Best Sparking Plugs (Review & Buying Guide) in 2021

March 15, 2021

Sparking plugs are the one car item that provides electric current from the ignition system to the combustion chamber to spark the air-fuel mixture to start your car. The piston thereafter will set moving and deliver power to the drive train. You should always pay attention to spark plugs and replace them every 20-30 thousand miles. 

Things You Need To Know Before Buying Spark Plugs!

Before we get into the materials and gapping and many more specifications of the spark plugs let’s first talk about the spark plugs themselves. As a car enthusiast, you need to know all aspects of the spark plugs and make the best choice for your car. The spark plugs are not a car mod and will definitely not increase your horsepower. But nonetheless, they are a necessity for your car to keep it running, and to keep it running most efficiently. But different cars need different spark plugs to run at the best engine efficiency and not lose power. 

When it comes to replacing the spark plugs you will be better off replacing them with the OEM sparking plugs recommended in your owner’s manual. That is what the manufacturers recommend and they do put a lot of testing into their tests in order for the cars to run many miles for many years.

Depending on what you are using the car for you should also determine what spark plugs to buy. Turbocharger engines and naturally aspirated engines do not use the same type of spark plugs. 

Spark Plug Specifications

Installing the wrong sparking plugs in your car will not blow up the engine but it will run poorly for sure. Before you make any purchase make sure to read the spark plug specifications and be more familiar with these terms when shopping.

1. Gap

The gap is the distance between the ground electrode and the core. In some instances, you will need to adjust the gapping of the spark plugs to a certain value for best performance. You can do the gapping fairly easily using a coin gapper. If the gap is set to close there will be a very little spark and the combustion will not be complete.

That will cause a misfire, same would happen with the gap being too further apart as the spark will not ignite because of the big distance. Make sure to read carefully about each spark plug gapping or have the service performed by a professional shop. If you are gapping the spark plugs yourself make sure to be careful as you might break the ground electrode.

2. Core Electrode

The core material is the material the inside of your spark plug is built with. Usually, the spark plugs use copper cores as it is a great conductor of electricity and the cheapest out of all. But there are other materials that you can find with your spark plugs. Platinum is another very popular type of spark plug known for the very long lifespan but not as much electro-conductive as copper.

Since being more scarce to find the platinum spark plugs are more expensive but they last a lot longer. If you ever come across double platinum it means that both the core and ground electrode are platinum-based. Last but not least we have iridium which is the most expensive one you can choose. It is more electro-conductive than platinum, not as much as copper but more long-lasting than copper. 

3. Ground Electrode 

The ground electrode is the L-shaped metallic piece you would often see at the tip of the spark plug. There are many types of ground electrolytes, some being dual ground, some four-ground electrodes, and so on. The most typical one you will see is the single ground electrode and the best performing out of all.

Best Sparking Plugs:

  1. Best Performance: NGK Iridium IX
  2. OEM Spark Plugs: Bosch Platinum
  3. Economy Pack: Bosch Super Copper

Before you get to choose your spark plug of choice you need to make sure you understand the basics of how these components work. As mentioned above the spark plugs will ignite the fuel-air mixture with an electrical spark.

The different materials used in the spark plugs are metallic conductors that work well under high temperatures. That is why you see different types of spark plugs. Iridium spark plugs are the best and last the longest. Platinum spark plugs are used from the many brands as the stock plugs that come with your car and last but not least copper which also makes for the economic spark plugs you can find. 

  • NGK Iridium IX

The NGK iridium spark plugs are the best performance spark plugs because of the material, efficiency, durability and dependability. The Iridium is a very good conductor and the iridium tip ensures high durability and a consistently stable sparking. The NGK Iridium IX is designed with a metal plating superior anti-corrosion and anti-seizing properties.

If the spark plug starts to create corrosion on the plate it will not spark correctly and that’s the reason behind engines running rough and misfiring a lot.  The NGK spark plugs will help in high performance, greater fuel economy and durability. The only downside of using iridium spark plugs is the cost. The average replacement cost for a single iridium spark plug is 13$.  

