dont know what mixtures should be used theoretically at boost.  I 
     have assumed a 14:1 mixture at light loads (about 1/2 bar absolute) 
     and 12:1 at 1 bar (absolute).  Presumably I should keep enrichening 
     the mixture as boost increases, but what to!!!  (I am ignoring 
     volumetric efficiency changes with rpm at the moment)  My aim is 1 bar 
     boost pressure, so does anyone know approx. what mixtures you should 
     use at this level with an intercooled motor.  It must level off at 
     some point (maybe 8 or 9:1). I have heard that turbo motors like very 
     rich mixtures under boost.
     Any help appreciated.
     Mark.