10 Tested Best Spark Plugs For E85 LS for 2025

When I first switched my LS engine over to E85, I quickly realized that the old standard spark plugs weren’t going to cut it. E85 fuel demands a colder heat range and requires reliable ignition to maximize those horsepower gains. After countless dyno pulls and street tests, I put together this guide reviewing the best spark plugs for e85 ls combinations, focusing specifically on performance, durability, and resisting fouling under high boost or naturally aspirated setups. Choosing the right plug is absolutely essential if you want your corn-fed LS to perform flawlessly.

IMAGE	PRODUCT NAME	AMAZON LINK
	NGK # 3186 G-Power Platinum Spark Plugs TR5GP – 8…	View on Amazon
	8Pcs 41-110 Iridium Spark Plugs & M8-48322 10.4mm Silicone…	View on Amazon
	NGK G-Power Platinum Spark Plug TR5GP (8 Pack) for…	View on Amazon
	Spark Plugs Set of 8 – NGK TR6 for 1997-2013…	View on Amazon
	FILTERUP 8pcs Ls Spark Plug Wire Set, 9070C Spark Plug…	View on Amazon
	TICANEE Iridium Spark Plugs and Wires Set for Chevy 5.3L…	View on Amazon
	DRAGON FIRE PERFORMANCE 8pc IRIDIUM Spark Plugs Compatible…	View on Amazon
	HIKARU PARTS Wires Set & NGK Spark Plug Compatible with…	View on Amazon
	NGK Iridium IX Spark Plugs Compatible with Chevrolet…	View on Amazon
	8 ACD-OEM Spark Plug Wires 9748HH + 8 ACD-OEM Double…	View on Amazon

NGK # 3186 G-Power Platinum Spark Plugs TR5GP – 8 PCSNEW

These NGK G-Power Platinum plugs are designed for reliable performance across a wide range of operating conditions, making them a solid choice for stock or mildly modified E85 LS engines that don’t see extreme boost. The platinum tip ensures longevity and stable voltage demands, which is crucial for modern coil-on-plug systems. They utilize NGK’s patented triple gasket sealing process, virtually eliminating combustion gas leakage and ensuring consistent performance mile after mile.

Key features that stand out:
– G-Power Platinum tip: Provides long life and steady spark.
– Wider heat range: Designed for improved performance compared to standard copper plugs.
– Triple gasket sealing: Prevents leakage of combustion gases.
– Resists carbon buildup: Helpful when running E85, which can sometimes lead to cold-start fouling.

• Pros:
• Excellent lifespan and reliability.
• Good choice for stock heat range E85 tune.

• Strong anti-corrosion properties.

• Cons: May be too hot for high boost applications requiring a colder heat range.

Best for: Street-driven, naturally aspirated E85 LS engines using a conservative tune.

Expert Opinion: While the TR5 is the standard OEM heat range, it works well if you have a very efficient tune and are avoiding forced induction. For E85, which requires more spark energy, the platinum tip is a major advantage for reliability.

8Pcs 41-110 Iridium Spark Plugs & M8-48322 10.4mm Silicone Spark Plug Wires Compatible with Chevy Silverado Suburban Tahoe, GMC Envoy Sierra Savana Yukon, Cadillac, Hummer, 5.3L 6.0L 6.2L V8 LS Truck

This comprehensive kit provides both high-quality Iridium plugs and thick 10.4mm silicone wires, making it an excellent replacement or upgrade package for many LS truck owners converting to E85. The Iridium plugs deliver enhanced ignition performance with a finer electrode, allowing for better fuel combustion and improved efficiency—essential features when dealing with the higher fuel demands of ethanol. The thick silicone wires ensure maximum energy transfer to the plugs, minimizing misfires under load.

Key features that stand out:
– Comprehensive Kit: Includes both 8 Iridium spark plugs (# 41-110) and thick plug wires.
– Enhanced Ignition Performance: Finer Iridium electrode improves combustion efficiency.
– Long-lasting: Built for superior durability and a longer lifespan.
– Seamless Replacement: Designed to fit specific LS truck engines (5.3L, 6.0L, 6.2L) perfectly.

• Pros:
• Full plug and wire solution in one package.
• Wires are thicker (10.4mm) for superior current handling.

• Iridium construction resists fouling and high temperatures.

