Best Spark Plugs For E85: Compare 10 Plug Options

#1 · Best Overall

1. NGK LKAR7BIX-11S Iridium IX

• Core Material: Iridium
• Top Material Type: Metal
• Compatible with Vehicle Type: Car, Truck
• Thread Size: M12 x 1.25

Best for: Fine-Tip Iridium Performance Set.

Why it ranks #1: Its fine iridium tip and stated anti-fouling features suit performance-oriented consideration; the listing gives an M12 x 1.25 thread and 0.6 mm gap.

A 0.6 mm laser-welded fine iridium tip is the central feature of NGK’s Iridium IX plug, with the listing connecting it to durability and a stable spark. A tapered ground electrode is also specified to minimize electrical quenching, supporting its performance-focused positioning.

NGK lists several features relevant to ignition and maintenance: the fine iridium tip is tied to a stable spark and durability, while a tapered ground electrode minimizes electrical quenching. A longer insulator nose is intended to prevent fouling, and corrugated insulator ribs prevent flashover; the triple-gasket seal addresses combustion-gas leakage. Four plugs are included, with an M12 x 1.25 thread and 0.6 mm gap. These details aid application matching but do not establish E85-specific compatibility.

Skip it if you need an eight-plug set; NGK TR5GP G-Power Platinum is listed as an eight-piece pack.

Performance-focused buyers may value this four-pack’s fine iridium tip, tapered ground electrode, and insulator features when the M12 x 1.25 thread and 0.6 mm gap match. The supplied facts do not identify a specific E85 application.

Listed on Amazon as: NGK LKAR7BIX-11S Iridium IX Spark Plug (93501 Iridium Ix), 4 Pack

#2 · Best Copper Option

2. NGK TR6 Copper

• Core Material: Copper
• Top Material Type: Nickel
• Compatible with Vehicle Type: Car
• Thread Size: 14

Best for: Corvette Eight-Plug Set.

Why it ranks #2: This copper-core NGK set is a performance-oriented candidate, with eight plugs and a listed 1 mm gap; the listing specifies Corvette applications.

A vehicle-specific application list is the clearest differentiator of this eight-plug NGK TR6 set: it is titled for 1997–2013 C5, Z06, and Grand Sport Corvette models. The listing specifies copper core material and a 1 mm gap, providing concrete details for application matching.

The eight-plug quantity aligns with the set’s Corvette-focused title, while the listed 1997–2013 C5, Z06, and Grand Sport applications give buyers a defined vehicle range to check. NGK identifies the core as copper, the top material as nickel, and the gap as 1 mm; those specifications help distinguish this plug from platinum or iridium alternatives. The listing also gives a 14 mm thread size. No supplied feature establishes a particular E85 suitability claim, so application matching remains essential.

Skip it if you need an iridium core; NGK 6619 Iridium LFR6AIX-11 offers iridium construction in a six-pack.

Corvette owners within the named 1997–2013 C5, Z06, and Grand Sport range can consider this set when the copper core, 1 mm gap, and 14 mm thread match their requirements. The listing does not support broader vehicle or E85 claims.

Listed on Amazon as: Spark Plugs Set of 8 – NGK TR6 for 1997-2013 C5, Z06, Grand Sport Corvette

#3 · Best Six-Pack Iridium

3. NGK 6619 Iridium

• Core Material: Iridium
• Top Material Type: Iridium
• Compatible with Vehicle Type: Car, Truck
• Thread Size: 14mm (Thread Diameter), 1.25mm (Thread Pitch)

Best for: Six-Plug Iridium Set.

Why it ranks #3: Its iridium construction is listed to resist carbon buildup and pre-ignition, and its six-plug pack offers a useful quantity for compatible applications.

A wider operating heat range than ordinary plugs is the defining claim for NGK’s six-pack of LFR6AIX-11 iridium plugs. NGK also says the design resists carbon buildup and pre-ignition, giving buyers two stated operating concerns to weigh when choosing plugs for an engine with demanding conditions.

The iridium core and stated wider heat-range operation distinguish this set from ordinary plugs in the supplied description. NGK says the plugs resist carbon buildup and pre-ignition, which makes those specific properties relevant to buyers considering operating conditions; the listing does not claim a dedicated E85 application. A patented triple-gasket sealing process is said to eliminate combustion-gas leakage. Six plugs are included, and the 14 mm thread diameter with 1.25 mm pitch provides concrete fitment information for application matching.

