What is the difference between ruthenium and iridium spark plugs? – Jalopnik

The many types of spark plugs are generally named after precious metals used in the center electrode, the ground electrode, or both. Copper plugs are the most affordable and simplest, while iridium plugs have a longer life and can improve combustion, emissions and fuel economy. In between are platinum spark plugs, which offer a nice balance between cost, durability, longevity and performance. However, iridium beats copper and platinum in corrosion resistance, making it extremely strong and well suited for automotive applications.

The latest innovation in spark plug metals is ruthenium, a rare silver metal that belongs to the platinum family and is also closely related to rhodium, palladium, platinum, osmium and iridium. If any of these rare earth metals sound familiar, that’s because some of them are vital elements of your car engine’s catalytic converter, namely platinum, rhodium and palladium.

Like iridium, ruthenium is an extremely sturdy metal and highly resistant to corrosion. Speaking of which, ruthenium can actually last longer than iridium. The latter can continue to spark efficiently for 100,000 miles or more, but ruthenium has a slight advantage in wear resistance and can last up to 120,000 miles.

Niterra North America (NGK) was among the first to commercially debut ruthenium spark plugs in response to the needs of modern engines. But instead of boasting about ruthenium’s ultra-long lifespan, NGK’s marketing focuses more on ruthenium’s high flammability, a property that allows the air/fuel mixture to burn more completely. This results in faster cold starts, smoother and more stable idling and better throttle response.

The NGK Ruthenium HX DFE (double fine electrode) has a ruthenium center electrode and a platinum ground electrode for low heat engines. In other words, ruthenium DFE is a hot spark plug for low speed, low compression or non-turbo engines. The NGK Ruthenium HX PSPE (Projected Square Platinum Electrode) has the same materials, but the design and orientation of the ground electrode is different, making it ideal for high-compression, high-temperature engines. It also makes the ruthenium PSPE a cold spark plug.

Ruthenium offers more benefits than a more exotic sounding name and better wear resistance. It is more durable than iridium at high temperatures and provides more stable performance under harsh driving conditions. Engines that run on iridium plugs can be upgraded to ruthenium plugs, but you must find the correct part number and know whether your car requires hot or cold spark plugs. Ruthenium spark plugs also have a slight price premium over iridium due to their advanced construction, although the benefits should outweigh the additional cost.