And usually the stranded stuff is oxygen free copper or of higher quality due to lower impurities in the metal used...

This holds true in most applications...not just automotive...

 

You are referring to the "skin effect".
http://en.wikipedia.org/wiki/Skin_effect

It has to do with the parasitic inductance of a wire creating a small magnetic field which pushes the charge carriers to the skin of the conductor.

It is well understand and has no relevance to anything other than high current, high speed AC circuits. It is not by any stretch of imagination a "general rule" that applies to all wiring applications. Most of the time, its not even worth thinking about. I am actually quite skeptical it is anything even close to a dominant factor in plug wires.

In my experience as a EE, the biggest reason for stranded cables is easy bending. There is a lot of marketing BS that goes around to confuse people to the real facts of wiring and cabling (esp. in the audiophile market) and this stranded cable myth is one of them. Also, "oxygen free copper" == marketing BS.

 

Negative, I'm referring to the Farady effect on DC currents.

considering neither spark plugs nor any other source in the car uses AC I don't know why AC physics would come up.

 

Exactly. They don't. That was my point. The skin-effect is not applicable.

Stranded or not, all those little strands are shorted together anyway unless you're talking about Litz wiring -- in which there is a dielectric layer inbetween each strand.

Saying electricity is transmitted only on the surface area of conductors is perhaps the most ridiculous thing I've heard in a several days. Are you certain you still want to believe that?

Care to explain the Farady effect? Sounds like you've read one too many Monster Cable packages or are confused about capacitance and the unit of capacitance ("Farads") perhaps? Sure there is parasitic capacitance in all wires, but do you have any idea how little it actually is and how it is absolutely *not* related to stranded/unstranded wires in any appreciable way?

 

I put on Mazsport wires on my car and new NGK copper plugs all trailing on my car , and I am pretty happy with th results. Cleaned up sparatic idle , has more punch now in mid to high end range, and now i can chirp 3rd gear again.

 

Really? Soooo...just to be absolutely clear...what you are saying is...

A metal with impurities conducts better than a metal with little to no impurities??

Is that what you are saying??

 

Not exactly. It conducts better, but only perhaps 1% so. As an engineer, this makes it 1% more valuable to me which is not even enough for me to care. There's worse tolerances in just about every other component in an electronic design: MOSFET Ron resistance, resistors, capacitor capacitance, and -- for audiophile -- resistance of the nominal 4 or 8 ohm voice coils.

Let me put things in perspective for you.

1000 ft of 12 gauge wire is nominally 1.619 ohm. If this was "oxygen free" it would be 1.603 ohms. 1000 ft of 10 gauge is 1.018 ohms. You can get the same benefit by making your cable 1% shorter. I could go on and on about the absurdity of 16 milliohms per 1000ft if you want me too...

Many audiophiles are idiots (or sheep, depending on how you look at it) regarding
cabling. Don't believe the hype-- do the math!

 

Err...I can care less about the "oxygen free" term as much as that usually means the metal has been basically cooked hot enough to remove a majority of impurities...which while I agree that in terms of conduction its "meh" at best...it none the less is a minor increase and a welcome one regardless.

The primary reason you want a "processed" cable is because removing the impurities from copper generally translates to a softer much more flexible cable which should have a minor increase in its ability to conduct...

 

I think the primary reason you'd want a high grade copper cable is not because of anything objective, rational, or scientific. Its like jewelry. The item takes on more value because its more expensive and has a good marketing angle. The potential customer base eats up anything sounding "technical" because they like to think of themselves as intelligent techies.

I don't know about you but I don't buy cables based on how soft they are as long as they are soft "enough". The best "angle" IMHO for selling high grade copper is still the increased conductivity-- which is negligible in most applications. However, the majority of "techies" have no sense of scale so they round up a negligible increase in conductivity into significance.

I think the majority of the "high-end" cable industry should just accept the reality of what it is-- a technical fashion industry. If I didn't know any better, I'd think you were selling cables. I mean -- come on -- oxygen free high grade copper is better because its softer now???

If two cables are the same price, same gauge, same length, same manufacturer -- I'd probably pick the one made of oxygen-free copper. Actually -- I'd probably pick the one closest to my hand at the time. The difference isn't even worth me reading the packaging to find out copper purity-- I'd save the time and go home 15 seconds earlier.

 

Sorry to bring this thread back to life, but whats the difference between 8.5mm and 10mm wires

 

8.5mm wires are 8.5mm in diameter and 10mm are 10mm in diameter.

 

DailyDriver,are you saying you use trailing plugs in the leading position as well ?

 

is there anything different besides the size? Like performance wise?

 

Only that 10mm wires are less prone to "arcing", like when you have very old leads that have cracks in the rubber insulation,you can see the spark shorting out on surrounding metal parts ,they are used mostly in racing applications with very high secondary voltage such as magnetos,in IMO,10mm arent needed on the 8

 

ok, thanks for clearing that up for me

 

Quality wires not only have thicker conductors for better electrical conveyance but also better insulation. Insulation becomes electrically porous over time causing cross/misfires so better quality extends reliability.