Copper Vs Iridium Spark Plugs (With Pros & Cons)

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When it comes to spark plugs- “Copper vs. Iridium Spark Plugs” is the toughest debate in the automotive parts market. Copper spark plugs are the greatest for gaining speed while driving, whereas Iridium plugs are undisputed in terms of their durability. However, copper plugs are not technologically advanced and need to change frequently therefore, manufacturers are using iridium in modern vehicles to reduce the inconveniences. 

The spark plug is a crucial component of a gasoline engine. It supplies a bolt of electrical lightning from the ignition system to the combustion chamber, where it fires up the air-fuel combination, which causes the piston to move and starts the engine. Every conventional spark plug has a copper core electrode with a nickel alloy coating on top.

Iridium plugs are stronger and tougher than Copper, nonetheless, when it comes to performance, iridium plugs perform lower than its counterpart. However, despite performing better Copper plugs are worse at durability which is their biggest disadvantage. In this writing, we are going to discuss the ‘Copper vs. Iridium’ debate by focusing on the major differences they have.

What are Copper Spark Plugs?

coper spark plugs

The heart of every traditional spark plug is constructed of copper that is sealed with nickel alloy. The difference among spark plugs varies in the spark plug tip, in these plugs the tip is copper-coated. This metal is well-known for its conductivity and unique thermal transfer. 

Copper spark plugs give exceptional power when driving and they have a cold starting. They are typically found in vintage engines. Copper’s biggest disadvantage is that it has a low melting point. It is unable to endure the corrosive conditions in the combustion chamber. These plugs have a range of 20,000 miles.

What are Iridium Spark Plugs?

iridium spark plugs

The spark plug tip in these plugs is heavily coated with Iridium. Metal is one of the strongest metals. It is considered to be six times harder and eight times stronger than Copper and Platinum. The first-ever iridium spark plugs were invented by the NGK company.

Iridium spark plugs are popular for their durability. Once it is installed it can cover up to 100,000 miles. They can endure corrosive and extreme conditions. For this, most of the manufacturers are using iridium spark plugs in modern engines. 

Copper vs. Iridium Spark Plugs: Key Differences

ComparisonCopper Spark PlugIridium Spark Plug
Side ElectrodeBiggerSmaller
ConductivityHigherLower than Copper
Thermal conditionColderHotter
Melting Point1085 °Celsius2446 °Celsius
CompatibilityOlder and turbocharged enginesModern as well as advanced engines
ResistanceNot stronger as Iridium plugsYes 

See also: Bosch Vs Denso Spark Plugs: Which Is Best?

Copper vs. Iridium Spark Plugs: Major Differences

  • Heat range is important in spark plugs. Copper plugs are colder than Iridium plugs. However, plugs from iridium can withstand much more heat than copper, because of its higher melting point. Iridium has approximately 700-degree heat endurance capability.
  • A spark plug consists of two electrodes- centre and side. The centre electrode is made of Copper but the material of the side electrode varies. As the name suggests the side electrode of a Copper plug comprises copper which is not modified and these plugs are unable to reduce carbon fouling.
  • The side electrode of an Iridium spark plug is technologically advanced and modified. They are designed to use less voltage and to increase firing efficiency.
  • Iridium spark plugs might be less conductive than Copper however, they do not wear out quickly.
  • The price of a spark plug is not much. Copper plugs are the cheapest ones for their widespread availability but iridium plugs held a higher price than Copper because of their scarcity. In addition, one iridium spark plug is equivalent to three copper plug changes.

Copper vs. Iridium spark plugs: Pros and Cons


Copper PlugsIridium Plugs
-High conductivity
-Provide power
-Focus spark
-Improve acceleration
-For older engines
-Require less voltage
-Cover 100,000 miles
-Effective fuel-burning
-Smooth Throttle 


Copper PlugsIridium Plugs
-Shorter Lifespan
-Frequent plug replacement
-Need more voltage 
-Less conductivity
-After using Iridium plugs using other plugs become difficult


Do iridium spark plugs make a difference?

The high melting point of iridium ensures that your engine will run more smoothly. With these spark plugs, you’ll never have to change them too frequently because they provide better combustion and longer life.

Are copper spark plugs better?

Copper is the perfect material for spark plugs because it has excellent conductivity and transfer of electricity, heat-wise.

Can I use copper spark plugs instead of iridium?

Copper spark plugs are better than Iridium because they don’t overheat. They also conduct electricity well, which means that the firing action will be more efficient with these types of sparks plugged in place.

Is it worth buying iridium spark plugs?

They are worth buying if you want the best out of your engine. They have a high melting point, which means that they can produce great electrodes while retaining their fine characteristics and excellent longevity; they also give better performance than other types such as platinum or stainless steel spark plugs since there’s no need for frequent changes because these will not wear down quickly.

To sum up

The primary function of a spark plug is to transfer the energy to the engine block so that it can start the vehicle. The plugs vary in three materials- Copper, Platinum, and Iridium. While choosing one the most debated issue is ‘Copper Vs. Iridium’ spark plug. Copper has a higher conductivity rate while Iridium has a higher thermal and longevity range. The plugs that are made of Copper can provide more acceleration to the engine than iridium plugs, whereas, iridium plugs can resist corrosion and foul better than Copper. Therefore, you can see the debate is endless.  

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