Ignition Book

[Neville Newman]

i dyno-tested an early Jacobs ignition (it was definitely the non-computer
version) on my Fiat X1/9, compared to a Marelli Plex electronig ignition
(no multi-spark, no CD).  The engine was definitely not new - i built it
3 years before and it had about 5K miles and lots of autocrosses and track
time on it.  i know the chambers were dirty because when i first bolted the
engine together, i could run 20 degrees static advance with no detonation
on pump premium, and i definitely can't do that anymore.

On the same night, i saw no difference in performance between Jacobs,
Marelli (with Lodge plugs), or Marelli (with Splitfire plugs - waste of
money).  The numbers were all within our window of error on the dyno readings.

However, what i've seen in the recent Jacobs ads is a description of a
system that sounds a *LOT* like the new one from SAAB, which uses "continuous"
resistance measurements over the plug gap to determine what to do on the
next firing cycle.  Of course, if this is what Jacobs is doing, they can
still only modify the ignition based on the feedback.  SAAB, on the other
hand, can modify ignition/fuel/boost all at the same time.

About 1 1/2 years ago, i saw a short engineering note on the SAAB system
in one of my car mags (R&T or Autoweek).  They used the new system in a
test in Los Angeles.  The measured emissions (O2, CO2, CO, HC, NOx) were
cleaner coming out the tailpipe than the air that went in.  Even more
amazing was the followup shock-factor demonstration, where they fed the
same engine's inlet from the tailpipe of a running SAAB 96? 2-cycle
motor.  The output was still within CA-legal emmissions limits.

If Jacobs really patented this technology, as he seems to claim, then
he'd be shouting from the rooftops that he had licensed it to SAAB.
If he didn't invent it, then i doubt that he could afford to license
it from SAAB.  Either way, it leads me to believe that his recent ads
are claiming something which is patently false (pun intended).


							-neville