Date:         Wed, 13 Mar 1996 13:59:27 -0700
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         "Michael A. Radtke" <m.radtke@elm.az05.bull.com>
Subject:      RE: MSW plug wires

Dan et al,

I don't remember the MSW as a brand name.  However, several manufacturers 
make this type of wire.  I think Borg Warner and Belden are among them. 
 They are "distributed inductance" rather than "distributed resistance" 
wires.

The purpose of the resistance in a plug wire or plug is to slow the spark 
voltage rise time.  A fast rise in voltage is radiated like a radio signal 
and causes ignition noise in your radio.  Many areas have laws requiring 
"noise suppression" ignition wires so the police car next to you can use 
the radio.

The "distributed inductance" wires actually have a poor (lossy) inductance 
that slows the voltage rise time by absorbing the energy of very fast 
voltage changes.  This lossy inductance is a better approach than the 
resistance method because it doesn't reduce the current of the actual spark 
as the resistance approach does, and makes the wires tougher as well ... 
the resistance is delicate.  The down side is only that they cost more to 
manufacturer.

End of lecture.

Mike


Michael A. Radtke  -  Z74               Voice: 602-862-4897
Bull                                      FAX:         4853
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