13 Advantages and Disadvantages of an Iridium Spark Plug (2024)

The majority of spark plugs that operate in vehicles today feature a copper core center electrode. This design takes advantage of the excellent conducting rates that copper has with electricity, which is better than any other material type used in this product. It also transfers heat faster. It also comes with a nickel alloy covering to protect it because the copper has such a low melting point.

Consumers have a choice when selecting the material on the tip of the electrode for the spark plug. You can have an iridium or a platinum tip to optimize the unit’s performance.

Iridium is approximately eight times stronger and six times harder than platinum. It comes with a 700° higher melting point, which means it can offer exceptionally fine electrodes while retaining preferred wear characteristics. Those benefits also mean that iridium spark plugs are the most expensive ones on the market, often retailing for up to $15 each.

What Is Iridium?

Iridium is a chemical element that has the atomic number 77. It is known for its hardness, but it can also be quite brittle in its natural state. It is a transition metal that’s related to platinum, so it qualifies in some circles as a precious metal.

It was first discovered in 1803 when there were insoluble impurities found in natural platinum. Smithson Tennant is the primary discoverer of the metal, and he named it after the rainbow because of the diverse colors of the salts.

Iridium is also one of the rarest elements that we can find in the Earth’s crust. That’s why it is such an expensive product when purchasing spark plugs coated with it. There are only two naturally-occurring and stable isotopes that are useful for the manufacturing process.

Is it worth the investment? A review of the iridium spark plug advantages and disadvantages can help you to find out!

List of the Advantages of Iridium Spark Plugs

1. It can improve the acceleration profile of your vehicle.
When you make the switch to iridium spark plugs, then you may notice an immediate improvement to your acceleration profile. This advantage occurs because there is a faster response to your throttle operations. You’ll be able to feel the difference immediately, especially if you have put some miles on your older plugs. They can make a real difference when you live in regions where it is necessary to get up to highway speeds quickly to stay safe.

2. You may experience more engine power with iridium spark plugs.
Iridium spark plugs can improve the performance of your engine with regard to its power. This advantage becomes apparent in situations where you need to climb steep hills or handle challenging driving situations. You will notice that the experience behind the wheel becomes more comfortable with the upgrade, giving you a smoother touring ability and more control as you navigate.

This advantage works exceptionally well when you have a variable transmission equipped to your vehicle. If you use a manual transmission, then you can still experience the benefits when your shifting is appropriate to the road conditions.

3. Your vehicle might start better when you upgrade to these spark plugs.
The ultra-fine center electrodes of iridium spark plugs work hard to ensure that you have the best ignition experience possible. Most drivers noticed an immediate improvement in an engine’s starting characteristics immediately after making this upgrade. Because there is so little dispersion in the position of the spark with this product, your idling also becomes more stable afterward.

Although you won’t want to let your engine idle for an extended time because of the potential for damage, the roughness that can occur with standard plugs tends to disappear when you use iridium instead.

4. Iridium spark plugs can improve your fuel economy.
Upgrading to iridium spark plugs can immediately improve your gas mileage on the highway or in the city. This benefit occurs because you have an improved ignition profile that allows your fuel to burn more efficiently. Although the efficiency rates aren’t exceptionally high, most drivers can experience a 10% to 20% gain over an entire tank of gasoline. If you have a high-mileage rate already, that can result in an extra 4-8 miles per gallon.

How much money could you save each week if you could drive up to 80 more miles per week on a single tank of fuel?

5. You have more options from which to choose with iridium spark plugs.
Because of the added expense that comes with iridium spark plugs, the manufacturers reduce the diameter of the center electrode. You’ll find options available that are as little as .4mm when you go in this direction. The design also offers a finer wire with the overall design, creating a better firing efficiency than what you would receive with similar options.

Because of these advantages, many of today’s automakers require the use of iridium spark plugs or ones in combination with platinum for COP ignition systems. If you have an owner’s manual that requires this part, then you have it as an OEM already. Moving to platinum would be a downgrade that could impact the performance of the engine.

6. It requires less voltage than other designs.
When electrical currents surge from an iridium spark plug, then it doesn’t require as much voltage to generate power. That’s because of the unique design that includes a small electrode. Saving on energy during the start-up phase or while accelerating ensures that you have a reserve in place to manage the driving experience better. You’ll discover less lag happening when you press down on the pedal and fewer delays in the initial startup of the engine.

