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Iridium Spark Plugs

10 Best Iridium Spark Plugs 2025 in the United States

#1

Winner

10.0 score

NGK LKAR7BIX-11S Iridium IX Spark Plug (93501 Iridium Ix), 4 Pack

NGK LKAR7BIX-11S Iridium IX Spark Plug (93501 Iridium Ix), 4 Pack

NGK

10.0 score

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The NGK LKAR7BIX-11S Iridium IX Spark Plug is tailored for performance enthusiasts, offering several notable benefits. Its 0.6mm laser-welded fine Iridium tip ensures high durability and a steady spark, making it ideal for high-performance engines. The tapered ground electrode helps minimize electrical quenching, leading to better ignition performance.

Customer Highlights

A summary of real customer reviews to highlight what shoppers are saying!
Electrode Design
Iridium IX construction ensures excellent ignition efficiency and longevity, leading to improved engine performance and fuel efficiency.
Thread Size and Reach
The slightly slimmer design requires a specific spark plug socket, but installation is straightforward and hassle-free once you have the right tools.
#2
10.0 score

NGK LKR7DIX-11S Iridium IX Spark Plug (93175 Iridium Ix), 4 Pack

12%OFF

NGK LKR7DIX-11S Iridium IX Spark Plug (93175 Iridium Ix), 4 Pack

NGK

10.0 score

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The NGK LKR7DIX-11S Iridium IX Spark Plug is a strong choice for performance enthusiasts looking for enhanced engine efficiency. One of its standout features is the fine Iridium tip, which measures just 0.6 millimeters and is laser welded. This not only ensures durability but also provides a stable spark for improved throttle response. Additionally, the tapered ground electrode design helps reduce electrical quenching, which can enhance ignition performance further. The spark plug's long insulator and ribbed design also work to prevent flashovers, while its triple gasket seal effectively keeps combustion gases contained.

Customer Highlights

A summary of real customer reviews to highlight what shoppers are saying!
Gap Size
The plugs are excellent and didn't require any gap changes, making installation straightforward and hassle-free.
#3
9.9 score

NGK 6619 Iridium Spark Plugs LFR6AIX-11 - 6 PCSNEW

NGK 6619 Iridium Spark Plugs LFR6AIX-11 - 6 PCSNEW

NGK

9.9 score

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The NGK 6619 Iridium Spark Plugs are a solid choice for car owners looking for reliable performance. One of their standout features is their ability to operate over a wider heat range than standard spark plugs, which means they can perform better in various driving conditions. This versatility is a significant advantage, especially for those who drive in fluctuating temperatures or terrains. Additionally, the iridium core helps resist carbon buildup and pre-ignition, which can lead to longer service life and improved engine efficiency. The patented triple gasket sealing process is another plus, as it effectively prevents combustion gas leakage, ensuring optimal performance and reliability.

Top 10 Best Iridium Spark Plugs 2025 in the United States

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Slide 1

MAS

MAS Set of 8 Ignition Coils Pack&16Pcs Iridium Spark Plugs 4469 Compatible with Dodge Challenger Charger Durango Ram 1500 2500 3500 Replacement For UF504 C1649 UF601 52-2061

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#1

Winner

10.0 score

Slide 1Slide 2

NGK

NGK LKAR7BIX-11S Iridium IX Spark Plug (93501 Iridium Ix), 4 Pack

Electrode Design: 0.6mm laser-welded Iridium tip
Thread Size and Reach: M14 x 1.25

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Chosen by 1346 this week

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Slide 1

MAS

MAS Set of 8 Ignition Coils Pack&16Pcs Iridium Spark Plugs 4469 Compatible with Dodge Challenger Charger Durango Ram 1500 2500 3500 Replacement For UF504 C1649 UF601 52-2061

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#2

10.0 score

Slide 1

NGK

NGK LKR7DIX-11S Iridium IX Spark Plug (93175 Iridium Ix), 4 Pack

Electrode Design: tapered ground electrode

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12% OFF
#3

9.9 score

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NGK

NGK 6619 Iridium Spark Plugs LFR6AIX-11 - 6 PCSNEW

Heat Range: wider range than standard plugs
Electrode Design: iridium core
Thread Size and Reach: 14mm thread, 1.25mm pitch
Resistor or Non-Resistor: resistor

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#4

9.8 score

Slide 1

Newparts

NGK Set of 16 Iridium IX Spark Plugs For Chrysler Dodge Jeep Ram 5.7 6.4 V8

Heat Range: high-performance engines
Electrode Design: superior spark and combustion
Gap Size: pre-set optimal measurement
Thread Size and Reach: compatible with specified engines
Resistor or Non-Resistor: resistor-type

