The Toyota 86/Subaru BRZ chassis has earned a well-deserved reputation for delivering an engaging, analog driving experience. At the heart of this platform lies the FA20 engine, a horizontally opposed four-cylinder that balances efficiency with a strong appetite for revs. The FA20 arrives from the factory with a coil-on-plug (COP) ignition system, a technology that eliminates traditional spark plug wires and places an individual coil directly atop each spark plug. While this design is inherently superior to older distributor or wasted-spark setups, the specific implementation on the FA20 has distinct limitations that become exposed when higher power outputs, aggressive fuels, or sustained track use are introduced. Upgrading to a high-energy coil-on-plug ignition system is not merely a perfunctory modification; it is often a prerequisite for extracting reliable, repeatable performance from a modified FA20. This article moves beyond general theory to examine the real-world results, technical integration, and performance validation of upgrading to a high-performance COP system on the Toyota 86.

The Limitations of the FA20’s Factory Ignition Architecture

To understand the value of an upgrade, one must first recognize the bottlenecks inherent in the stock FA20 ignition components. The engine utilizes specific pencil-style coils manufactured by Denso. For a naturally aspirated engine operating on standard pump fuel, these coils generate sufficient spark energy to reliably ignite the air/fuel mixture. However, they are engineered to a cost and efficiency target, balancing performance against longevity and mass-production constraints.

Spark Blowout Under High Cylinder Pressure

The most common failure point of the stock ignition system occurs when forced induction or high-compression builds are implemented. As cylinder pressure increases, the density of the air/fuel charge rises, requiring a higher voltage (measured in kilovolts) to bridge the spark plug gap. This phenomenon, known as ionization or dielectric breakdown, demands significantly more energy from the ignition coil. The stock FA20 coils have a limited secondary voltage ceiling. When cylinder pressure exceeds a certain threshold, the spark can be physically blown out or the voltage required to jump the gap simply exceeds the coil's capacity. This results in momentary misfires, which are often undetectable to the driver but are clearly visible on a dyno wideband or datalogger as a lean spike or loss of torque. Upgrading to a high-energy COP system with a higher saturation ceiling and faster rise time addresses this fundamental physical limitation.

Dwell Time Asymmetry and Heat Soak

The factory Engine Control Unit (ECU) manages the dwell time, or the time the coil spends saturating with current before firing. The stock dwell tables in the FA20 are calibrated specifically for the stock coils. While the factory ECU does a commendable job, it prioritizes emissions and fuel economy. In a high-RPM, high-load scenario, the stock coils can struggle to fully saturate before the next firing event. Furthermore, the physical location of the coil packs directly over the cylinder head makes them susceptible to heat soak. As under-hood and cylinder head temperatures rise, the electrical resistance within the coil windings increases, further reducing spark energy. High-performance coils are often designed with better thermal dissipation characteristics and lower internal resistance, allowing them to maintain consistent output even in punishing thermal conditions.

Defining a High-Performance COP System

An upgrade is not simply a new set of factory replacement coils. The aftermarket has developed several distinct paths for improving ignition energy on the FA20 platform. Understanding the differences between these systems is critical for making a sound purchasing decision.

OEM+ Direct Replacement Coils

The most accessible upgrade path involves replacing the stock Denso coils with a high-performance variant designed to drop into the factory location without wiring modifications. Examples include coils from OKADA Projects or Brisk Racing. These coils integrate a built-in CDI (Capacitive Discharge Ignition) module or utilize a more advanced core material to boost output voltage and energy (measured in millijoules). Installation is straightforward: remove the old coils, install the new ones. However, these kits come with a significant premium, and their real-world gains on a naturally aspirated engine running pump gas are often marginal. Their true value is realized in applications where the stock dwell table can be slightly adjusted to take advantage of the faster saturation times.