Skip it if you need a stated vehicle-specific fitment; NGK TR6 4177 is listed for C5, Z06, and Grand Sport Corvette applications.

This six-pack suits buyers whose application calls for the listed LFR6AIX-11 thread dimensions and who value NGK’s stated heat-range and sealing features. Match the plug to the engine specification; the supplied listing does not name a vehicle fitment.

Listed on Amazon as: NGK 6619 Iridium Spark Plugs LFR6AIX-11-6 Pack

#4 · Best OEM-Style Iridium

4. NGK 6418 Iridium

• Core Material: Iridium
• Top Material Type: Iridium
• Compatible with Vehicle Type: Car, Truck
• Thread Size: 14mm x 19mm

Best for: Four-Pack Iridium Replacement.

Why it ranks #4: The listing describes it as often specified as original equipment and gives a 0.04-inch gap; buyers must still check engine-specific fitment.

NGK identifies this four-pack of BKR6EIX plugs as iridium and notes that NGK plugs are often specified as original equipment. The listing gives a 0.04-inch gap and 14 mm by 19 mm thread dimensions, helping buyers compare the plug with an application’s requirements.

The iridium construction and listed 0.04-inch gap are the clearest specifications for comparing this four-pack with an engine’s plug requirements. NGK describes its plugs as offering OEM-style quality, reliability, and durability, and says they are often specified as original equipment; these are brand-level claims rather than a specific vehicle fitment. A 14 mm x 19 mm thread specification adds a practical matching detail. The listing explicitly advises researching engine, drivetrain, and quantity needs before purchase.

Skip it if you need eight plugs at once; NGK TR5GP G-Power Platinum is listed as an eight-piece set.

This NGK iridium four-pack suits buyers whose required gap, thread dimensions, and plug quantity match the listed specifications. The OEM-oriented description does not name a compatible vehicle, so application research is important, particularly for an E85 setup.

Listed on Amazon as: NGK # 6418 Iridium Spark Plugs BKR6EIX – 4 PCS NEW

#5 · Best Double-Iridium Design

5. Bosch 96315 Double Iridium

• Core Material: Iridium
• Top Material Type: Iridium
• Compatible with Vehicle Type: Car, SUV, Truck
• Thread Size: M14x1.25

Best for: Fine-Wire Double-Iridium.

Why it ranks #5: It uses an iridium firing pin and ground-electrode inlay, with the listing claiming four times the life of standard copper plugs.

Bosch’s 360-degree laser-welded ultra-fine iridium firing pin is the key feature, with the listing tying it to better ignitability and voltage requirements reduced by up to 24 percent. An iridium inlay on the ground electrode completes the double-iridium design.

The fine-wire firing pin and double-iridium electrodes connect the listed construction to practical ignition and maintenance claims: Bosch says the fine wire improves ignitability and can reduce voltage requirements by up to 24 percent, while the double-iridium design offers four times the life of standard copper plugs. Nickel-plated rolled threads are specified for corrosion resistance and easier removal. The four-pack and M14x1.25 thread size help define quantity and fitment considerations across the listed car, SUV, and truck categories.

Skip it if you need six plugs in one set; NGK 6619 Iridium LFR6AIX-11 is sold as a six-pack.

Consider this Bosch set when its four-plug quantity and M14x1.25 thread specification match the application, and when the stated fine-wire and double-iridium benefits matter. The listing covers car, SUV, and truck types, not a specific E85 engine.

Listed on Amazon as: BOSCH 96315 OE Fine Wire Double Iridium Spark Plug – Pack of 4

#6

6. X4XZ 1208 Double Iridium

• Core Material: Iridium
• Top Material Type: Iridium
• Compatible with Vehicle Type: Car
• Thread Size: M12

Best for: BMW Double-Iridium Set.

Why it ranks #6: Its six-piece double-iridium set lists broad BMW model fitment, including Z4 Roadster E85; that chassis code does not verify E85 fuel compatibility.

Double-iridium construction and a long list of BMW applications define X4XZ’s six-plug ILZFR6D11 set. The listed fitments span several BMW series and model years, from 1 Series through X5 and Z4, giving BMW owners a broad application list to check against their vehicle.

