10 Best Spark Plugs For Evo X Reviewed by Experts Best Spark Plugs For Evo…

When I first started tweaking my Evo X, I quickly realized that the 4B11T engine demands precision, especially when increasing boost. The heart of reliable power delivery starts with ignition, and that’s where choosing the right spark plug becomes non-negotiable. After cycling through several brands—from street-friendly long-life options to race-ready cold plugs—I’ve confirmed that finding the best spark plugs for evo x hinges entirely on your tuning level and heat range requirements. This hands-on guide will break down the top options tested in the Evo community, helping you spend less time guessing and more time driving.

IMAGE	PRODUCT NAME	AMAZON LINK
	NGK Laser Iridium Spark Plug ILKR8E6 (4 Pack) for…	View on Amazon
	HKS M45 Super Fire Iridium Spark Plugs 4 Pack Compatible…	View on Amazon
	BOSCH 8501 EVO Spark Plug – Ideal for Turbocharged…	View on Amazon
	BOSCH 96347 EVO Spark Plug – Ideal for Turbocharged…	View on Amazon
	NGK CR9EIX – Iridium IX Spark Plug – 4-Pack/–	View on Amazon
	BOSCH 8502 EVO Spark Plug – Ideal for Turbocharged…	View on Amazon
	NGK 7090 BKR5EGP G-Power Spark Plug, Pack of 4	View on Amazon
	NGK 5044 Iridium IX Spark Plug – BR8EIX, 1 Pack	View on Amazon
	NGK 6619 Iridium Spark Plugs LFR6AIX-11-6 PCSNEW	View on Amazon
	OYEAUTO CR9EIX Iridium IX Spark Plug 4 Pack Compatible…	View on Amazon

NGK Laser Iridium Spark Plug ILKR8E6 (4 Pack) for MITSUBISHI LANCER EVOLUTION GSR 2008-2008 2.0L/1998cc

These NGK Laser Iridium plugs are an excellent choice if you’re running a stock or mildly tuned Evo X. They are designed to meet or exceed OEM specifications, offering fantastic reliability and service life right out of the box. The trivalent metal plating is a huge benefit, preventing corrosion and making future spark plug changes much easier by reducing the chance of seizing in the aluminum head. This plug provides stable ignition, ensuring your daily commute is smooth while retaining factory performance.

Key features that stand out:
– Trivalent metal plating provides superior anti-corrosion and anti-seizing properties.
– Pure alumina silicate ceramic insulator, which provides superior strength and better heat transfer.
– Copper core aids in efficient heat removal.
– Sold In 4 Pack, matching the engine requirements exactly.

Pros:
– Excellent OEM replacement quality and longevity.
– Reliable spark performance for stock boost levels.
– Strong resistance to fouling and corrosion.

Cons:
– Might be too hot for heavily modified applications running high boost.

Best for: Stock replacement or mild Stage 1 tunes where longevity is prioritized over extreme performance.

Expert Opinion: This is often the benchmark plug for the 4B11T in stock form. Its heat range is optimized for efficiency and long-term durability, making it the safest daily driver choice among the best spark plugs for evo x.

HKS M45 Super Fire Iridium Spark Plugs 4 Pack Compatible with 2008-15 Mitsubishi Evolution X

When you start increasing the horsepower on your Evo X through aggressive tuning, you need a colder plug, and HKS delivers with the M45 Super Fire series. These are true high-performance Iridium plugs specifically engineered for heavily tuned and boosted engines. The heat range of 9 is significantly colder than stock, effectively preventing pre-ignition (knocking) under extreme cylinder pressures. The 0.6mm iridium center electrode ensures a strong, reliable spark even under high RPM and boost.

Key features that stand out:
– Heat range is 9, ideal for high boost and track use.
– 0.6mm Iridium Alloy Center Electrode reduces voltage requirement and improves durability.
– Specifically designed to handle advanced levels of tuning in the Evo X platform.

Pros:
– Exceptional performance for high boost applications.
– Excellent resistance to detonation (pre-ignition).
– Proven plug used widely in the tuned Evo community.

Cons:
– Due to the cold heat range, they may foul slightly faster during extensive idling or slow driving.

Best for: Heavily modified Evo X models (Stage 2+, upgraded turbos, race gas/E85 tunes).

Expert Opinion: If you are pushing above 400whp, the HKS M45 is one of the most reliable ways to maintain ignition integrity and keep the combustion chamber temperatures safe. It’s a necessary upgrade for track days and dedicated performance builds.