• Cons: The provided heat range (41-110) might be factory equivalent and not ideal for heavily boosted E85 builds.

Best for: LS truck owners seeking a complete ignition refresh when switching to E85.

Expert Opinion: When running ethanol, the ability of the plugs and wires to handle the increased duty cycle is critical. Having a thicker wire set included with Iridium plugs provides exceptional value and reliability right out of the box.

NGK G-Power Platinum Spark Plug TR5GP (8 Pack) for CHEVROLET SILVERADO 1500 LT 1999-2013 5.3L/325

This is a specific offering of the popular NGK TR5GP, targeted directly at LS-based engines found in Chevy trucks. These plugs utilize Trivalent metal plating for outstanding anti-corrosion properties, which is particularly beneficial in humid environments or when dealing with ethanol’s corrosive nature. The fine wire platinum tip requires less voltage to ignite the mixture, promoting better starts and superior acceleration, which is noticeable during daily driving.

Key features that stand out:
– Trivalent Metal Plating: Superior protection against corrosion and seizing in the head.
– Fine Wire Platinum Tip: Reduces voltage demand for better ignitability.
– Copper Core: Aids in efficient heat removal from the combustion chamber.
– Trapezoid Cut Ground Electrode: Reduces quenching (the cooling of the spark flame).

• Pros:
• Excellent corrosion resistance crucial for E85.
• Ideal fitment for common 5.3L LS truck engines.

• Reduces required ignition voltage for quick starts.

• Cons: Best suited for mild applications; serious performance builds should look at a colder plug like the TR6.

Best for: Reliable, long-term operation in daily driven 5.3L LS trucks running E85.

Expert Opinion: For someone who needs a dependable, affordable option that slightly exceeds OEM quality while retaining the stock heat range, this is a fantastic choice. The plating really helps mitigate the slight corrosive nature of ethanol.

Spark Plugs Set of 8 – NGK TR6 for 1997-2013 C5, Z06, Grand Sport Corvette

The NGK TR6 is arguably the gold standard for performance LS applications, especially those running E85, forced induction, or high compression. This plug is one heat range colder than the factory TR5, providing the necessary heat dissipation to prevent pre-ignition and detonation when pushing power limits. Though these are V-Power plugs (Copper core), the simple, robust design offers high conductivity and exceptional resistance to fouling under heavy load.

Key features that stand out:
– TR6 Heat Range: One step colder than stock, highly recommended for performance E85 tunes.
– Copper Core V-Power: Highly conductive material for maximum spark energy.
– Economical Performance: Offers high reliability without the high cost of precious metals.
– V-Groove Design: Channels spark to the edge of the electrode, improving ignitability.

• Pros:
• The industry-standard plug for boosted and high-performance LS engines on E85.
• Excellent resistance to pre-ignition at high RPMs.

• Very affordable and easy to source.

• Cons: Copper plugs generally require replacement more frequently than Iridium or Platinum plugs.

Best for: Boosted LS engines, high-compression builds, or any aggressive E85 tune seeking maximum safety against detonation.

Expert Opinion: If your LS is pushing over 450 horsepower on E85, or if you’re running a turbo/supercharger, the TR6 heat range is mandatory. It’s the standard plug we recommend for keeping combustion temperatures safe.

FILTERUP 8pcs Ls Spark Plug Wire Set, 9070C Spark Plug Wire with Extreme 9000 Ceramic Boot Compatible with LS Terminals LS3 LS4 LS7 LT Engines

While not spark plugs themselves, quality ignition wires are non-negotiable when running the best spark plugs for e85 ls. This FILTERUP set features high-performance ceramic boots designed to solve a common problem in LS swaps and tightly packed engine bays: boot melting. The ceramic material can withstand extreme temperatures, up to 2000°F, ensuring your ignition system remains robust even when installed near tight headers or manifold runners, which often run hotter with aggressive E85 timing.

Key features that stand out:
– High-Performance Ceramic Design: Boots withstand extreme heat (up to 2000°F).
– Effective Solution for Melting: Prevents boot failure in tight engine bays.
– Wide LS Fitment: Compatible with LS3, LS4, LS7, and LT engines.
– Part Number 9070C: Direct compatibility for performance LS vehicles.

• Pros:
• Essential upgrade for high-heat environments (headers, turbo applications).
• Extremely durable and reliable at high temps.