Standalone COP Conversion Kits (CDI + External Coils)

For serious builds, the most robust solution involves ditching the factory coil architecture entirely and installing an external CDI box paired with high-current coils. Systems like those from M&W Ignition or custom implementations of coils from the Nissan R35 GT-R, GM LS-series, or Honda K20 have become popular in the Subaru/Toyota community. These systems use a dedicated ignition controller or are integrated directly into a standalone ECU (like a Motec, Haltech, or Link). The external CDI box separates the coil charging from the ECU, allowing for massive spark energy (often exceeding 100mJ) and extremely fast rise times. This practically eliminates the possibility of spark blowout, even on highly boosted, high-compression, or ethanol-fueled engines. The trade-off is significant installation complexity, requiring custom wiring harnesses, bracket fabrication, and meticulous tuning.

Real-World Performance Validation and Dyno Results

Moving beyond marketing claims, the real-world results of upgrading the COP system on the Toyota 86 can be correlated with specific, measurable improvements in engine performance and reliability.

Combustion Stability and Knock Resistance

The single most important benefit reported by tuners and owners is a marked improvement in combustion stability. On a chassis dyno, this manifests as an extremely smooth power curve with significantly less standard deviation in torque output across multiple pulls. On an engine running an upgraded COP system, the knock sensors register fewer correction events. This is because the high-energy spark ensures a robust, consistent flame kernel initiation. A more consistent burn allows the tuner to advance ignition timing closer to the Maximum Brake Torque (MBT) threshold without triggering knock. While this does not directly "create" horsepower on pump gas, it allows the engine to safely achieve the power it was already capable of, and it often permits a slight increase in ignition timing, yielding a 5-10 whp gain on an already optimized naturally aspirated tune. On a forced induction engine running E85, the gains are more dramatic, allowing for cleaner combustion at higher boost levels.

Throttle Response and Transient Behavior

Drivers subjectively but consistently report a crisper throttle response, particularly during part-throttle transitions and gear changes. The engineering reasoning is sound: a high-energy spark provides a more reliable ignition event under the rapidly changing air/fuel ratios that occur during transients. The engine does not stumble or hesitate as it re-oxygenates the sensors and adjusts fuel trim, leading to a feeling of immediate, linear power delivery. This is especially noticeable in motorsport applications where precise throttle modulation is required for car control.

High-RPM Power Retention

Dyno charts from upgraded FA20 engines often show a characteristic improvement in the top-end power band. The stock coils tend to lose saturation efficiency as RPMs climb, leading to a natural torque drop-off. High-energy COP systems maintain their discharge voltage and duration regardless of engine speed. This allows the engine to sustain torque beyond its traditional peak, effectively widening the power band. For road racing and time attack, this means fewer shifts and maintaining a higher average speed through the corners. Testimonials from the FT86 Club and Subaru performance communities frequently cite a reduction in high-rpm misfire counts after switching to a dedicated COP system.

Installation, Wiring, and Dwell Tuning Requirements

Successfully upgrading to a high-performance COP system depends entirely on the quality of the installation and calibration. This is not an area where shortcuts lead to positive outcomes.

Physical Installation and Harness Integration

For OEM+ replacement coils, the installation is a direct plug-and-play process. The owner must ensure the spark plug tube seals are in good condition to prevent oil ingress. For standalone conversions, the process is far more involved. The factory ECU must be bypassed or re-purposed. Typically, the installer uses an adapter harness that connects to the stock ECU pins but routes the primary ignition control signal to the external CDI unit. The high-current output from the CDI box is then distributed to the individual coils. Proper grounding and shielding are essential to prevent electrical noise from interfering with the sensitive MAF or knock sensor circuits. Connector selection is critical; using waterproof Deutsch or AMP connectors ensures long-term reliability in the harsh engine bay environment.

Mastering Dwell Time Management

This is the most technically critical part of the conversion. Dwell time is the duration the ignition control module allows current to flow through the primary windings of the coil. Too little dwell, and the coil does not reach full saturation, resulting in a weak spark. Too much dwell, and the coil overheats, leading to premature failure of both the coil and the ECU driver. When changing to a different coil part (e.g., an R35 GT-R coil), the stock dwell table programmed in the FA20 ECU via EcuTEK or BRZEdit becomes invalid. The tuner must input the manufacturer-recommended dwell values for the specific coil being used. Many high-performance coils require a constant dwell (e.g., 4.5ms) across the entire RPM range, which is different from the factory's ramped dwell strategy. Failure to correctly configure dwell is the number one cause of issues post-installation. Community-driven guides on FT86Club provide a starting point, but professional tuning on a dyno is highly recommended.