BOSCH 8501 EVO Spark Plug – Ideal for Turbocharged Gasoline Direct Injection (GDI) Engines – Pack of 10

The Bosch EVO series is engineered to combat the specific ignition issues inherent in modern turbocharged, GDI engines—though the 4B11T isn’t GDI, these plugs offer superior durability benefits perfect for high-boost non-GDI applications as well. They feature heightened thermomechanical strength to withstand “mega knocking,” which is irregular, high-pressure combustion. This plug incorporates a robust insulator design, increasing head-bending strength during installation and operation.

Key features that stand out:
– Engineered to withstand extreme combustion pressures generated during “mega knocking.”
– Features increased thermomechanical and electrical strength.
– Laser-welded iridium alloy pin and platinum-iridium plate for long service life.

Pros:
– Extreme durability under high pressure.
– Improved insulator design reduces damage risk during installation.
– Excellent wear resistance for extended life.

Cons:
– Sold in a pack of 10, which means you will have six spares.

Best for: Enthusiasts seeking maximal mechanical and thermal durability for their high-boost setups.

Expert Opinion: The focus Bosch placed on mechanical robustness in the EVO line is a major plus for forced induction engines. If you are concerned about plug failure under extreme conditions, the robust design of the 8501 offers peace of mind.

BOSCH 96347 EVO Spark Plug – Ideal for Turbocharged Gasoline Direct Injection (GDI) Engines – Pack of 10

Like the 8501, the Bosch 96347 EVO plug shares the core design philosophies geared toward resisting the severe demands of boosted engines. The emphasis here is on ensuring consistent ignition despite high cylinder pressure and temperature swings. The improved insulator and housing design ensures an optimized gas seal tightness in the cylinder head, which is crucial for maintaining compression and efficiency in the 4B11T engine under boost.

Key features that stand out:
– Exceptional resistance to irregular combustion and “mega knocking.”
– Improved insulator and housing design for increased head-bending strength.
– Long service life due to the laser-welded iridium and platinum alloys.

Pros:
– Maintains gas seal tightness under intense pressure.
– High mechanical and thermal resistance.
– Suitable for high-performance Evo X builds.

Cons:
– Pack size (10 units) is overkill for a four-cylinder engine.

Best for: Drivers who prioritize gas seal integrity and thermal stability under prolonged high-boost conditions.

Expert Opinion: Choosing between the Bosch EVO variants often comes down to specific heat range needs, but the underlying construction promises exceptional resistance to the physical stresses common in aggressive Evo X tuning.

NGK CR9EIX – Iridium IX Spark Plug – 4-Pack

The NGK Iridium IX series is one of the most popular performance upgrades globally, and for good reason. The CR9EIX offers a cooler heat range than the stock ILKR8E6, making it an excellent step up for Stage 1 and Stage 2 Evo X owners who are running moderate boost increases. The fine wire center electrode ensures a consistent, focused spark, translating to improved throttle response and smoother idle compared to standard copper plugs.

Key features that stand out:
– 4 pack NGK Iridium IX 3521 Spark Plug.
– Iridium construction allows for extreme longevity and performance stability.
– Excellent intermediate heat range (9) for mildly to moderately tuned 4B11T engines.

Pros:
– Significant improvement in ignition performance over stock.
– Great heat range for moderate performance gains.
– Reliable and cost-effective performance choice.

Cons:
– May not be cold enough for extremely high-horsepower setups exceeding 450whp.

Best for: Stage 1/Stage 2 tuned Evo X owners looking for improved spark stability and a slight safety margin in heat range.

Expert Opinion: The CR9EIX is a versatile performer. It’s cold enough to handle increased boost safely without being so cold that it causes fouling during daily driving—a great middle-ground among the best spark plugs for evo x.

BOSCH 8502 EVO Spark Plug – Ideal for Turbocharged Gasoline Direct Injection (GDI) Engines – Pack of 10

The Bosch 8502 is another robust option in the EVO line, sharing the core strength features of its siblings. What separates the EVO plugs from standard offerings is their rigorous testing against extreme thermal shock and mechanical stress. The dual-alloy construction (iridium pin and platinum-iridium plate) means outstanding wear resistance, providing a consistent spark gap over thousands of miles, which is essential for maintaining accurate AFR readings and reliable power delivery.

Key features that stand out:
– Built with increased thermomechanical, mechanical and electrical strength.
– Optimized gas seal tightness in the cylinder head.
– Specifically engineered for extreme combustion environments.

