What Is Iridium Spark Plug – A to Z

What Is Iridium Spark Plug

If you take a peek under the hood of a car, you will most likely see a spark plug with a copper core. Copper is used in most spark plug production across the state and pretty much everywhere. After all, copper is a fantastic conductor of electricity. It also transfers heat fast, so they are used in wiring and tubing.

Now fast forward a couple of decades, and you have platinum and Iridium spark plugs hitting the shelves. But what is an iridium spark plug, you might wonder.

Fear not, as we have the answers to all your queries regarding spark plugs and every bit of information related to them.

What is Iridium Spark Plug?

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Most cars and bikes designed for racing comprise iridium spark plugs. The feature that distinguishes iridium spark plugs from other spark plugs is that it comprises a center electrode made from iridium metal tip. Additionally, the centers are about millimeters 0.6.

The central electrode is also made from heat transfer mechanisms of a thermo-edge design. The thermo-edge design keeps the anti-fouling performance super smooth. Iridium spark plugs are in general used to coat the spark plug instead of platinum or copper, which were used traditionally.

Due to the increase in the cost of manufacturing these, the diameter of the center electrode has been reduced. You can find iridium spark plugs with a center electrode diameter of as little as 0.4mm.

About Iridium

For those of you who do not know, Iridium is one of the expensive and rarest elements found on Earth. It is a hard substance and can be pretty brittle in its natural state. Iridium is highly durable and has a high melting point.

Advantages of Using Iridium Spark Plugs

You might wonder why you cannot just get regular spark plugs and start drawing assumed comparisons between iridium spark plugs vs. normal spark plugs.

Therefore, as we move forward, let’s take a look at the benefits of using spark plugs in your vehicle, that way, you will know what you are missing out on.

Better Acceleration

Starting your vehicle becomes better, thanks to the iridium spark plugs. The excellent center electrodes try their most challenging for you to have the ignition experience like no other. Because of the tiny dispersion of the spark, the idling also becomes much more stable.

After you shift to iridium spark plugs, you might start to feel a noticeable improvement in your acceleration. This happens due to the faster response of your throttle operations. You will especially feel this difference if the spark plug you are replacing is very old and has quite some miles to it. 

Improved Fuel Economy

You can also expect to see a noticeable improvement in your vehicle’s fuel economy with spark plugs. Your gas mileage will improve whether you are in the city or on the highway.

This happens because of the improved ignition profile, which allows the fuel to burn much more efficiently. The efficiency rate might not be astronomical, but you can expect to experience a 15% to 20% gain over a full tank of gas, resulting in an extra 5 to 8 miles per gallon.

Durable Element

Iridium as a material is very strong and durable. This results in a long-lasting installation that ensures that you do not have to change them at frequent time intervals.

Different manufacturers produce them differently but expect to receive a mileage of somewhere within 50,000 miles to 80,000 miles without making another plug change. Traditional copper or platinum spark plugs last about half of the iridium spark plug lifespan.

Improved Engine Health

Iridium spark plugs can improve your car engine’s performance in terms of its power. You are much more likely to notice this increase in power when you need to climb steep hills or drive through treacherous and much more demanding roads. Navigating them becomes much more comfortable and smoother.

The corrosion resistance of the Iridium spark plug is the highest that modern technology has to offer, even when the operating environment gets as hot as 2000 degrees. Because of its composition, functionality is well maintained in the engine compartment even though halogens and melted salt are incredibly corrosive to the metal.

Disadvantages of Iridium Spark Plugs

While these iridium spark plugs have their good sides, it certainly has some downsides as well. So, let’s take a look at them.

It Can Be a Bit Expensive

Iridium spark plug price is very high. It is somewhat offset by the increased durability and longevity of the products but still, considering the increase in performance and startup speed; it is still on the pricier side.

The increasing prices are especially noticeable when upgraded on a small engine which may not see a spike in performance after the installation. 

Prone to Flammability

The dust created when the iridium spark plugs scream against other engine components can carry a higher risk of being flammable. Thus, it would be best to be extra careful when handling them. 

Iridium dust is much more prone to flammability end corrosion than other metals. They are also more likely to be susceptible to fluorine contamination and oxygen corrosion at high temperatures.

If you go for a cheaper variant of the Iridium spark plug, the answers are- that the layering technique is very subpar, and you will not get the benefits you were looking for.

However, the spark plug models that use double or triple coating can give the best results even with comparatively higher prices.

Iridium Vs. Platinum Spark Plugs

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Nothing can beat Iridium spark plugs if we are talking solely about performance. However, suppose you do not have a tight budget holding you back. In that case, the comparison between iridium spark plugs vs. platinum spark plugs should not even be a question.


Iridium is about six times as hard as regular platinum. As a result, its strength is incredibly superior to that of platinum. On top of being harder than platinum, iridium spark plugs can last much longer than platinum.

Melting Point

Iridium is estimated to be around 25% more durable than platinum or any other spark plugs. It also has a higher melting point of about 700 degrees than platinum. 


Although they perform better than additional spark plugs, Platinum spark plugs cannot outperform iridium spark plugs. Iridium has a much more efficient lighting air and fuel compression inside the combustion chamber. If we are talking about numbers, iridium spark plugs can easily last between 100,000 to about 120,000 miles. 


Is Iridium the primary material used to make spark plugs?

No. Even though traditionally copper was used to making spark plugs, Iridium and platinum are now leading the market.

What is better, Iridium or Platinum?

If we are talking numbers, Iridium is known to be 8x times more vigorous and 6x times harder than platinum; we hope that answers your query.

How frequently should iridium spark plugs be replaced?

Regular spark plugs should be changed every 30k to 50K miles. Luckily, iridium spark plugs can be changed within 60K to as long as 150K miles.


In short, are iridium spark plugs worth it? I guess it ultimately depends on you. However, the benefits they provide certainly cannot be overlooked. 

We hope this guide provided you with the information you were looking for regarding iridium spark plugs. In addition, we hope you know what is an iridium spark plug and make an informed decision based on all the bits and deets we have given you.

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