In a message dated 10/31/2009 1:30:01 P.M. Eastern Standard Time,
szpejankowski@GMAIL.COM writes:

That's a  very broad question that would take a book to answer. There
some decent  write-on the subject you can find on the web.

hello Doesn't seem so broad to me.  both are just control  systems.
digijet only uses the brain to control the fuel injection  and probably rev
limiter,   this system has a seperate control system  for ingnition, same as that
used on a lot of earlier Vws and other european  cars,  Digifant uses the
computor to do both fuel and ingnition , at least  on the vannie .   neither
has a knock sensor used on them. I know  the idle system is different but
that is easy to change from one to the other,  as I used the old system that
was on my 85 when I installed the 1.8L jetta into  it. So other than that
what is the difference,  It has nothing to do  with which engine you are using,
 1.9 or 2.1 WBX or inline jetta  1.8L  as I have interchangesd all of these
motors.   Is one system better  than the other??  I personally preferr the
digijet , but that is just  me.  I have both systems as my 85 has the
digijet with the 1.8L jetta motor  and my 86 syncro has the digifant.    later
mark  d