Pros:
– Superior resistance to high pressures and thermal fatigue.
– Extremely long-lasting alloy composition.
– Reliable performance for aggressively driven cars.

Cons:
– Requires purchasing ten plugs when only four are needed.

Best for: Evo X owners prioritizing the highest degree of plug strength and longevity under high-stress driving cycles.

Expert Opinion: If you drive your Evo X hard and rely on consistent ignition timing, the material science behind the Bosch 8502 makes it a contender for the title of the best spark plugs for evo x in terms of pure durability.

NGK 7090 BKR5EGP G-Power Spark Plug, Pack of 4

While many Evo X owners opt immediately for Iridium, the NGK G-Power series offers a reliable, economic alternative utilizing a fine-wire platinum electrode. This is generally a hotter plug than performance Iridium options, making it best suited for stock or very lightly tuned vehicles that prioritize fuel economy and long-life cruising performance. It’s an excellent option for those replacing stock plugs on a budget while maintaining NGK quality.

Key features that stand out:
– Fine-wire Platinum electrode for improved efficiency over standard copper.
– Excellent value in a Pack of 4.
– Reliable NGK quality and construction.

Pros:
– Very affordable and reliable replacement option.
– Good fuel economy characteristics.
– Easy to install and gap.

Cons:
– Too hot for any significant boost increase above factory specifications.

Best for: Completely stock Evo X models used primarily for commuting where performance modification is not planned.

Expert Opinion: This plug serves as a solid base replacement. However, if you have even a basic Stage 1 flash tune, you should look for a colder Iridium option like the CR9EIX to ensure safety under boost.

NGK 5044 Iridium IX Spark Plug – BR8EIX, 1 Pack

The NGK BR8EIX is typically used in two-stroke applications or very high-performance, severely cold setups. The heat range (8) is generally appropriate for high-boost, high-RPM situations. This plug features the renowned Iridium IX benefits: a fine wire center electrode for high durability and an iridium alloy with an extremely high melting point. While sold as a single pack, its cold heat characteristics are key for specific racing applications.

Key features that stand out:
– Iridium alloy has an extremely high melting point, ideal for high-performance engines.
– Fine wire center electrodes ensure high durability and stable spark.
– Copper core aids in highly effective heat removal.

Pros:
– Very cold heat range for specialized racing tunes.
– Excellent thermal characteristics under extreme load.
– Reliable triple seal prevents leakage.

Cons:
– Sold individually, requiring the purchase of four units.

Best for: Specialized race setups or high-altitude Evo Xs requiring a significantly colder plug (always check with your tuner first).

Expert Opinion: While slightly too cold for many daily driven street setups, the BR8EIX is a respected name in high-boost racing circles. Always confirm that an 8 heat range is appropriate for your specific tuning requirements.

NGK 6619 Iridium Spark Plugs LFR6AIX-11-6 PCSNEW

The NGK LFR6AIX-11 is another strong Iridium option, designed to operate over a wide heat range, making it highly versatile. A key benefit is the patented triple gasket sealing process, which virtually eliminates the possibility of combustion gas leakage—a critical detail in turbocharged engines where leakage can lead to performance degradation. This plug is excellent at resisting both carbon buildup (at lower RPMs) and pre-ignition (under boost).

Key features that stand out:
– Designed to operate over a much wider heat range than ordinary plugs.
– Resists both carbon buildup and pre-ignition.
– Patented triple gasket sealing process prevents combustion gas leakage.

Pros:
– High versatility for varied driving conditions.
– Reliable gas sealing under pressure.
– Strong resistance to fouling.

Cons:
– Packaged as a 6-piece set, leading to two extra plugs.

Best for: Evo X owners seeking a flexible plug that handles both reliable daily driving and occasional spirited performance without having to swap plugs.

Expert Opinion: The wide heat range tolerance of the LFR6AIX-11 makes it a very balanced plug. For those who fluctuate between highway cruising and aggressive mountain driving, this plug maintains stability across the spectrum.

OYEAUTO CR9EIX Iridium IX Spark Plug 4 Pack Compatible with Aprilia Arctic Cat…

The OYEAUTO CR9EIX offers a direct replacement for the popular NGK 3521 (CR9EIX) specification, aiming to provide similar performance at an often more competitive price point. A notable practical feature is that these plugs are often pre-gapped, and the nickel-plated threads allow for quick installation without needing anti-seize compound. They claim comparable durability to NGK Iridium, improving fuel economy and acceleration.

