Oil Filled Ignition Coils vs. OEM Coils: Which Provides Better Performance?

by:Haiyan     2023-10-24

Oil Filled Ignition Coils vs. OEM Coils: Which Provides Better Performance?


The ignition system is a critical component of any internal combustion engine. It plays a crucial role in starting the engine, generating power, and ensuring smooth operation. Ignition coils are an integral part of this system, responsible for converting low voltage into high voltage, which then ignites the fuel-air mixture in the combustion chamber. When it comes to choosing the right ignition coils, car enthusiasts are often torn between oil filled ignition coils and OEM (Original Equipment Manufacturer) coils. In this article, we will compare the two and determine which one provides better performance for your vehicle.

1. The Basics of Ignition Coils

Before delving into the comparison, let's first understand the basics of ignition coils. Ignition coils are electrical transformers that consist of two windings - primary and secondary. The primary winding is connected to the battery and produces low voltage. When a current flows through it, it creates a magnetic field. This magnetic field then collapses, inducing a high voltage in the secondary winding. The high voltage generated is supplied to the spark plugs, leading to the ignition of the fuel-air mixture.

2. Oil Filled Ignition Coils

Oil filled ignition coils, also known as epoxy-filled ignition coils, are designed with epoxy resin inside the coil case. This oil-like substance surrounds the windings and provides electrical insulation and improved heat dissipation. The oil-filled design offers several advantages, such as enhanced durability, protection against vibrations and shocks, and resistance to moisture and dirt. These coils are often aftermarket alternatives, providing an upgrade over the standard OEM coils.

3. OEM (Original Equipment Manufacturer) Coils

OEM coils are the ignition coils that come with your vehicle when it rolls out of the factory. They are specifically designed and manufactured by the car's original equipment manufacturer. OEM coils are developed to meet the exact specifications and requirements of the vehicle, ensuring optimal performance and reliability. These coils are often praised for their compatibility and seamless integration with the engine's electrical system.

4. Performance Comparison

When it comes to performance, both oil filled ignition coils and OEM coils have their strengths and limitations. Let's evaluate them based on several key factors:

i. Durability and Longevity

Oil filled ignition coils, with their epoxy-filled construction, offer superior durability compared to OEM coils. The epoxy resin provides excellent protection against external elements, such as moisture, dirt, and vibrations, which can often lead to premature coil failure. On the contrary, while OEM coils are generally reliable, they might not withstand extreme conditions or rough usage as effectively as oil filled coils.

ii. Heat Dissipation

Heat dissipation is a critical factor in the performance of ignition coils. Excessive heat can cause the coil to overheat and lead to performance issues or even failure. Oil filled ignition coils excel in heat dissipation due to the epoxy resin surrounding the windings. The oil-like substance effectively dissipates heat, helping to keep the coil at an optimal operating temperature. OEM coils, on the other hand, may not have the same level of heat dissipation as oil filled coils, which can be a concern in high-performance engines or hot climates.

iii. Electrical Insulation

Proper electrical insulation is essential to prevent any current leakage that could disrupt the ignition process. Oil filled ignition coils offer excellent electrical insulation due to the epoxy resin encapsulation. The resin acts as a barrier, preventing any stray currents or voltage leaks. OEM coils are also designed with adequate insulation but may have slight variations depending on the manufacturer.

iv. Performance in Extreme Conditions

In demanding driving conditions, such as racing or towing heavy loads, the ignition system is put under significant stress. Oil filled ignition coils have proven to perform exceptionally well in these extreme conditions. The enhanced durability and heat dissipation capabilities contribute to maintaining consistent performance even under heavy load. OEM coils, while often reliable, might not exhibit the same level of performance and resilience in such situations.

v. Compatibility and Cost

One advantage of OEM coils is their direct compatibility with the vehicle's electrical system. Since they are specifically designed for the make and model, there are no compatibility issues, and installation is usually straightforward. However, OEM coils can be more expensive compared to oil filled ignition coils, which are often aftermarket alternatives. If you are on a budget or looking for an upgrade option, oil filled coils can provide a cost-effective solution.


In the debate between oil filled ignition coils and OEM coils, there is no definitive answer as to which provides better performance. It ultimately depends on your specific needs and priorities. If durability, heat dissipation, and performance in extreme conditions are your main concerns, oil filled ignition coils might be the better choice. On the other hand, if seamless compatibility and adherence to the original design are crucial, OEM coils could be the ideal option. Consider your vehicle usage, budget, and long-term goals to make an informed decision. Remember, the ignition system is a vital component for engine performance, so choose wisely for optimal results.

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