When it comes to an internal combustion engine running, there are four main requirements: air, fuel, spark, and compression. However, once you modify the vehicle, particularly by adding forced induction, the factory components are often not designed to meet the increased demands. This is where the aftermarket comes into play. Specifically concerning spark, there are several compelling reasons why you should opt for coil-on-plug technology for your engine. We interviewed Brian Caruth of Performance Distributors to shed light on coil-on-plug, or coil-per-plug for LS enthusiasts, technology specifically for boosted applications.

What are the advantages of converting to coil-on-plug systems?

Brian Caruth (BC): Tuning and maintenance offer significant advantages. Coil-On-Plug (COP) systems enable more precise ignition timing compared to traditional distributor-based ignition systems. With modern technology, tuning becomes easily achievable through programmers and laptops, allowing for the customization of a timing curve tailored to the requirements of a boosted engine. In contrast, traditional ignition systems often require manual adjustments to timing through the manipulation of mechanical advance components. 

Maintenance is another notable benefit of COP coils. With a coil dedicated to each cylinder, swapping out individual coils is straightforward when necessary. Conversely, traditional distributors feature moving parts that wear over time, along with maintenance-intensive components like caps, rotors, and plug wires requiring regular replacement.

What are the advantages of using coil-on-plug systems over conventional distributors?

BC: The COP ignition system offers several advantages. Firstly, each cylinder in COP has its own dedicated coil, delivering direct voltage to the spark plug. This is in contrast to conventional distributor systems, where the spark is generated from a single coil and then dispersed through the distributor and plug wires. The shorter path of resistance in COP means there is minimal loss of spark energy from the coil to the plug. This is crucial for boosted engines, which require maximum spark energy to operate efficiently under higher cylinder pressure.

Additionally, COP coils boast enhanced reliability compared to conventional distributors. Traditional distributors contain numerous moving parts that are susceptible to failure. In contrast, COP systems eliminate moving parts, thereby reducing the likelihood of spark output loss.

Can improved ignition coils enhance performance?

BC: Indeed, boosted engines endure substantially higher cylinder pressures compared to naturally aspirated counterparts, necessitating a stronger spark for effective ignition of the air/fuel mixture. To prevent spark ‘blowout’ under these elevated pressures, plug gaps must be reduced. However, this reduction can lead to insufficient spark to fully burn the fuel, thereby limiting the engine’s power potential.

This is where our S.O.S. coils shine. Their higher voltage output enables an increased plug gap compared to stock coils. Typically, plug gaps can be widened by an additional .010″ over the recommended gap for boosted engines when using S.O.S. coils.

What impact does the use of COP or performance COP coils have on spark plug gap?

BC: As mentioned earlier, reducing the plug gap is crucial in a boosted engine. Due to higher PSI levels, a boosted engine cannot operate with plug gaps as wide as .045″-.052″, as seen in naturally aspirated engines. Typically, to prevent spark extinction, gaps are narrowed to anywhere from .020″-.030″. However, with performance COP coils like our S.O.S. coils, an increase of .005″-.010″ over the recommended plug gap can be utilized to take advantage of the enhanced voltage output in a boosted application. This maximizes the combustion process, resulting in optimal performance for boosted engines.

Are there specific factors to consider when selecting COP coils for higher boost levels?

BC: Our S.O.S. coils serve as a universal solution for boosted engines. Regardless of whether the engine is subjected to 5 lbs or 8 lbs of boost, our coils reliably deliver the necessary voltage to ignite the fuel mixture.

Boosted Blissfully

There are certain things that can frustrate most racers during a track outing, and ignition breakup and spark failure ranks high on the list. Instead of diagnosing when the time comes, look into a coil on-plug conversion or aftermarket coil-on-plug replacement for your boosted application. Consider it the lynchpin to your performance build that prevents downtime and gives your engine the spark it needs.