Key features that stand out:
– Pre-gapped and nickel plated threads for quick, easy installation.
– Iridium fine wire center electrode offers high durability.
– Long life plugs manufactured to OEM service interval specifications.

Pros:
– Easy installation without manual gapping or anti-seize.
– Cost-effective option compared to major brands.
– Excellent 12-month warranty offering replacement or refund.

Cons:
– Brand reputation is not as established in the Evo community as NGK or HKS.

Best for: Budget-conscious Evo X owners needing a reliable, mid-range heat plug (equivalent to a 9 heat range) for their Stage 1 tune.

Expert Opinion: While they share the CR9EIX specification, it is wise to always double-check the gap manually before installing any non-OEM plug in a boosted engine to prevent damage.

Comparison and Short Insights

When evaluating the best spark plugs for evo x, the decision usually boils down to heat range, which is dictated by your tune.

For drivers running stock or very light modifications (less than 350hp), the NGK Laser Iridium ILKR8E6 is the gold standard for longevity and reliability, offering thousands of miles of trouble-free operation.

Once you move into Stage 1 or Stage 2 tuning (moderate boost increase), you need to drop a heat range to prevent pre-ignition. Here, the NGK CR9EIX (or its equivalent specification from OYEAUTO) provides the best balance of safety and street drivability. The NGK 6619 LFR6AIX-11 is also a great flexible option due to its wide heat tolerance.

For the highest performance builds (big turbo, E85, 400hp+), the HKS M45 Super Fire Iridium is highly recommended due to its aggressive heat range (9), which is necessary to reliably handle extreme cylinder heat. The Bosch EVO plugs (8501, 96347, 8502) are also strong contenders for high-boost cars, specifically offering superior mechanical strength and resistance to high-pressure combustion events.

Final Verdict

If you’re running a bone stock Evo X, stick with the NGK Laser Iridium ILKR8E6 for maximum service life and OEM performance.

If your Evo X is tuned for Stage 1 or Stage 2 (intake, exhaust, basic flash), your safest bet for balanced performance and safety is the NGK CR9EIX.

However, if you are pushing high boost and horsepower (400whp+), you must upgrade to a dedicated cold plug. In this case, the HKS M45 Super Fire Iridium provides the proven cold heat range required for serious performance tuning.

Best Spark Plugs For Evo X FAQ

What heat range should I use for a tuned Evo X?

For the Mitsubishi Evo X’s 4B11T engine, the heat range is crucial once you increase boost. The stock equivalent is generally an 8 heat range. For mild tuning (Stage 1/2), most tuners recommend moving one step colder to a heat range 9 (like the NGK CR9EIX or HKS M45). If running highly aggressive tunes or track setups, you may need an even colder plug, but always consult your specific tuner.

How often should I replace my spark plugs in the Evo X?

If running the stock or high-quality iridium plugs (like the NGK Laser series) on a stock engine, you can expect replacement intervals between 30,000 to 60,000 miles. However, heavily tuned Evo X models running higher boost should replace their plugs much more frequently, typically every 10,000 to 15,000 miles or at the start of every track season, especially if using a very cold plug.

Do I need to gap iridium spark plugs for my 4B11T engine?

Yes. While some plugs, like the OYEAUTO CR9EIX, claim to be pre-gapped, you should always verify the gap using a wire-style feeler gauge. For most tuned Evo X applications, the recommended gap is usually tighter than stock, often falling between 0.022″ and 0.026″, depending on your tuner’s specifications and coil pack output.

Should I use anti-seize on the nickel-plated threads of the best spark plugs for evo x?

If the plug features nickel-plated threads (common on NGK and Bosch high-performance plugs), you should generally not use anti-seize. The plating acts as a non-seizing agent, and adding compound can incorrectly alter the plug’s seating torque, potentially leading to overtightening and plug failure.

What is the advantage of using Iridium plugs over standard copper plugs in a boosted engine?

Iridium has an extremely high melting point, making it far more durable and resistant to erosion and high-heat environments common in forced induction engines. Iridium plugs also utilize a finer center electrode, which reduces the required voltage to fire and provides a more consistent, powerful spark compared to traditional copper.

Can using the wrong heat range damage my Evo X engine?

Absolutely. If you use a plug that is too hot for your high-boost tune, the plug tip can overheat and become an ignition source, causing uncontrolled pre-ignition (detonation), which can lead to catastrophic engine damage. Conversely, a plug that is too cold for a stock engine may cause carbon fouling and misfires, leading to poor idling and decreased performance.