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 Post subject: Re: PLUG WIRES
 Post Posted: Mon Aug 16, 2010 3:31 pm 
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Yes I had thought about corrosion and skin effect as the cause before but I'm not sure if it's just that. Technically the magnetic field carries the energy and with spirally wound wire the air core may be affected by changes to the inner structure over time and the outer field will be affected by metal proximity. I don't know why they don't make wires with inner metal cores, that would seem to make sense to me. It would reduce losses. People think that putting the coil straight onto the plug solves those issues but the coil on plug stuff are rubbish coils, no guts to the spark and they fail the coil even in standard cars. Just junk. Engine electronics is made to be cheap maximum profit and its rubbish, why cant we get good long lasting components, at the price they charge for them they should be. Anyway back to plug wires.
I think that the effects of corrosion are a movement of oxidized atoms into the surrounding insulation material and that is basically a contamination of it, altering the magnetic field 'purity' for the lack of any other word. When you scope different brand wires and old ones etc what you see are changes in consistency of spark profile. A distributor ignition system is going to have variances in rotor gap etc every time it turns (there is bearing play etc) the gap is the main source of energy loss and the energy that gets transmitted during the duration phase of the arc varies more with some brand wires than others. That energy is essential to combustion consistency especially on engines with a bit more turbulence in the arc zone than others. You can test a standard car engine all you like with fancy wires and the differences are hard to detect but modified engines always have combustion inefficiency and they are more reliant on getting the start of the combustion as good as possible. Hotrod engines make a lot of power but they are not efficient at fuel utilization.
Some engines rely heavily on the spark energy to get the combustion underway, often I see combustion not started until the arc discharge is nearly all over and done with. So small efficiency changes in the wires on those engines makes a big difference. New wires will make them run smoother due to improved regularity of cylinder pressure ramp rate.


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 Post subject: Re: PLUG WIRES
 Post Posted: Mon Aug 16, 2010 6:47 pm 
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Some has to do with the fuel used as well. Nitro cars use dual plugs and magnitos to fire the large volume of fuel used. Also an interesting post on ignition and E85 here.

http://www.yellowbullet.com/forum/showt ... p?t=271288

Also not sure a metal core is a good idea, might absorb some of the energy in creating a long magnet out of the core. And want to stick to everything. =; The primary reason for winding the wire is to make an inductor out of it to reduce or eliminate RF from being generated. Inductors will pass DC but will hinder AC increasing as the frequency increases.


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 Post subject: Re: PLUG WIRES
 Post Posted: Mon Aug 16, 2010 6:57 pm 
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So why then is it not recommended to use straight wire leads on CDI? And what effect does having the wire in a coil have on the oscillating voltage of multiple spark?


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 Post subject: Re: PLUG WIRES
 Post Posted: Tue Aug 17, 2010 4:51 pm 
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Straight wires produce large amount of EMF and RFI, newer electronics in even race cars would go haywire. But you already know that. Secondary side firing is DC, the oscillations are a byproduct. Just like a water hose, if you put a gauge at the source the pressure would spike if the nozzle was closed quickly. It would be interesting to see the differences on a scope in conductors, straight and wound, and new and old cables, especially with a multi spark ignition. Have not had access to an automotive scope for over 20 years, and never got around to converting my 150 mhz scope to use. Another note, some of the deterioration may just be at the connectors. Trim the ends and new connectors might perk them back up.


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 Post subject: Re: PLUG WIRES
 Post Posted: Tue Aug 17, 2010 6:13 pm 
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Yes i realize that about EMF etc but BMW do some things that are really against the rules, I dont know about their new cars now days but inline motors like 6's and 4's in the 80's and early 90's had straight copper wire leads, no windings for EMF, just straight wire and they also ran them all in a plastic or metal conduit over the years. NO cross fires, ive even run them on MSD with no cross fires. So it makes you wonder sometimes about 'rules'.


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 Post subject: Re: PLUG WIRES
 Post Posted: Tue Aug 17, 2010 6:48 pm 
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shrinker wrote:
I dont know about their new cars now days but inline motors like 6's and 4's in the 80's and early 90's had straight copper wire leads, no windings for EMF, just straight wire and they also ran them all in a plastic or metal conduit over the years. NO cross fires, ive even run them on MSD with no cross fires. So it makes you wonder sometimes about 'rules'.


What does a scope trace look like on those engines compared to a standard vehicle ignition?


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 Post subject: Re: PLUG WIRES
 Post Posted: Tue Aug 17, 2010 6:52 pm 
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never done one. But there just a normal electronic inductive ignition.


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 Post subject: Re: PLUG WIRES
 Post Posted: Tue Aug 17, 2010 9:14 pm 
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WOW this has gone way over my head. But very interesting reading. Thanks for all the info you guys ROCK \:D/ \:D/ \:D/ Any way I put a new set of MSD wires we will find out this weekend how they do or even if that was my problem.. Thanks kenny

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 Post subject: Re: PLUG WIRES
 Post Posted: Tue Aug 17, 2010 11:21 pm 
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Metal conduit in itself is a shield to RFI and EMF, plastics can be made to do the same. As long as there is a good non conductive insulator between them that may allow them to use straight wire. With audio, we do the opposite. The wiring we use has a foil or braided shield outside of the conductors that carry a very low voltage mic signal. They can be susceptible to picking up RF interference, I've had long cable runs pick up a radio station RF signal and convert it to an audio signal when the shield is broken. I do wonder if the wound core's dampening capability of AC is beneficial to some of the ignition systems, especially with a MSD style ignition.


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 Post subject: Re: PLUG WIRES
 Post Posted: Sun Sep 05, 2010 9:57 am 
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This discussion reminds me of college...............great info though. Gave me a headache too, to early in the morning to think electrical theory and principals! I need a good sniff of nitro, that will clear it up!!! [-(

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 Post subject: Re: PLUG WIRES
 Post Posted: Sun Sep 05, 2010 5:08 pm 
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jmarkaudio wrote:
Metal conduit in itself is a shield to RFI and EMF, plastics can be made to do the same

On those BMW's all the wires are grouped together inside the one metal conduit and on some models its plastic. So they just shove all the wires together against all the 'rules'.
During this last week I dynoed the race car engine on the engine dyno and I had my scope running on it. You know what?-- there is voltage induction into some of the sparkplug leads. Its got a msd 10 plus on it and there is quite high voltage induction around 1500 volts in some cases onto the non firing leads. All the leads are separated with those bar things etc. Not good. I have to fix it.


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 Post subject: Re: PLUG WIRES
 Post Posted: Sun Sep 05, 2010 5:15 pm 
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Ever try to Vid a fuel car on the starting line??? It will make your camera go haywire... :-

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 Post subject: Re: PLUG WIRES
 Post Posted: Sun Sep 05, 2010 8:38 pm 
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Beretta wrote:
Ever try to Vid a fuel car on the starting line??? It will make your camera go haywire... :-


That comes from the shock waves from the NITRO fuel. When every cylinder hits it produces a shock wave that actually shakes your body, which is holding the camera. That produces the blurred pic you see.

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 Post subject: Re: PLUG WIRES
 Post Posted: Mon Sep 06, 2010 9:12 am 
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Funny but the camera crew told me that it's from the mag on those cars as it does it to there camera's also #-o

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 Post subject: Re: PLUG WIRES
 Post Posted: Mon Sep 06, 2010 6:25 pm 
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took the mufflers off our car once and it blitzed the camera, mufflers on and its fine. the noise just shakes the camera internals.


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