Re: Jacobs et. al.

[PDQSHIP@aol.com]

In a message dated 96-08-24 16:24:37 EDT, you write:
The primary consultant in the article is Dr. Chris Jacobs, Phd, EE.  Dr.
Jacobs
is described in the article as "the brains of Jacobs Electronics".
Unfortunately, the article identifies him as a independent source of
information
on spark plugs.  Being the cynical guy that I am I take issue with a premise
or
two in the article, but in general the info is good.

Generalizing a few points here:  The amount of voltage required to jump a gap
is
directly related to the amount of energy in a spark.  The more energy in a
spark, the more energy available for combustion; therefore more power is
available from a given fuel/air mix (more complete combustion).  The
conclusion
would appear to be the higher the spark voltage, the better.  

The article describes the primary drawback of high voltage plugs as misfires:
the ignition system (from coil to plug, inclusive) is often unable to
reliably
produce a sufficiently high voltage to generate a spark on a regular basis at
high rpm.  

According to the article here is where you gain your benefit from platinum
plugs:  low arc-over voltage requirements (the amount of energy required to
spark) in platinum plugs reduce the amount of misfires in an engine with a
weak
ignition system.  The article then describes the various triple electrode or
crows foot plugs as mechanical attempts to due what the platinums do
chemically:
reduce the arc-over requirement. 

I'll agree with the article to here, with a disclaimer: If the plug gap were
the
same, this would be true.  Different gapping, different results.  Long term
would also yield some side effects: plug life, etc
<< This discussion left out some of the other aspects of plugs:  durability,
 potential to foul, etc.
 


Hmmmmm....  I remember a call from Ned asking me to call one Carl Jerritts
re: his boost prollum on his massively tweekd 5ktq....  First rule, I always
ask what was done to said vehicle, low and behold Dr. Jacobs managed to find
a home for one of his Hi Energy Ignition systems right into Carl's car.....
  This being the third audi owner sirened with said tweek, instructions were
easy:   Take the system out and call me in the morning.....   As with the
other two, car regained it's power with the stock coil....  So, me, I would
question anything the proclaimed docktor might prophet......  A stock Bosch
coil is fine for the I5 turbo, run with the FD5POR for the ultimate in plug
comfort (tho not price), get yourself a set of single electrode coppers as
second choice.....  Blowout of spark on a turbocharged audi?  Doubt it on the
most tweeked of 10v turbos, possible I spoze, with a 20vturbo motor tweeked
to the hilt, but currently the aftermarket seems to be stopping with 350hp in
that config anyway.....  

Jacobs and a quart of Slick 50  will get you a slimy zap in the wallet....

Scott