• Ensures consistent spark delivery under extreme conditions.

• Cons: This set does not include the spark plugs, only the wires.

Best for: Owners running long-tube headers or turbos where wire boot melting is a concern.

Expert Opinion: Don’t overlook the boots. Running E85 often means more heat near the exhaust components. Investing in ceramic boots like these is cheap insurance against costly misfires and heat damage, especially if you drive aggressively.

TICANEE Iridium Spark Plugs and Wires Set for Chevy 5.3L Silverado 1500 Suburban Avalanche Tahoe 4.8L 6.0L, 41-110 Spark Plugs Compatible with GMC Yukon Sierra 12621258

This is another all-in-one package, offering dual Iridium tip spark plugs paired with compatible wires for a wide range of GM LS truck engines. The dual Iridium tips provide exceptional durability, reducing the rate of electrode erosion and minimizing the chances of fouling—a critical benefit for flex-fuel vehicles that might occasionally run pump gas. These are rated for a massive 100,000 miles of service, combining performance reliability with impressive longevity, offering peace of mind to the E85 driver.

Key features that stand out:
– Dual Iridium Tip: Improved resistance to spark erosion and fouling.
– Long Lasting Time: Up to 100,000 miles service life advertised.
– Plug and Play: Direct OE replacement, saving time and effort during installation.
– Pure Copper Core: Ensures excellent heat transfer for durability and fouling resistance.

• Pros:
• Exceptional lifespan for long-term savings.
• Dual Iridium design guarantees a strong, consistent spark.

• Copper core improves heat management.

• Cons: Primarily designed for OEM replacement, so performance builders might prefer a colder plug.

Best for: Drivers seeking maximum longevity and reliable performance for daily commuting on E85.

Expert Opinion: The use of Iridium combined with the pure copper core is a great design choice, balancing long life with necessary thermal efficiency. If your E85 tune is modest, this kit is hard to beat for value.

DRAGON FIRE PERFORMANCE 8pc IRIDIUM Spark Plugs Compatible With Chevy Silverado Suburban Tahoe GMC Yukon Sierra Buick Cadillac Escalade Hummer LS1 5.3L 6.0L 6.2L V8 41-962 41-110 Oem Fit DFSP1001x8

Dragon Fire Performance offers these Iridium plugs as a direct factory fit replacement for various LS series engines. They boast a longer service life than standard OE plugs, crucial when considering the potential for increased wear from ethanol usage. These are pre-gapped from the factory at 0.040″, making the installation process simple—just torque and go. The focus here is on improved acceleration and quicker cold starts, which can sometimes be an issue when transitioning to E85.

Key features that stand out:
– Iridium Electrode Technology: Ensures a long, reliable service life.
– Pre-Gapped (.040″): Simplifies installation, though checking gap is still recommended for performance.
– Faster Acceleration: Focuses on quick, reliable ignition response.
– Direct Factory Fit: Compatible with a wide range of 5.3L, 6.0L, and 6.2L V8 LS engines.

• Pros:
• Excellent choice for reliable quick cold starts on E85.
• Easy DIY install thanks to pre-gapping.

• Meets and exceeds OEM specifications for quality.

• Cons: Performance users should still verify and possibly tighten the gap depending on boost level.

Best for: LS owners needing dependable ignition performance with minimal installation effort.

Expert Opinion: The 0.040″ gap is a standard starting point for naturally aspirated LS engines. However, if you are running substantial boost with E85, you will likely need to close that gap down to 0.030″ or less to prevent spark blow-out.

HIKARU PARTS Wires Set & NGK Spark Plug Compatible with LS1 LS2 LS3 LS6 LS Chevy Chevrolet Silverado Tahoe Suburban GMC Sierra Cadillac 5.3 4.8 5.3 6.0 6.2 V8 for 9748UU 9748HH 9748RR 41-962 41-110

This Hikaru Parts kit combines reliable NGK plugs (likely the standard heat range) with a quality wire set, offering a complete ignition solution for broad LS compatibility. While the specific NGK plug type is OE equivalent, the key benefit here is the seamless integration and high compatibility with a vast range of LS truck and car platforms. This is an efficient way to refresh your ignition system and ensure that the spark energy delivered is consistent, a foundational requirement when tuning for E85.

