Ruthenium vs Iridium Spark Plug – How Do They Differ?

Spark plugs are core components of your vehicle ignition system responsible for starting your car. However, there are many types in the market, making it challenging to choose the right one addressing your needs.

Generally, all spark plugs are built with copper, with their electrodes featuring a different material. Their electrode material is basically what differentiates one from another. Two of such electrode materials are ruthenium and iridium.

Prepare for an epic battle between ruthenium and Iridium Spark Plug – two mighty metals. Ruthenium, belonging to the prestigious platinum-group family, and Iridium renowned for its unbeatable corrosion resistance. The choice is yours. Either opt for ruthenium electrodes for a budget-friendly option that sacrifices longevity or go for iridium electrodes that guarantee extended durability but at a higher cost.

If you want to know more about the differences between ruthenium and iridium spark plugs, read on to point out their pros and cons while also stating the differences. But first, let’s see the functions of spark plugs.

ruthenium vs iridium spark plug cost

Functions of spark plugs in ignition system

The spark plugs are vital components of an internal combustion engine. Its primary function is helping to provide the spark needed to ignite the fuel-air mixture in the combustion chamber. It is only when these mixtures are ignited that your vehicle starts.

What is the ruthenium spark plug?

Ruthenium spark plugs are spark plugs whose electrodes are made of ruthenium, a very rare and precious metal in the platinum metal group. And are produced by a company called NGK Spark.

NGK ruthenium spark plugs are high-quality spark plugs developed with NGK ruthenium technology. And are built to provide excellent power and efficiency to a car’s engine. They have some of the features iridium and platinum spark plug lacks, giving them an edge over both plugs under discussion.

Ruthenium is among groups of metals with high melting points and doesn’t disintegrate quickly. They are not only corrosion-resistant but also wear well. These spark plugs have high ignition power, allowing for optimal combustion. This also translates to complete fuel burning, better throttle response, and acceleration.

Ruthenium spark plugs are available in two designs —DFE and PSPE. The double fine electrode(DFE) works well with engines with low heat; hence, it is a good fit for regular cars. Whereas the projected square platinum electrode (PSPE) works well in high-temperature engines, hence a good fit for turbo and supercharged engines.

ruthenium spark plug

Pros of ruthenium spark plug

While ruthenium spark plugs notably offer great performance and efficiency, it is best to weigh the pros and cons of ruthenium spark plugs before deciding whether to buy them. Let’s explore the pros before the cons.

Affordability: Despite its quality, ruthenium spark plugs are inexpensive. So, drivers who want a performance or quality plug without breaking the bank will find this plug useful.

High Performance: Ruthenium spark plugs have high ignitability and ensure complete burning of fuel. All of which translates to better throttle response, cold starts, and smoother idle. It also accounts for better vehicle acceleration.

High gas mileage: Coupled with performance, a ruthenium spark plug can increase fuel efficiency by 20% compared to iridium. Due to its fast cold start, ruthenium plugs produce less emission, invariably helping to reduce fuel consumption.

Withstands high pressure: Ruthenium plugs work perfectly at high temperatures and various driving conditions. Whether you’re a slow or fast driver or tow light to heavy loads, ruthenium plugs will do the job.

Low chance of fouling: Since ruthenium plugs work well under high temperatures, they run hot. This hotness helps burn off dirt and other deposits from the plug’s tip, invariably helping to minimize fouling.

Cons of ruthenium spark plug

The disadvantages of ruthenium spark plugs include:

A bit expensive: While ruthenium plugs are inexpensive, they are a bit costlier compared to the regular spark plugs

Can be unpredictable: Ruthenium plugs, while known to work under high temperatures, can also be unpredictable under such conditions and start acting up.

Wear with higher revs: When used in an engine with higher RPM, it tends to wear faster. Unless you go with lower engine revs, you may want to stay away.

Short life span: Ruthenium spark plugs, no doubt, are very durable. However, they possess a lower life span when compared to conventional iridium spark plugs.

Selective: Ruthenium spark plugs are selective as they don’t work well with certain car engines.

What is an iridium spark plug?

Iridium spark plugs utilize a central electrode made with iridium. This electrode material helps in better electricity conductivity type with better firing efficiency. Ultimately translating to better engine performance, like better acceleration and throttle response.

Iridium spark are corrosion-resistant and very durable, invariably reducing the need for new plugs. Due to their strength, they are a good fit for performance engines like supercharged and turbo engines. The plug features a higher melting point, hence the tendency to withstand high temperatures. And are particularly built for high-end engines.

Iridium plugs are also a product of NGK and produces two types of iridium plugs—OE iridium and iridium IX. OE iridium plugs have dual metals and are categorized as the laser series. They are built to provide maximum durability and for OEM applications. OE iridium with dual precious metals are iridium plugs featuring iridium on the center tip and platinum on the ground electrodes.

IX iridium, on the other hand, features only one metal and is designed as an aftermarket spark plug. Hence, they are an excellent choice for modified engines and are sometimes recommended as replacements for OEM plugs. They are available in different sizes and heat range for both automotive and non-automotive apps.

However, while both promise longevity, they have a different life span. While the OE iridium spark plug averages 80k-100k miles, iridium IX averages 40-50 miles.

