Severe-Duty Spark Plug Wire Sets - Handmade in the USA With Military/Aerospace Components & Methods

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Electrical Characteristics

Core & Conductor

Electrical Characteristics

Resistance per Foot

  • OEM Suppression Wires: 400–1,000 Ω/ft (carbon core, resistive).
  • Generic “Performance” Wires: 25–50 Ω/ft (spiral-wound metallic).
  • Stage One IndestructaWires:
    • Suppression Core (10 mm): high resistance, EMI-dampening, tuned for radio silence.
    • Low-Ohm Core (8.5 mm): typically <5 Ω/ft — stronger spark delivery, less noise suppression.
  • Shielded IndestructaWires: ~0.04 Ω/ft — essentially negligible. Allows coil energy to reach the plug without resistive loss.

Capacitance & Inductance

  • Plug wires aren’t just resistors — they also behave like capacitors (core to jacket) and inductors (length of wound conductor).
  • Higher capacitance = greater tendency to couple noise into adjacent wires (crosstalk).
  • Shield braid reduces this by creating a grounded barrier, lowering effective capacitance seen by nearby wires.
  • Result: cleaner signals, reduced chance of “#5/#7 crossfire” in V8 layouts.

Dielectric Strength

  • OEM EPDM jackets: ~15–20 kV breakdown.
  • IndestructaWires insulation stack: >50 kV breakdown — providing huge margin above even high-energy CDI systems.
  • In practice, this means no corona discharge, even in boosted/nitrous builds where plug gaps are opened up.

Frequency Response (EMI Perspective)

  • Ignition noise contains harmonics from ~100 kHz up through tens of MHz.
  • Suppression cores damp this by resistive heating (wasted energy).
  • Shielded IndestructaWires reduce it by containment, typically 20–60 dB attenuation depending on frequency.
  • Translation: less noise across radios, sensors, and nearby harnesses without throwing away spark energy.

Coil Compatibility

  • Inductive OEM coils: works seamlessly with suppression or low-ohm.
  • Performance/HEI/MSD coils: benefit from low-ohm or Shielded sets to ensure maximum coil energy makes it to the plug.
  • CDI systems: especially benefit from Shielded sets, since CDI pulses are short, high-energy spikes with wideband EMI. The shielded braid contains those spikes without resistance losses.

In Plain English

  • Stage One (suppression) = quieter, rugged wire, like OEM on steroids.
  • Stage One (low-ohm) = stronger spark, a little noisier.

Shielded = the best of both: near-zero resistance for spark delivery, and a grounded braid to kill the noise.