If you’ve ever heard a steady, high-pitched buzz, whistle, or rapid, cellophane-style crackling/ticking from under the hood, you’ve experienced ignition noise. In the world of high-performance racing and custom builds, managing this electronic chatter is just as important as tuning your fuel maps.
At its core, your ignition system is a small radio transmitter. Every time a spark fires, it creates electromagnetic energy that can interfere with your radio, GPS, and sensitive engine sensors. To keep your electronics clean and your engine running at peak performance, you need to understand how to manage this interference without sacrificing spark energy.
Why Ignition Noise Happens
Ignition noise, technically known as Electromagnetic Interference (EMI), is a byproduct of the high-voltage electricity required to jump the gap of a spark plug. When the ignition coil releases its energy, the rapid change in voltage can interact with sensitive radios and data systems - here's how it happens:
- The Spark Gap: The ignition system produces a voltage across the spark gap which produces a spark. This causes a large voltage change (dV/dt) and a sharp spike in the electromagnetic spectrum. The available charge (current) from the ignition system flows through the spark to ignite the fuel. This causes a longer-term current through the wires.
- The Antenna Effect: The spark breakdown and subsequent current flow through the ignition wiring produce radiated fields and conducted transients - your spark plug wires can act like antennas, broadcasting this spike to nearby electronics.
- Interference: The radiated fields and pulsed currents in signal and/or grounding circuits can interact with radios, etc. to produce undesirable effects. These effects could be due to interactions at the RF frequencies used (including high-speed computer processing), at intermediate frequencies (e.g., IF circuits), or at lower operational frequencies used in digital or analog processing.
The Conflict: Performance vs. Quietness
There is a natural tug-of-war between spark intensity and noise reduction. Standard road cars often use high-resistance carbon-core wires (around 10,000 Ohms per foot) to kill noise, but this resistance can also weaken the spark in a high-performance engine.
Factors Affecting Electromagnetic Interference (EMI) Severity
| Factor | Impact on Noise |
| Wire Resistance | Higher resistance generally equals lower EMI. |
| Wire Geometry | Large loops in wiring increase radiated noise. |
| Proximity | Keeping wires away from sensitive data lines reduces interference. |
| Grounding | Poor grounds act as gateways for noise to enter electronics. |
How to Avoid and Mitigate Interference
Achieving Electromagnetic Compatibility (EMC), a scenario where your ignition and electronics work in harmony, can require a strategic approach.
- Optimize Impedance: You want the highest resistance and inductance possible that still allows for optimal engine operation.
- Manage Wire Spacing: Keep your spark plug wires as close to the metal surfaces of the engine as possible. This uses the engine block as a natural shield. Avoid hot surfaces as this can melt and short out the wiring.
- Shorten Your Grounds: Ensure all ignition grounds are short, direct, and connected to the chassis with low-resistance terminations.
- Eliminate Ground Loops: Use separate ground paths for your radios or data systems to prevent 'dirty' ignition power from circulating through sensitive gear.
The Scott Performance Advantage
The good news is that at Scott Performance, we have done all the hard work for you. We offer spark plug wires engineered to bridge the gap between premium power and electronic silence. While generic wires often force you to choose one or the other, our construction focuses on specialized EMI mitigation.
We offer both vehicle-specific sets and universal kits that can be tailored to your exact needs. Our spark plug wires are offered in two distinct categories:
| High Performance Low Ohm - Optimized for power and made for racing. | Street Performance - Optimized for everyday performance and a massive upgrade over stock. |
| • 30 Ohm resistance rating* • Hi-inductance for racing and high performance applications • .090" diameter core for strength and low impedance • .004" pure copper conductor with our proprietary 200 turns per inch winding |
• 300 Ohm resistance rating* • 9MM diameter woven fiberglass sleeve is standard • Heat resistant to 1200°F • Good balance between inductance and reduced noise/RF interference • .065" diameter core • .006" copper alloy conductor with proprietary 125 turns per inch winding |
*Resistance ratings can vary as much as 10 ohms; we match sets to ensure consistency.
- Tailored Resistance: Our wires are designed to provide the specific impedance required to suppress noise while ensuring the follow-on current fully ignites the fuel-air mixture.
- Superior Shielding: We use high-quality materials to prevent the wire from acting as a broadcast antenna.
- Reliability Under Load: High-performance engines face extreme vibration and thermal loads. Scott wires maintain their hi-inductance qualities even in the harshest racing environments.
Long-Term Protection for Your Build
If you are still experiencing ghosts in the machine, consider documenting your setup. Look at your wire lengths, the distance between your ignition box and data sensors, and the specific frequency bands your radio uses.
In some cases, adding inductors or bypass capacitors to your power lines can provide that final layer of protection. The higher the resistance of the ignition wires, while still permitting reliable engine performance, the lower the EMI. Our Street Performance wires wire sets are your best defense against unwanted electronic interference.
| Scott Performance Wire Sets | ||
|---|---|---|
| Fiberglass-Sleeved | Silicone Sleeved | Non-Sleeved |
| 30 Ohm | 30 Ohm | 30 Ohm |
| 300 Ohm | 300 Ohm | 300 Ohm |
Choose Scott Performance Spark Plug Wires For Optimum Performance
Founded in 1990 by Brian Scott, Scott Performance Wire rapidly emerged as a front runner in the automotive industry, specializing in top-quality spark plug wires that meet the precise needs of engine builders and automotive enthusiasts alike.
So, if you want your engine to run at its peak and minimize the effects of ignition noise, upgrading to a set of 100% American-made Scott Performance wires is the perfect route to ensure peak reliability and power. Get in touch with us today to order yours.