Iridium Spark Plug

Pros of iridium spark plugs

The following are the strongholds of iridium plugs:

Durable: Iridium is a tough and durable metal; hence, the plug can last longer than any other spark plug—platinum, ruthenium, copper, etc. Typically, Iridium plugs can last between 100k to 120k miles.

Highly ignitable: It generates a more potent spark, which helps in better combustion and fuel economy. More so, because iridium plugs feature tiny electrodes, they use less power during operation, which also translates to better fuel efficiency.

Low rate of fouling: Iridium is stable and, hence, has lower chances of getting corroded.

Cons of iridium spark plugs

The following are the disadvantages of iridium spark plugs.

Expensive: Iridium plugs are made of iridium tips, a very expensive material that invariably affects the cost. Generally, iridium plugs are costlier than any other spark plugs, with a price range from $18-$100 per plug.

Over graded: Placed side by side with a good platinum plug, both have the same performance. Yet, platinum is available for a lesser price. Hence making it look like the iridium plug is overhyped.

Compel users to opt for the highest: Iridium spark plugs come in various ranges. While the cheapest model uses one layer of iridium in the central electrode, the best model uses three layers. And because those with one layer wear faster, users are forced to opt for the most expensive ones.

Ruthenium vs. iridium spark plug: Differences

The differences between ruthenium and iridium plugs are highlighted below.

Price: Ruthenium spark plugs are cheaper than iridium. While a piece of ruthenium costs around $12, iridium ranges from $18-$100.

Durability: While ruthenium spark plugs are less expensive than iridium, they tend to wear out faster. With a ruthenium spark plug lifespan averaging 100k miles, iridium lasts up to 120k miles.

Working conditions: While both plugs can withstand high temperatures, ruthenium can work under higher temperatures than iridium spark plugs.

Fouling: While both plugs have a low chance of fouling, ruthenium degrades faster than iridium when exposed to harsh elements. Iridium is less likely to corrode because it’s more stable.

Performance and engine type: While ruthenium and iridium plugs offer excellent performance, they are built for different engines. Most ruthenium spark plugs are a great choice for regular engine. At the same time, iridium plugs are built for high-performance engines since they expel better power than conventional spark plugs.

Design: When it comes to looks, iridium comes in only one style, whereas ruthenium is available in two designs—DFE and PSPE. While DFE ruthenium plugs work well with regular engines, PSPE are built for high-performance engines like turbo and supercharged engines.

Frequently Asked Questions—FAQs

What’s better than iridium spark plugs?

When it comes to quality and performance, other plugs are no near it. Iridium features finely built electrodes, yet still wear excellently. Its electrode material, iridium, is hard and strong, with a high melting point of about 700°c. Hence, it can chest many explosions before wearing out. The only downside will be the price.

Is ruthenium better than iridium?

Ruthenium vs. iridium spark plugs, which is better? Both metals no doubt are good as both are durable, anti-corrosive, and provide good fuel economy. However, they have features that make them surpass each other.

For example, while ruthenium is known to wear faster than iridium, ruthenium can withstand higher temperatures than iridium due to its higher melting point.  For those still asking, are iridium spark plugs better?

It could be better in build and quality, but that doesn’t mean it’s the right choice for your engine. Imagine buying an expensive plug that isn’t even compatible with your vehicle.

How long does the ruthenium spark plug last?

Ruthenium spark plugs can last an average of 100k miles. However, NGK attests that their new ruthenium Hx spark plugs can last even longer, up to 200k miles. The NGK ruthenium hx review by customers has further buttressed what NGK said. Reviews don’t lie.

However, whether it gets to this distance depends on maintenance and method of use. For example, the Ruthenium DFE does well with regular engines; using it for high-performance engines may cause it to wear fast. If you like ruthenium spark plugs yet own one of these high-end engines, it better you opt for their high-performance plug—PSPE.

Why is ruthenium so valuable?

Ruthenium is valuable because of its rareness. Ruthenium is a rare metal and is available in relatively low amounts. However, despite its rareness, it is one of the most used metals, both commercially and otherwise.

It is used in solar cells, helping to turn light energy into electric energy. It also comes as a hardener for palladium and platinum. In some jewelry, ruthenium is used as an alloy with platinum.

Are ruthenium spark plugs pre-gapped?

Yes! Ruthenium plugs come pre-gapped. So you won’t need to pre-gap it before use.

Are ruthenium spark plugs worth it?

Ruthenium spark plugs sure have their flaws, but they are worth it. These spark plugs are quite affordable, yet with immersive performance. They resist high temperatures, making them function well under extreme temperatures.

They also have high ignitability, which accounts for better engine performance. However, only use them for the engines they are designed for. Remember, while DFE is made for regular engines, PSPE are recommended for high-performance engines.

What type of spark plug is the best?

When comparing side-by-side Ruthenium vs. iridium spark plugs, you could hardly tell which is better since both have their highs and lows and are only suitable for certain engines.  However, there are other plugs like platinum, copper, etc., all with distinct characteristics.

In comparing platinum vs. iridium vs. ruthenium spark plugs, iridium is the strongest, most resistant to corrosion and most durable, though expensive. However, each of them is built for specific vehicles. So, while Iridium could be a better option in terms of build and performance, it may not be the best for your specific application.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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