  • Bosch Platinum

Bosch platinum spark plugs are commonly used from the manufacturers into their cars. These are the stock spark plugs and the best one designed for your car. The platinum firing pin and yttrium enhanced ground electrode provide 2X longer service life compared to standard copper plugs.

The bosch platinum are the best oem spark plugs because they offer long miles with no compromise of efficiency, durability and overall performance. The best thing about these spark plugs are the great price they offer in return for their performance.

These spark plugs provide a reliable spark to generate smooth combustion of the fuel-air mixture. Key features of this spark plug include the fine wire Platinum firing pin for better ignitability and the unique 360* continuous laser weld which fuses corrosion resistant Platinum firing pin to base.

Other great features of this spark plug include the Nickel-plated shell with rolled threads which provide complete anti-seize and corrosion protection. 

  • Bosch X5DC Copper with Nickel Spark Plug

The Bosch X5DC Copper with Nickel Spark Plug is an economy replacement spark plug with great durability and long lifespan. The Bosch copper core spark plugs feature a heavy-duty nickel center electrode for longer lasting service life compared to standard copper plugs. Key features include copper core which provides better heat transfer and a heavy-duty nickel center electrode for longer life. The wire is ultra-fine, and the nickel-plated shell prevents it from seizing. These spark plugs are a great fit for cars that installation might be a little harder and need a lot of components to be removed before replacing. 

What to Consider  When Buying Sparking Plugs?

Above we mentioned the specifications of the spark plugs and what does each mean. Here are a few more steps you need to consider before you make any purchase. First if you are shopping online make sure you filter out results to match the car of your choice. That will bring up a list of spark plugs that are compatible with your car model only.

Best spark plugs you can find are the ones listed at your owner’s manual. You can choose aftermarket spark plugs like denso spark plugs and feel no changes in engine performance.

Secondly you need to make sure you buy the spark plug wires together with the spark plugs as well. This is a combo that plays well together and it is strongly recommended to be replaced at the same time. If you are using a newer car you might not need to buy spark plugs wires but coils.

In simpler terms this is what provides current to your spark plugs. Bad sparking plugs are sometimes caused from bad spark plug wires. Same goes for coils. For V shaped engines make sure to check the manual or ask a professional as you might need to make a purchase of 2 for each cylinder.

Best Sparking Plug FAQ

Q. Do sparking plugs increase horsepower?

A: No, sparking plugs are not performance parts but they will certainly play a huge role in running your engine efficiently and not lose power.

Q. Does a loose spark plug wire cause misfire?

A: Yes, make sure to check the connection of the spark plug wire as it provides current to the spark. If the electrical current is not correctly provided to the spark plug you will have a rough running engine with a lot of misfire.

Q. How do I determine a bad sparking plug?

A: A bad spark plug will definitely misfire or idle badly, but for better measurement take out the spark plugs and inspect it. If the spark plug is dark and dry or has corrosion on the core electrode that is a sign of a bad spark plug.

Q. Are bosch sparking plugs reliable?

A: The bosch spark plugs are mostly used from the manufacturer on brand new cars and highly recommended from many manufacturers.

Q. Are the CR8E Nickel Spark Plug compatible with Mercedes?

A: The CR8E Nickel Spark Plug is commonly used with Japanese cars and bikes. 

Our Top Pick 

My 2005 Mercedes Benz E-240 requires 12 spark plugs. This is a V6 naturally aspirated engine which requires 2 sparks for each cylinder. The spark plug of choice for me was the Bosch Platinum Spark Plugs. I did follow the owner’s manual and I strongly suggest that anyone do.

I installed the new spark plugs with the set of coils at the same time and now I am ready for my next Mercedes-Benz mod.

Final Thoughts 

The best spark plugs for engines which need replacement at a professional shop are the Iridium NGK Sparking Plugs. Despite not being as much electro-conductive as copper they will last much longer. This will be a great spark plug replacement kit and you will have to see your mechanic fewer. 

If your engine-bay is easily accessible then the Bosch Copper Spark Plugs will work the best for you. The economy you will get out of those divided over miles give better bang for the buck compared to all others so we recommend you stick with that.

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