Ed,

As others have said there's no performance advantage to the resistor
plugs.  All the resistor does is knock the square edge off the voltage
going to the plug. A square wave (or, more accurately, a spike-square
wave) contains all sorts of high frequency energy. In the old days that
didn't matter, but as electronics became more prevalent in the cars
there was a need to reduce the interference caused by the high frequency
energy (my father said it was a common way to "fix" AM radio reception,
to give an indicator of the early real need for the plugs). In our cars
the data acquisition systems are not happy with stray high-frequency
energy, so the plugs will help them out.

In Electrical Engineering terms, the spark plug is nothing more than a
high value air-gap capacitor that's pushed past avalanche point. If you
look at the coil output on the oscilloscope, you'll see an initial spike
as the voltage builds across the capacitor, and then a drop to a plateau
as the spark jumps & ionizes the air in the gap. The resistor in line
with the capacitor creates a simple RC circuit. The rise time is a
function of the resistance & the capacitance. Increase the resistance &
you'll increase the rise time....

-Ted

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of edward
capullo
Sent: Tuesday, July 10, 2007 7:46 PM
To: [email protected]
Subject: [F500] resistor plugs

I am curious to see if anyone has a strong opinion one way or another
about 
running resistor plugs with our engines. I have run B9EG and BR9EG and
do 
not seem to notice much difference. Does running one or another have any

real advantage or issues?
Ed Capullo
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