Re: DIS for GMECM

[Len Sabatine <sabatine@epix.net>]

   Think , elimination of distrib gear , rotor ,cap , carbon brush , air gaps
    slop in the timing sys , ionization ,torsional vibes traveling thru cam,
    oil pump disturbances , coil and plug wires and their routing. All the 
monkey
    motion and associated spark delivery problems , GONE, especially with
    CNP ignition sys. Spark scatter and inductive X fire tendencies , GONE.
    " Nearly" perfect spark delivery and repeatability is now possible . 
Add to
   that , Coil drivers are on each coil , not on PCM Motherboard. A very high
   degree of "recovered loss" in Ignition efficiency has come to pass. The
   ms latency ,spark propagation time has also been reduced substantially.
    Hope I've gotten the idea across.
    Len

> So the benefit to going w/o distributor is to prevent missed/deformed
> sparks?  I always figured it was to get better timing accuracy.  I sorta
> figured you'd get more energy jumping the spark gap with coil-per-plug (is
> there a industry buzzword for this?) than with systems that use
> conventional ignition wires.  Is this not the real reason?
>
>  On Tue, 5 Dec 2000, Bruce Plecan wrote:
>
> >
> >
> > Allz said and done, DIS will get you about a 2% less misfire rate.
> > Meaning thou the AF mixture was lit, the flame front for what ever reasons
> > was unusual, and genereated less energey for that event.   Not to be
> > confused with a *miss*.
> > Coil per Plug can get you an addition 1% improvement, and get right near
> > 100%.
> > Bruce
> >
> >
> > > As best I understand it DIS allows a longer dwell (charge time) for a
> > given
> > > coil at higher RPM's, resulting in a hotter spark.   You also eliminate
> > the
> > > wear of air gaps at the distributor caps.   Less moving parts, less
> > failure
> > > points is good from the OEM point of view.
> > > Also, advance is "unlimited" since you don't run into rotor phasing
> > issues.
> > >   This still confuses me, since it's my understanding that there's almost
> > > no app that you would want more than 45 or so degrees of advance anyway,
> > > from the tone of a lot of messages recently.
> > > -> Bob Valentine
> > > -> bob@tecmark.com
> >
> > > At 06:51 AM 12/5/2000 -0800, you wrote:
> > > >DIS=Distributorless Ignition System?
> > > >So what's the point of trying to get a "DIS" working on an AUJP/730 
> if my
> > > definition of DIS is
> > > >wrong?  Explain to me why there is this holy-grail of getting DIS 
> running
> > > on a V8/730.
> > > >Squash
> > > >--- Chipsbyal@aol.com wrote:
> > > >> This is not a DIS system as it is a distributor less system. This is a
> > CNP
> > > >> coil near plug system. Each cylinder has its own ignition module, coil
> > and
> > > >> plug wire. The interface that was at the show only drives the separate
> > > >> modules. Speed Pro also had an interface to use this CNP ignition for
> > > their
> > > >> systems.
> > > >> AL
> >
> > 
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>
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