Spark Plug Gap Adjustments

An upgraded ignition system provides the opportunity to optimize the spark plug gap. With higher spark energy available, a larger gap can be run on naturally aspirated engines to increase the spark kernel size and improve lean burn characteristics. On forced induction engines, a high-energy system allows for a tighter gap than what would be required with a weak coil, reducing the risk of misfire. However, the gap must be chosen carefully based on boost pressure and fuel type. Using the increased energy to run a slightly larger gap than stock can yield noticeable improvements in idle quality and low-load combustion. It is standard practice to perform a step-by-step gap test on the dyno, checking for misfires and knock at increasing gap sizes to find the optimal setting for the specific fuel and boost level.

Addressing Common Misconceptions About COP Upgrades

Several myths persist regarding ignition upgrades. A clear understanding helps set realistic expectations.

Myth: "An ignition upgrade is the first step to big power."
While a robust ignition is essential for high horsepower, it is a supporting modification. On a stock Toyota 86, a COP upgrade alone will not unlock 20 horsepower. The stock system is adequate for the factory power level. This modification becomes mandatory as an enabling technology when boost is raised or ethanol is used.

Myth: "All COP systems are the same."
There is a vast difference between a high-quality IGN-1A kit and a generic set of coils. The rise time, energy output at varying RPM, and thermal stability differ drastically. A poorly matched coil can actually perform worse than stock. Researching the specific coil's saturation curve and ensuring it matches the ECU's capabilities is essential.

Myth: "More spark energy always means more power."
More spark energy means more reliable ignition. It prevents misfires. If the engine was not misfiring before, increasing spark energy will not increase peak power. It will, however, allow for a safer tune and prevent power loss from knock retardation, particularly in hot ambient conditions.

Weighing the Investment: When Is It Worth It?

The decision to upgrade to a high-performance COP system on a Toyota 86 comes down to build goals and budget. For a street-driven car on a standard naturally aspirated tune with 93 octane fuel, the investment is difficult to justify purely on a power-per-dollar basis. The best upgrade for a stock-ish car is ensuring the existing ignition system is in perfect health—new plugs, verified coil condition, and a good battery.

The value proposition changes dramatically for specific use cases:

  • Forced Induction: If you are supercharging or turbocharging, an upgraded COP system should be budgeted for from day one. The stock coils will eventually be a limiting factor.
  • Ethanol (E85) Tuning: Ethanol has a higher latent heat of vaporization and requires more ignition energy to ignite reliably. Upgraded coils are highly recommended for any E85 build.
  • High-RPM Road Racing: If the engine is built to rev past 7500 RPM, the stock dwell management may not provide sufficient energy. A high-energy CDI or COP system ensures power is maintained to the redline.
  • Reliability Focus: For owners who value consistency over peak numbers, the increased safety margin against misfire and knock makes an upgraded COP system a sound investment in engine longevity.

The aftermarket has responded with a range of robust solutions. Companies like FC Tuning have developed plug-and-play kits that integrate high-output coils with pre-made wiring harnesses and ECU calibration support, simplifying the conversion for the DIY enthusiast. These kits often include the necessary dwell tuning files or a basemap that can be loaded using a tuning suite like EcuTEK.

Conclusion: Results Dictated by Preparation

Upgrading to a coil-on-plug ignition system on the Toyota 86 is a technical modification that delivers its best results when the rest of the engine package is optimized to take advantage of it. The real-world results—smoother power delivery, enhanced knock suppression, improved high-rpm reliability, and crisper throttle response—are directly proportional to the quality of the tuning and installation that accompanies the hardware. For the naturally aspirated daily driver, it is a premium upgrade. For the development of a high-horsepower, forced induction, or ethanol-powered track car, it is an essential foundation. The stock FA20 ignition is a capable system, but it has a ceiling. A properly selected and tuned high-performance COP system destroys that ceiling, providing the consistency and reliability required to push the FA20 to its full potential. Before making a purchase, consult with a knowledgeable tuner and research the specific hardware compatibility with your vehicle's ECU to ensure the investment yields the expected performance and reliability dividends.