EST Systems

[dn]

> >>>My original idea was to use a GM EST distributor (ones with the 
> >>>locked rotor) and dump in a normal 4 wire module.   Set the physical 
> >>>timing really retarded, then just delay the impulse from the pickup to 
> >>>the module.    

This is the way the old analog delay systems worked  where  you  could
adjust  your  timing from a dashboard control (Accel, MSD used systems
like this).  Problem was, if it broke, your timing  was  way  retarded
and the engine probably wouldn't even run, much less limp home.

> the time to fire the coil (turn it off or make EST go low).  From this 
> subtract the dwell time (I haven't got any numbers yet) to determine the 
> risetime of EST.  I'm not sure but some modules might limit dwell time 
> internally.

When  you  say  "limit  dwell  time  internally", do you mean that the
module automatically turns the coil on again at some fixed delay after
EST has been triggered, regardless of the current state of EST? I'd be
dissapointed if this was the case, since  I  had  planned  to  have  a
variable  dwell based on RPM to keep the power dissipation in the coil
to a minimum. (still referring to the standard GM 7 pin module)

One other question: is the Refernce output of the module just a signal
conditioned copy of the pulse from the pickup? The  reason  I  ask  is
that  I also wanted to use the method of having one wider tooth on the
reluctor to indicate cylinder 1, thus having a  reference  for  engine
position.   If  the  Reference  is  a straight one-shot pulse of fixed
width regardless of what pulse width the pickup  sees,  I'll  have  to
scrap  that  idea  and  use  some  other  method of determining engine
position.

Regards, dn



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