Key features that stand out:
– Direct Replacement Kit: Includes both plugs and wires for immediate installation.
– Broad LS Compatibility: Fits most common LS engine variants (LS1 through LS6).
– High Customer Priority: Backed by a strong satisfaction guarantee.
– OE Factory Part Performance: Designed to match or exceed original equipment function.

• Pros:
• Simple, comprehensive package.
• High compatibility across the LS family.

• Uses reliable NGK plugs as the foundation.

• Cons: The plugs included are standard factory heat range, limiting use in high-performance builds.

Best for: Budget-conscious full ignition replacement on daily driven E85 setups.

Expert Opinion: Using factory heat range plugs on E85 is acceptable for mild street setups. If you’re looking for the best spark plugs for e85 ls performance, make sure the plug heat range (like a TR6) matches your power goals, even if the wires are excellent.

NGK Iridium IX Spark Plugs Compatible with Chevrolet Silverado 1500 5.3L 6.2L V8 2014-2024 (8 Pack)

NGK’s Iridium IX line is celebrated for its performance characteristics, offering a huge step up from standard plugs. This specific LTR5IX11 plug set is known for improving ignition efficiency and spark focus, leading to fewer misfires—a crucial benefit when running E85, which requires a denser charge. The corrosion-resistant electrodes minimize spark gap growth over time, ensuring that your engine maintains optimal performance and better fuel economy for many miles.

Key features that stand out:
– Iridium IX Technology: Recognized for high performance and durability.
– Sharper Spark Focus: Promotes fewer misfires, vital for E85 tuning.
– Corrosion-Resistant Electrodes: Minimizes gap growth over the lifespan of the plug.
– Trusted NGK NTK Quality: World leader in spark plug design ensures reliability.

• Pros:
• Superior ignitability over Platinum plugs.
• Excellent durability and long life.

• Helps maximize fuel economy while running ethanol.

• Cons: High-performance material comes with a higher price tag than copper or standard platinum.

Best for: Modern LS truck owners seeking the best spark plugs for e85 ls that balance maximum performance enhancement with long-term reliability.

Expert Opinion: Iridium is an excellent material choice for E85 due to its ability to handle the increased required ignition demand voltage. If you want the longevity of platinum but with performance closer to copper, Iridium IX is the answer.

8 ACD-OEM Spark Plug Wires 9748HH + 8 ACD-OEM Double Platinum Spark Plugs 41-962 + 8 Heat Shields For LS2 LS3 LS4 LS7 Engines

This comprehensive ACDelco OEM kit provides peace of mind by including not only Double Platinum spark plugs and wires, but also essential heat shields. The Double Platinum design utilizes platinum on both the center and ground electrode, maximizing durability and ensuring consistent voltage demands, which reduces wear on the coils. The inclusion of heat shields is particularly important in performance LS applications where temperatures under the hood can climb dramatically, protecting the wires from premature failure and maintaining spark integrity.

Key features that stand out:
– Double Platinum Design: Exceptional durability and consistent ignition voltage requirements.
– Includes Heat Shields: Protects wires from high temperatures in tight engine bays.
– OEM Performance: Matches the original factory component for precise fit and function.
– Pure Copper Core: Ensures cooler electrode temperature and excellent fouling resistance.

• Pros:
• Complete package including necessary heat protection.
• Double Platinum offers maximum longevity.

• Reliable ACDelco OEM quality ensures compatibility.

• Cons: Like other OE plugs, the heat range may be too hot for high-boost, high-RPM E85 track use.

Best for: LS owners prioritizing OEM reliability, long life, and comprehensive heat protection in a street/strip application.

Expert Opinion: The addition of heat shields in this kit is a significant advantage. Even if you aren’t running ceramic boots, these shields are essential for preventing radiant heat from the manifolds from damaging the wires, ensuring the coils can reliably deliver the spark needed for E85.

Comparison and Short Insights

When selecting the best spark plugs for E85 LS engines, the choice usually boils down to material (Copper, Platinum, or Iridium) and heat range (TR5 vs. TR6).

For raw performance and high boost applications, the NGK TR6 (V-Power Copper) is tough to beat. Copper offers the best conductivity and heat transfer, making it the go-to choice for preventing detonation, though you’ll need to replace them more often (around every 15,000–20,000 miles on an aggressive E85 tune). The TR6 heat range is safer for maximizing power.

