[Miata] Spark plug wire routing

[Larry Alster]

Actually I'm going to completely disagree here.

Running wires parallel allows the field from one to be repeated into the
other wire.

I was taught all along that you make sure the wires cross because it cannot
induce a voltage into the other wire when it crosses it.

Proved it many times through the 70's and 80's with hi performance American
V8s with high voltage ignition systems by stopping misfires by rerouting the
wires.  I see no reason why the Miata wires/ignition should be any different
and I've always made sure my wires are routed to cross each other with no
ignition issues.



Larry
 
White Knight      1991 Crystal White   #99 CSP
Silver Bullet        1992 Silverstone     #17 SM2  FM I+ Turbo
Honey B             1992 Sunburst Yellow #99 SM2L  JR Supercharger
Whooosh           2004 Titanium Mazdaspeed MX-5
 
LowCountry Miata  http://www.lowcountrymiataclub.net
Masters Miata
RAGS 074


-----Original Message-----
From: miata-bounces at realbig.com [mailto:miata-bounces at realbig.com] On Behalf
Of Mullen, Tim
Sent: Wednesday, May 28, 2008 11:38 AM
To: MiataList
Subject: Re: [Miata] Spark plug wire routing

Derek Marshall wrote:
>
> I have heard two different stories regarding routing of the
> spark plug wires on Miatas. 1) Route the wires separately in 
> parallel as per the plastic clips provided, or 2) wrap the 
> wires around each other to cancel out induced EMF or 
> whatever. 

Run the wires the way the factory intended.

In any car, you should try to minimize any "crossing" of the wires.
When wires cross, the magnetic field from the electrical current can
induce a current in the second, crossed wire (and also reduce the
current in the first wire).  So, running wires parallel is the best way.
Wrapping the wires around each other would be a bad idea.  I can see
where the idea might come from - network cabling uses twisted pairs of
wires to minimize induced "noise" on the wires.  But this is to reduce
external interference (induced currents) from other sources, not the
wires themselves (the interference sill distort the data on the wires).


In the case of the spark plug wires, we are not concerned about any
"noise" on the wires, we don't want any false currents being generated
that may cause sparking problems.

Tim Mullen

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