Car Ninja
Iridium Spark Plugs

15 Best Spark Plug In The Market To Buy With Reviews (2021)

Iridium spark plugs have been the industry standard for decades and are still going strong. Iridium offers many benefits, but they aren’t suitable for every engine.

They are designed for racing and performance applications. They provide a hotter spark, which is better at igniting the air/fuel mixture in your engine.

This results in quicker starts and improved fuel economy. The plugs also have an extended service life of up to 100,000 miles or one year, whichever comes first.

If you’re looking for a spark plug that will give you the best performance possible with minimal maintenance, then these iridium spark plugs are the best fit. 

To help you find the best iridium spark plugs for your needs, we’ve compiled a list of our top five picks for use in most engines.

NGK Iridium IX Spark Plugs are designed for high-performance vehicles and offer a long life span. It is compatible with various cars, including the BMW 3 Series, Subaru WRX, and Lexus ES.

It comes equipped with ultra-fine electrode wire, which ensures superior fuel efficiency and silky-smooth engine response. It generates an optimal air-fuel mixture that boosts power and torque.


  • Durable and reliable than copper and platinum spark plugs.
  • Delivers high performance and fuel efficiency 
  • Equipped with the superfine electrode wire
  • Only need to be changed after 100k miles


  • The varying size of the spaces inside this spark plug makes it more likely to misfire or produce less power.

2. Bosch Double Iridium OE Replacement Spark Plug

Bosch Double Iridium OE Replacement Spark Plug is an innovative spark plug that provides twice as much iridium metal than other plugs on the market, which means it can withstand higher temperatures and deliver more power with minor wear.

It also has double-sided electrodes that provide better performance by reducing misfires, improving acceleration, and increasing fuel efficiency.

It also comes with a platinum center electrode that resists wear and tears in high-heat conditions. The anti-seize coating on the threads lets you easily install it yourself without stripping any of its parts.


  • Maximize reliability, 
  • Assists in heat control and wear resistance.
  • Equipped with ultra-thin .6 millimeter tip
  • Corrosion-resistant 
  • Equipped with a ribbed insulator that prevents misfires


  • No Con

3. Denso SK20R11 Iridium Spark Plug

The Denso SK20R11 is a spark plug that features an iridium center electrode. This material provides better performance than platinum, and it has a longer life span as well.

It also has a higher melting point, which means it can withstand high temperatures in the engine without compromising its ability to produce sparks.

Plus, it has a ceramic insulator, which provides superior performance in extreme heat and cold conditions. 

This product has been tested extensively by our engineers to ensure it meets or exceeds all OEM specifications.

If you’re looking for a reliable spark plug that will last for years with minimal maintenance, this is the one for you!


  • Longer life span than platinum and copper plugs
  • Equipped with tapered electrodes
  • A slight improvement in fuel economy


  • No Con

4. ACDelco 41-993 Professional Iridium

ACDelco Iridium spark plugs are designed with an iridium center electrode, three times harder than platinum, and resists wear better than other metals.

This means that they last up to four times longer than conventional plugs, saving you money on replacements. It has a built-in suppressor to stop radio frequency interference.

This helps car electronics run smoothly, and it’s also easier on your vehicle battery. These plugs are easy to use as they come pre-gapped from the manufacturer, saving a step for DIYs. 


  • Assist in cold engine startup 
  • Deliver smooth performance and maximum efficiency
  • Amazing idle stability 


  • It is delicate and tends to break easily.

5. Bosch X5DC Copper with Nickel Spark Plug

Bosch X5DC Copper with Nickel Spark Plug is designed for gasoline engines and offers excellent performance at a great price.

It has a copper core, nickel electrode, and platinum ground electrode, which provides long life and high voltage spark discharge for better combustion efficiency.

The plug is made from durable materials that resist fouling by oil and other contaminants, so they’ll last longer than standard plugs while still providing reliable service under all driving conditions.

The wire is superfine, and the nickel-plated shell prevents it from seizing due to friction. You may not see any change in your mileage by installing it, but you may notice an increase in engine power.


  • Highly long-lasting 
  • Doesn’t require a unique gap tool for installation
  • Corrosion-resistant plug 
  • Equipped with super fine wire


  • No change in mileage 

Buying Guide Of Iridium Spark Plugs

Choosing the suitable Iridium Spark Plug for your vehicle can be a daunting task. When you’re looking for new spark plugs, it can be hard to know which ones will work best for your car. That’s why we created this buying guide to help you find the right one for you. Have a look.


The size of the spark plug is determined by its heat range, which dictates how hot it can get before it starts to melt or break down. Iridium Spark Plugs have a higher heat tolerance than conventional plugs, so they last longer and perform better under extreme conditions.

Gap Style 

Iridium Spark Plugs have been designed with a gap style that helps reduce pre-ignition (knocking) by up to 40%. This means you’ll get more horsepower from your vehicle’s engine without sacrificing fuel efficiency or performance. 


Iridium Spark Plugs are designed with user-friendliness in mind. They’re one of the easiest plugs on the market to install, and they come pre-gapped from the factory, so there’s no need for additional adjustments!


Iridium Spark Plugs are the most expensive spark plugs on the market. You might be wondering why they are priced higher than the type of spark plugs.

The answer is simple – Iridium has a higher melting point, which means it can withstand high temperatures better and last longer than other types of metal. It also provides a more robust electrical current for your engine to run smoothly and efficiently. 

Bottom Line 

Iridium Spark Plugs are a type of spark plug designed to produce a more robust and cleaner spark. The benefits of Iridium plugs include improved acceleration, better fuel economy, reduced emissions, and increased horsepower. They will give you all the power you need without sacrificing any gas mileage or engine life.

If you want the best performance out of your vehicle, then it’s time to upgrade your spark plugs with Iridium. The aforementioned types and the detailed buying guide will help you make a rational buying decision. You won’t regret making this investment in yourself or your car.

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