Iridium Spark Plugs: (Pros & Cons and Our Expert’s Opinion)

It is no secret that we all want to ensure our vehicles are equipped with the best components to experience optimum performance. Believe it or not, spark plugs play a prominent role in the overall function of your vehicle’s engine performance.

Using iridium spark plugs helps your vehicle’s engine run smoother, accelerate faster, produce more power, and experience better fuel efficiency than competing spark plug materials.

Types of Iridium Spark Plugs

All iridium spark plugs are the same, right? Wrong. Iridium spark plugs, as a whole, have the higher functioning capability as opposed to platinum and other types of spark plugs; but all iridium spark plugs are not the same. Here are the varying types of iridium spark plugs:

1) Double Iridium

Double iridium spark plugs contain laser welded iridium on the center and ground electrodes. This makes them extra durable to harsh conditions and is prominent in industrial combustion engines.

Double iridium spark plugs boast better overall performance, longevity, durability, and lower voltage than other types of spark plugs.

Much like double-platinum spark plugs, double-iridium spark plugs contain two rare-metal discs that increase durability and performance.

This increased durability makes them four times stronger than the copper alternative and provides a platform for your vehicle to perform at higher speeds for longer.

2) NGK Iridium IX

NGK Iridium IX spark plug is the preferred spark plug for modified engines as they offer superior performance and are a compatible replacement for OEM spark plugs.

They also come in various sizes for optimal vehicle compatibility and varying head ranges to ensure optimum performance.

3) Laser Iridium

Laser Iridium spark plugs are the superior spark plug option in the iridium category. The laser technology ensures higher ignitability rates and a longer lifespan.

The laser iridium spark plug has a tip with the smallest diameter creating a slower wear rate, lower emission, and improved fuel economy.

What Is So Special about Iridium Spark Plugs?

As with any other product, iridium spark plugs have several disadvantages. While disadvantages are present, the advantages of using an iridium spark plug over the alternative far outweigh the disadvantages in most instances.

Improved Fuel EfficiencyCost
Improved AccelerationBrittle Coating
Greater Engine PowerFlammable Dust
Cleaner Vehicle Start 
Extensive Durability 

Advantages of Iridium Spark Plugs

The advantages of iridium spark plugs vs. copper and platinum seem to be endless. With so many aspects that outperform the competitors, it’s tough to select the best advantages. Needless to say, here are some of the top benefits of iridium spark plugs:

1) Improve Fuel Efficiency

The higher ignition profile ensures the fuel you burn is burned efficiently. While this improvement is not incredibly noticeable, you will notice increased fuel efficiency when using iridium spark plugs.

Because gasoline is burned efficiently with iridium spark plugs, they also help provide economic and environmental benefits compared to the competition.

2) Improves Acceleration

If you drive a gasoline-powered vehicle, using iridium spark plugs can improve your acceleration time. This improvement directly results from the speed at which gasoline engines recognize the throttle operation iridium spark plugs produce.

The increased acceleration speeds are highly beneficial for vehicles that need to reach highway speeds with a short distance to cover.

3) Produce Greater Engine Power

Because the durability of iridium spark plugs is so high, they can produce greater engine power. This makes them a suitable spark plug option for off-road vehicles for towing vehicles that need a little more horsepower to get the job done.

4) Cleaner Vehicle Start

If you enjoy a clean engine start, using iridium spark plugs will ensure you receive such a start every time. The cleaner engine start is a direct response to the increased combustion, which results in little dispersion at the position of the spark.

5) Extensive Durability

Iridium spark plugs are eight times stronger than platinum spark plugs. They also have a 700 degree higher melting point and are six times harder. This makes them one of the most durable spark plug options, and they can last around 25% longer than platinum spark plugs.

Disadvantages of Iridium Spark Plugs

While the advantages outweigh the disadvantages, iridium spark plugs have several drawbacks that need pondering before making the switch. Here are the top disadvantages of iridium spark plugs:

1) Cost

The primary disadvantage of iridium spark plugs is the cost. Due to the durability and longevity of the iridium-based spark plugs, they hold a higher price tag than the competition. However, the high-quality and costly iridium is worth the cost as its performance is unmatched by the competition.

2) Brittle Coating

While iridium is a hard material and improves the functionality of the spark plugs tremendously, if not correctly applied, it can become brittle.

To help prevent this brittleness from occurring, it is vital to carefully install the spark plugs to ensure no bumps or scratches hinder the plug’s performance.

3) Flammable Dust

One cautionary measure that must be taken when handling iridium spark plugs is to ensure you don’t scrape the spark plug against other engine components.

If this happens, it can create dust susceptible to oxygen corrosion and fluorine contamination, which produces a fire hazard at higher temperatures.

Who Makes Iridium Spark Plugs?

Because of the rising popularity of iridium spark plugs, most if not all spark plug manufacturers offer an iridium spark plug.

The most popular iridium spark plug manufacturers are NGK, ACDelco, and Bosch. These manufacturers specialize in spark plugs to ensure the end product is precisely what you need for your vehicle to perform at its highest potential.

NGK operates out of Nagoya, Japan, and supplies a variety of products including, ceramics, cutting tools, and much more. Their most popular iridium spark plug is the 6619 Iridium IX Spark Plug.

