Plug Wire Resistance

[Y-TRY]

What's the best way to check plug wire resistance?



What is an "acceptible" resistance for a high performance?

What wires last the longest in high-heat situations, without deteriorating?

[David Pozzi]

1. with an ohm meter. Some bad plug wires will make a snapping noise either in the wire (internal arcing) or you can hear it in the distributor cap. If one wire is bad, the others should be changed too. GM HEI systems can kill plug wires quicker than normal ignitions.

2. should be below 15,000 ohms if I remember right.
3. I'd look for a silicone wire set, with spiral wrap around a magnetic core, magnicore is one of the names, but look for any of that type since they are what David Vizard likes.
David

[Blown353]

Resistance will depend on the style of wires you run. Factory carbon-core wires can be 5000 ohms/foot, your typical "performance" spiral-core wires are usually 300-500 ohms per foot, while the "low resistance" wires are typially 20-50 ohms per foot. (The low resistance wires are usually noisy from an EMI standpoint and I have never seen any gains with them even with back to back dyno testing, so I don't run or recommend them.)

What I would do is yank all your wires then measure their length and measure their resistance with an ohmmeter and calculate the resistance per unit length of each wire. Any huge variations will indicate a problem, either at the crimped ends or in the wire itself.

As far as high-heat situations, best you can do is order silicone jacketed wires (almost all of them are, I like Moroso and Taylor standard resistance spiral cores and would recommend you buy Magnecor if money isn't an object) and then on top of that buy the additional fiberglass/silicone sheathing that MSD and Moroso sells to slip over the wires when you fab them; this gives them additional temperature resistance plus another 20kV of dielectric insulation. Unfortunately, a roll of the additional insulation usually costs just as much if not more than the wire kit itself, but it's worth it as you can re-use it on your next set of wires as long as you don't bake it.

Troy

[indyjps]

i was baking moroso wires on a drag car i had a while back (13:1 compr msd box with two step rev limiter) and switched over to taylors and had very good luck with them, i tested them each week prior to runing i was coing thru 3 sets of moros wires a season and the taylors lasted all season and still tested good.

[gmachinz]

Taylors have a patented material made by DuPont that eliminates the need for "baking/wrapping on extra fiberglass sheathing"-their material is the best at being heat resistant. I vote for Taylor based on personal experience with sprint cars. The 409's are 10.4mm and their ThunderVolt50 wires are 8mm but retain 409 standards to give it a stock appearing look for people in stringent race classes.My 409's are going on their 10th year (and 4th motor) with no change in resistance which is at 56 ohms per foot avg. That's pretty good in my book. -Jabin