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#5

9.6 score

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NGK

6 New NGK Iridium IX Spark Plugs LFR5AIX-11 # 4469

Electrode Design: fine-wire iridium electrode

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#6

9.4 score

Slide 1

NGK

4 New NGK IRIDIUM IX Spark Plug LTR5IX-11# 4344

Heat Range: fits various motorcycle engines
Electrode Design: better ignitability, stable performance
Gap Size: better ignitability, stable performance
Thread Size and Reach: fits many motorcycle models
Resistor or Non-Resistor: resistor-type

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#7

9.2 score

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Sixity Auto

16 pc NGK Iridium IX Spark Plugs compatible with Ram 1500 5.7L V8 2011-2021

Electrode Design: sharper spark focus
Gap Size: 0.04 Inches

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#8

9.0 score

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Sixity Auto

6 pc Champion Iridium Spark Plugs compatible with Ford F-150 2.7L 3.5L V6 2011-2020

Electrode Design: fine-wire center and v-trimmed ground
Gap Size: 0.8 Millimeters
Resistor or Non-Resistor: Resistor

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#9

8.8 score

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NGK

(8-Pack) NGK Spark Plugs TR5IX (Stock # 7397)

Electrode Design: Iridium
Thread Size and Reach: 14mm

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22% OFF
#10

8.6 score

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Sixity Auto

4 pc DENSO Iridium Long Life Spark Plugs compatible with Toyota Corolla 1.8L L4 2009-2015

Electrode Design: unique design
Gap Size: 0.04 Inches

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Buying Guide for the Best Iridium Spark Plugs

Choosing the right iridium spark plugs for your vehicle is crucial for ensuring optimal engine performance, fuel efficiency, and longevity. Iridium spark plugs are known for their durability and ability to provide a strong, consistent spark, which is essential for the proper combustion of fuel in your engine. When selecting iridium spark plugs, it's important to consider several key specifications to ensure you get the best fit for your vehicle and driving needs.
Heat RangeThe heat range of a spark plug indicates its ability to dissipate heat from the combustion chamber. This is important because a spark plug that is too hot can cause pre-ignition and engine knocking, while one that is too cold can lead to fouling and poor performance. Heat ranges are typically numbered, with lower numbers indicating hotter plugs and higher numbers indicating colder plugs. For everyday driving, a mid-range heat plug is usually sufficient. However, if you drive in extreme conditions or have a high-performance engine, you may need a plug with a different heat range. Always refer to your vehicle's manual or consult with a professional to determine the appropriate heat range for your specific vehicle.
Electrode DesignThe electrode design of a spark plug affects the efficiency and strength of the spark it produces. Iridium spark plugs often feature a fine-wire center electrode, which requires less voltage to produce a strong spark and improves ignition efficiency. Some designs also include multiple ground electrodes or a tapered cut, which can further enhance performance. When choosing an electrode design, consider your vehicle's engine type and performance requirements. For most standard vehicles, a single fine-wire electrode is sufficient. For high-performance or modified engines, you might benefit from a more advanced design.
Gap SizeThe gap size of a spark plug is the distance between the center and ground electrodes. This gap is crucial because it affects the spark plug's ability to ignite the air-fuel mixture in the engine. A properly gapped spark plug ensures efficient combustion and optimal engine performance. Gap sizes are usually specified by the vehicle manufacturer and can vary depending on the engine design. It's important to check and adjust the gap size according to your vehicle's specifications. Using a spark plug gap tool, you can easily measure and set the correct gap. For most vehicles, the gap size is pre-set by the manufacturer, but it's always good to double-check before installation.
Thread Size and ReachThread size and reach refer to the dimensions of the spark plug that determine how it fits into the engine's cylinder head. The thread size is the diameter of the threaded portion, while the reach is the length of the threaded portion that extends into the combustion chamber. These specifications are critical because an incorrect size can lead to poor sealing, misfiring, or even engine damage. Always refer to your vehicle's manual or consult with a professional to ensure you select spark plugs with the correct thread size and reach for your engine.
Resistor or Non-ResistorSpark plugs can be either resistor or non-resistor types. Resistor spark plugs contain an internal resistor that helps reduce electromagnetic interference (EMI) and radio frequency interference (RFI), which can affect electronic components in modern vehicles. Non-resistor spark plugs do not have this feature and are typically used in older vehicles or high-performance engines where EMI and RFI are less of a concern. If you drive a modern vehicle with electronic systems, it's generally recommended to use resistor spark plugs to prevent potential interference issues. For older or specialized engines, non-resistor plugs may be suitable.

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