ACDelco is based in Grand Blanc, MI, and receives ownership from General Motors. Due to the relationship between ACDelco and GM, ACDelco products encourage optimal performance in GM manufactured vehicles. A popular iridium spark plug produced by ACDelco is the 41-993 Professional Iridium Spark Plug.

Bosch is another spark plug brand known for its iridium line of plugs. Headquartered in Stuttgart, Germany, Bosch specializes in household appliances to spark plugs. While the most popular spark plug Bosch produces is a platinum plug, they offer a variety of iridium plugs. 

The best way to find competitive iridium spark plug manufacturers is to search automotive retailer websites for iridium spark plugs and compare brand, pricing, and compatibility.

How Can You Tell if NGK Iridium Spark Plugs Are Fake?

NGK is a well-known spark plug manufacturer that provides a high-quality product to its end users.

When a company becomes known for its product, imposters often try to tag onto the company’s name and sell a cheaper version of the product that the manufacturer produces. This has recently been the case with NGK iridium spark plugs.

The NGK Technical Service Center was made aware of a fake NGK spark plug that did not meet the requirements. This resulted in engine damage to those that purchased these plugs as the center electrodes could not stand the heat and melted.

The melting of the electrodes directly correlates to the fake iridium spark plug not containing any iridium. Therefore, it is weak and does not stand up in the demanding environment as a real iridium spark plug should.

Here are several things to look for when purchasing NGK spark plugs to ensure they are real and not fake:

  1. Inspect the text printed directly on the spark plug. If there are signs of smudging or wear, it is likely a fake. The ink on NGK manufactured iridium spark plugs will not smear as easily as a counterfeit.
  2. Check for a cutting mark. If a cutting mark appears on the spark plug caulking, it may signify that the iridium spark plug is fake. Without the proper equipment, it is tough to mimic the precise cuts.
  3. Take a close look at the hexagon. The hexagon on the mid-section of the spark plug contains a LOT number on a real NGK iridium spark plug. If the hexagon is missing a LOT number or does not contain the proper font, it is not manufactured by NGK.
  4. Cutting marks on the C-groove. Similar to visible cutting marks on the caulking, if there are prominent cutting marks on the C-groove, it is a likely indicator that the spark plug is not up to par. Counterfeit spark plugs typically have these cutting marks.
  5. Compare electrodes. One of the indicators of counterfeit NGK iridium spark plugs is the quality of the electrodes. The shape and color of the electrode will help you determine whether or not it is made of iridium.

For a detailed, step-by-step view of the counterfeit features of the NGK iridium spark plugs, we recommend you watch this video.

Bonus Tips

Due to the durability and longevity that iridium provides to spark plugs, iridium-based spark plugs are the best-selling types of spark plugs. They give users better gas mileage, higher performance ratings, extended reliability, and have a long life span.

Iridium spark plugs are also the most durable spark plug option. They last longer and are better equipped to help your engine run to its fullest potential. Iridium spark plugs are also stronger and more durable than platinum and copper.

Where to Buy Iridium Spark Plugs

Because vehicle manufacturers widely use iridium spark plugs, they are easy to acquire. Iridium spark plugs are sold at most automotive parts retailers including, O’Reilly Automotive, Parts City Auto Parts, and AutoZone.

Iridium spark plugs are also available for purchase from retailers like Walmart, Amazon, and any other business that sells automotive aftermarket parts. For the best results, you can order iridium spark plugs online directly from the manufacturer’s website.

Iridium Spark Plugs FAQs

Do NGK iridium spark plugs increase horsepower?

Yes, NGK iridium spark plugs can increase horsepower. By providing more spark to the firing tip, you combust more fuel, producing more horsepower.

The higher horsepower produced by using NGK iridium spark plugs improves acceleration speeds making it an attractive option for vehicles that need to reach highway speeds quickly.

Are laser iridium spark plugs better?

Laser Iridium spark plugs are known as the premier spark plug. By combining the laser technology with the strength of iridium, laser iridium spark plugs provide precision that other spark plugs cannot match.

How often should iridium spark plugs be changed?

The average lifespan of iridium spark plugs is 60,000-150,000 miles. Changing your spark plugs ultimately comes down to the specific plug and your vehicle. However, it is vital to ensure your iridium spark plugs are changed within the 60,000-150,000-mile range.

Are you supposed to gap iridium spark plugs?

Iridium spark plugs do not require gapping. Due to the pre-gapping process iridium spark plugs encounter when created, no gapping is necessary. If you attempt to gap these plugs and do so improperly, you can cause damage to the spark plug to where it is no longer functional.

Can you mix platinum and iridium spark plugs?

While it is recommended you replace your spark plugs in unison with the same type of plug, you can mix platinum and iridium spark plugs if the heat range is the same.

You will most likely notice the platinum spark plug expiring before the iridium spark plug due to the increased lifespan of iridium spark plugs.

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Author: DJ

Dave Junior is a hands-on automotive technician with experience in performing service, diagnostics, and repairs on domestic and imported vehicles. He enjoys writing and sharing his knowledge far and wide.

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