This advantage can work with the cold-cranking amps of your battery to ensure that you have more power available in the winter months.

7. You receive more durability with iridium spark plugs.
The strength of iridium ensures that you can receive a long-lasting installation when you make this upgrade. Even though different manufacturers produce them, you’ll still receive an average of 50,000 miles before the new units require service. Some drivers can get 80,000 miles or more when making this change.

If you were to settle for copper or platinum spark plugs, then you might receive 50% of the lifespan when compared to iridium. That’s why the cost of this product eventually balances itself out over time.

8. You’ll receive more corrosion resistance with iridium spark plugs.
Iridium is the most corrosion-resistant metal that we currently create, even when it operates in environments as high as 2,000°C. Although melted salt and halogens are corrosive to the solid metal, it still functions exceptionally well in the engine compartment because of these traits. That means you have access to a highly reliable part that supports the overall performance of your vehicle consistently.

List of the Disadvantages of Iridium Spark Plugs

1. The cost of iridium spark plugs is their primary disadvantage.
Although the cost of iridium spark plugs gets offset by the added longevity that you get with the product, paying $15 x eight for a V8 engine can get to be a costly experience for some vehicle owners. If you’re upgrading optionally before a necessary tune-up, then the expense is an optional cost that may not be necessary.

Since cars with smaller engines may not see a performance upgrade, then the $60 you’d spend on iridium plugs doesn’t make sense. You would receive a similar outcome by going with whatever the manufacturer recommends.

2. You may not see an improvement in performance.
Because many manufacturers are already calling for the use of iridium components, you may not see an increase in performance when you install new plugs. Some drivers find that they’re simply replacing the OEM parts when they make this purchase. You’d still receive the minor improvements that come when you get rid of the parts that aged over the years, but it won’t be the massive promises that someone going from copper or platinum would experience. That means you could be paying quite a lot to receive something that doesn’t make itself known.

3. Different layering techniques can create subpar results.
When you see expensive spark plugs at a store or from a supplier, then that generally indicates that there are more layers of the precious metals on the part. The priciest models are usually double- or triple-coated to ensure that you receive a high-quality result. If you purchase the cheapest iridium items that are available, then you might receive subpar results when compared to the possible benefits that get listed.

Some copper spark plugs use different shapes and configurations to produce similar results for a fraction of the cost. Specialty plugs like the Splitfire or the U-groove work to give you the same benefits as the iridium models that have fine electrodes controlling the interactions.

4. Some coatings can be brittle.
Iridium can be hard when it is correctly applied to spark plugs. The manufacturing process can also create brittleness in each layer because of the qualities of this metal. If that outcome occurs, then any bumps or scratches to the part could severely impact the performance of the unit. You’ll want to take extra care during the installation process to ensure that you don’t cause any unintended damage that could create problems with your future engine performance.

5. Dust from iridium spark plugs offers a higher risk of flammability.
Another reason to be careful when handling iridium spark plugs involves the dust you can create when scraping the part against other engine components. The dust from this metal is more susceptible to corrosion and flammability, reducing the benefits that are possible with this approach. Damaged iridium dust is also more susceptible to oxygen corrosion and fluorine contamination at higher temperatures.


It is essential to note that many of the advantages and disadvantages of iridium spark plugs are somewhat subjective. The majority of engines and vehicles almost always benefit from the replacement of a standard product. Whether or not the change impacts your overall performance will depend on several variables.

The vehicles and engines that benefit the most are the ones that have a close iridium spark plug match with a similar overall design. You’re also replacing a standard one with a basic copper plug, and the engine has a significant cylinder capacity. You’ll see better results in a V8 engine with this upgrade when compared to a V4 design.

If there isn’t a close match to your standard spark plug, then it isn’t worth the cost of the investment. Some OEM plugs already have this option to provide you with the best performance level possible.

About the Author
Brandon Miller has a B.A. from the University of Texas at Austin. He is a seasoned writer who has written over one hundred articles, which have been read by over 500,000 people. If you have any comments or concerns about this blog post, then please contact the Green Garage team here.

13 Advantages and Disadvantages of an Iridium Spark Plug (2024)


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