Spark plug wires

[The407n00b]

I see on spark plug wires that like 7mm 8mm 9mm etc.

is that like the amount of spark or millimeter what is that representing and the more the better?
I have some bosch 7mm's or something

[ksniperfox]

that means how thick each spark plug wire is. bigger does not mean better, but the idea is, the bigger the wire means less resistance from distributor to spark plug.

stock size is fine. you can get 8mm or 8.5mm if you wish but theres really no point to spend extra money on them.

[Sirfallsalot243]

You only need bigger ones if youre putting out big power. If you arent, it will take more energy to send the electricity through the wire than youre gaining by having a bigger wire, and is actually hurting you.

[ksniperfox]

Originally Posted by Sirfallsalot243

You only need bigger ones if youre putting out big power. If you arent, it will take more energy to send the electricity through the wire than youre gaining by having a bigger wire, and is actually hurting you.

while were on the topic, i am seriously considering a full MSD setup that will come with 8.5mm superconductor wires. this cant hurt me can it, since i will be using a 6a box, blaster coil, and power cap altogether for setup in sig?

[Sirfallsalot243]

Originally Posted by ksniperfox

while were on the topic, i am seriously considering a full MSD setup that will come with 8.5mm superconductor wires. this cant hurt me can it, since i will be using a 6a box, blaster coil, and power cap altogether for setup in sig?

You can do it if you want, but MSD reliability sucks, and you have absolutly no need for it. OEM ignition is fine until around 450whp.

[The407n00b]

THank you very much guys.

[James777]

i don't think the OD of the wire has anything to do with the conductor.

james.

[NoSkillz]

Originally Posted by Sirfallsalot243

You only need bigger ones if youre putting out big power. If you arent, it will take more energy to send the electricity through the wire than youre gaining by having a bigger wire, and is actually hurting you.

How so?

[Sirfallsalot243]

Originally Posted by NoSkillz

How so?

Everything that conducts electricity has a certain resistance to carrying the charge. Thats why we use copper for wiring, because it holds a charge well with little resistance. But the more material there is, the greater the distance the electricity has to travel. Since a 7mm wire will have the same resistance has a 9mm one, it takes more power to get the same charge through a larger wire because there is more material for it to travel through. If this werent the case, wouldnt we be using 30mm wires?

[the texan]

Originally Posted by Sirfallsalot243

Everything that conducts electricity has a certain resistance to carrying the charge. Thats why we use copper for wiring, because it holds a charge well with little resistance. But the more material there is, the greater the distance the electricity has to travel. Since a 7mm wire will have the same resistance has a 9mm one, it takes more power to get the same charge through a larger wire because there is more material for it to travel through. If this werent the case, wouldnt we be using 30mm wires?

That is incorrect. The thicker the diameter of the wire the LESS resistance to electrical flow that wire will have. Though I should note that I mean the conductive part, if the insulating sleeve is just thicker this doesn't apply.

There are many reasons why people don't use 20 or 50 or 500mm wiring, but the most obvious is that nothing anywhere near that thick is necessary. Heavier gauge wiring is more expensive, less flexible, harder to shield and difficult to mate up to the narrow spark plug and distributor cap terminals vehicles are designed with. The gain from such thick wire is also inconsequential, 7mm wire is actually decently thick for the amperage your ignition system is flowing.

[Sirfallsalot243]

Youre right, my bad. I looked it up. However, a certain amount of electricity is still lost by running through a copper wire. Copper has
a resistivity of 17 nano ohm meters. This is constant, so the more copper (distance) it has the go through, the more current will be lost. A long thin wire made of copper will have a moderately high resistance. A short thick wire made of copper will have a low resistance. But think of it in terms of water in a pipe. Electrons are like water, voltage is like pressure, and current is like flow rate (ie., gallons-per-minute). If the pipe doesnt have enough pressure (voltage), it would be pointless to upgrade to a bigger pipe.

Im glad you made me look that up- i learned a lot.

[the texan]

Originally Posted by Sirfallsalot243

Youre right, my bad. I looked it up. However, a certain amount of electricity is still lost by running through a copper wire. Copper has
a resistivity of 17 nano ohm meters. This is constant, so the more copper (distance) it has the go through, the more current will be lost. A long thin wire made of copper will have a moderately high resistance. A short thick wire made of copper will have a low resistance. But think of it in terms of water in a pipe. Electrons are like water, voltage is like pressure, and current is like flow rate (ie., gallons-per-minute). If the pipe doesnt have enough pressure (voltage), it would be pointless to upgrade to a bigger pipe.

Im glad you made me look that up- i learned a lot.

Agreed, while it is technically true that larger wires offer less resistance, this is just used as a marketing ploy by aftermarket manufacturers to sell their "upgraded" wires. While additional shielding or heat resistance is certainly a true selling point, additional core thickness simply isn't necessary at the power levels our ignition systems create. But that won't stop people from telling you it'll help

[NoSkillz]

Originally Posted by the texan

That is incorrect. The thicker the diameter of the wire the LESS resistance to electrical flow that wire will have. Though I should note that I mean the conductive part, if the insulating sleeve is just thicker this doesn't apply.

There are many reasons why people don't use 20 or 50 or 500mm wiring, but the most obvious is that nothing anywhere near that thick is necessary. Heavier gauge wiring is more expensive, less flexible, harder to shield and difficult to mate up to the narrow spark plug and distributor cap terminals vehicles are designed with. The gain from such thick wire is also inconsequential, 7mm wire is actually decently thick for the amperage your ignition system is flowing.

nicely put, i was gona get technical but u did the job far better, im glad my short question helped produce a proper answer.