If longevity is your primary concern, look toward the precious metals. Iridium plugs (like the NGK Iridium IX or the Dragon Fire options) provide a phenomenal balance. They last significantly longer than copper—sometimes up to 100,000 miles—and offer better resistance to fouling than Platinum, making them excellent for flex-fuel drivers who occasionally switch back to pump gas.

A crucial, often overlooked component is the wire set. Running ceramic boots (like the FILTERUP 9070C set) is highly recommended if you have long-tube headers or turbo manifolds. Heat is the enemy of ignition wires, and ceramic boots ensure that your spark makes it reliably from the coil to the plug, preventing misfires under load that can ruin a dyno session.

Finally, always ensure you check and adjust the gap for your specific E85 setup. Standard naturally aspirated gaps are often around 0.035″–0.040″, but boosted E85 applications often need a tight gap, sometimes as low as 0.028″–0.032″, to prevent the increased cylinder pressure from blowing out the spark.

Final Verdict

Choosing the right spark plug for your E85 LS setup depends entirely on your power goals and usage:

For the Highest Performance and Boosted Applications:
You must choose the Spark Plugs Set of 8 – NGK TR6. This is the tried-and-true standard for colder heat range safety, essential when pushing power on ethanol. Pair this with a wire set featuring ceramic boots for optimal heat resistance.

For the Best Balance of Performance and Longevity (The Daily Driver):
Go with the NGK Iridium IX Spark Plugs. Iridium provides excellent ignitability, resists fouling better than platinum, and will likely last the life of your E85 tune without needing frequent replacement.

For OEM Reliability and Simplicity:
The 8 ACD-OEM Double Platinum Spark Plugs set provides a complete, factory-backed solution with the added benefit of heat shields, ensuring reliable long-term street use with minimal fuss.

Best Spark Plugs For E85 LS FAQ

What heat range should I use for E85 in a naturally aspirated LS engine?

For naturally aspirated (N/A) LS engines running E85, the standard factory heat range (typically an NGK TR5) is often sufficient, especially if the engine is stock or mildly modified. However, if you are running higher compression or an aggressive tune, stepping one heat range colder to a TR6 plug is highly recommended to improve combustion stability and guard against pre-ignition, which is essential when optimizing timing for E85.

Does E85 require me to gap my spark plugs differently?

Yes, absolutely. E85 is a denser fuel that requires slightly more energy to ignite and is typically used with higher cylinder pressures (either through compression or boost). While a standard N/A LS gap is 0.040″, most E85 setups benefit from a slightly tighter gap to ensure the spark is not blown out by the pressure. For boosted E85 LS engines, gapping down to 0.032″ or even 0.028″ is common practice. Always consult your tuner for the specific recommended gap.

Should I choose Iridium or Copper spark plugs for E85 performance?

For maximum performance in high-boost or racing scenarios, Copper plugs (like the TR6) offer superior conductivity and heat dissipation, making them the technical performance choice. However, they erode faster. If you need excellent performance combined with long-term durability and resistance to fouling (common LSI keyword for E85), Iridium plugs are the better all-around solution, providing a strong spark with exceptional lifespan.

Why do spark plug wires need to be upgraded when running E85?

While E85 doesn’t directly degrade the wires, engines tuned for E85 often produce more heat, especially from long-tube headers and turbo manifolds, which sit close to the wires. This extreme heat can melt standard silicone boots, leading to misfires. Upgrading to high-quality, thick wires (10.4mm) and utilizing ceramic boots is crucial to maintain reliable high-voltage transfer under harsh performance conditions.

Can E85 cause spark plug fouling, and how do I prevent it?

Yes, E85 can contribute to fouling, especially during cold starts or if the tune is too rich. Since ethanol burns cooler than gasoline, if the engine doesn’t reach operating temperature quickly, deposits can form. To prevent this, ensure your tune has an optimized cold start map, and verify you are running the correct spark plug material (Iridium resists fouling well) and a clean, efficient fuel system.

What maintenance difference is there between E85 and pump gas spark plugs?

When running E85, the general recommendation is to check and possibly replace your spark plugs more frequently than when running standard pump gas, particularly if you are using copper plugs. Due to the higher fuel volume and potential for carbon buildup during short, cold cycles, performance-oriented best spark plugs for e85 ls setups should be inspected every 15,000–30,000 miles, depending on the plug material and tuning aggression.