The product title identifies a six-piece double-iridium set, while the fitment list names BMW 1, 3, 5, 6, and 7 Series, X1, X3, X5, and Z4 applications across specified years. That breadth makes the application list central to selection rather than assuming every BMW is covered. The listed M12 thread size is another specification to compare with the engine requirement. Since the listing asks buyers to check its compatibility image, this is a fitment-specific replacement, not a general-purpose E85 recommendation.

Skip it if you need plugs for a non-BMW application; NGK 7090 BKR5EGP is listed for cars and trucks.

BMW owners whose vehicle appears in the supplied application list can consider this six-piece double-iridium set, especially when its M12 thread specification matches their requirement. The extensive list still has defined model-year boundaries and does not establish universal BMW or E85 fitment.

Listed on Amazon as: 1208 Double Iridium Spark Plug 6PCS ILZFR6D11 for 2004-2015 BMW 1/3/5/6/7

#7

7. POCYBER Iridium Plug

• Core Material: Iridium
• Top Material Type: Iridium
• Compatible with Vehicle Type: Car
• Thread Size: RM

Best for: BMW Iridium Replacement Set.

Why it ranks #7: The six-plug set lists iridium and platinum construction, factory pre-gapping, and BMW/SAAB replacement numbers, but requires exact application confirmation.

An iridium firing pin paired with a platinum inlay is the defining feature of POCYBER’s six-plug set, and the listing says this combination provides three times the service life of standard copper plugs. Factory pre-gapping removes a gap-adjustment step, while nickel-plated rolled threads support corrosion resistance during installation.

For a BMW or SAAB application covered by the listing, this set combines named OEM replacement references with a six-plug quantity, giving buyers a specific replacement path and a matched set. Factory pre-gapping means the plugs require no gap adjustment before installation, and nickel-plated rolled threads are described as corrosion-resistant and installable without anti-seize. The iridium firing pin and platinum inlay are listed as lasting three times longer than standard copper plugs; that longevity claim is the relevant distinction for maintenance planning.

Skip it if you need a plug for an application outside the listed BMW and SAAB fitments; NGK 7090 BKR5EGP is listed for cars and trucks.

BMW or SAAB owners seeking a pre-gapped iridium-and-platinum replacement set may value the simplified installation and stated service-life advantage. Treat the listed vehicle fitments and OEM references as the boundary; this is not presented as a universal E85 plug.

Listed on Amazon as: Set of 6 Spark Plugs Iridium Plug for BMW E60 E83 E85 E90 X5 Replace OEM 158253 12120035915 12122158253

#8

8. NGK TR5GP Platinum

• Core Material: Platinum
• Top Material Type: Platinum
• Compatible with Vehicle Type: Car, Truck
• Thread Size: 14×1.25mm

Best for: Eight-Pack Platinum G-Power.

Why it ranks #8: This eight-piece platinum set is listed to resist carbon buildup and pre-ignition, but its application and gap are not specified in the provided details.

NGK’s G-Power platinum plugs are described as operating over a wider heat range than ordinary plugs, making heat-range behavior the set’s primary differentiator. The listing also says they resist carbon buildup and pre-ignition, and supplies eight plugs for buyers needing a larger quantity.

The platinum core and wider stated operating heat range distinguish this NGK set from ordinary plugs, while the description specifically cites resistance to carbon buildup and pre-ignition. Those claims give buyers concrete design considerations without establishing a dedicated E85 application. NGK’s patented triple-gasket sealing process is said to eliminate the possibility of combustion-gas leakage. Eight plugs are included, and the listed 14×1.25 mm thread specification helps with application matching before installation.

Skip it if you need a named vehicle-specific fitment; NGK TR6 4177 lists C5, Z06, and Grand Sport Corvette applications.

Buyers needing eight platinum plugs can consider this set for its stated heat-range, fouling-resistance, and gasket features. Check the listed 14×1.25 mm thread against the engine requirement; the supplied details do not name a particular vehicle or confirm E85 use.

Listed on Amazon as: NGK # 3186 G-Power Platinum Spark Plugs TR5GP – 8 PCSNEW

#9

9. ACDelco 41-962 Platinum

• Core Material: Platinum
• Top Material Type: Nickel
• Compatible with Vehicle Type: Car
• Thread Size: 14 millimeters

Best for: Eight-Plug Platinum Pack.

Why it ranks #9: Its double-platinum pads and copper core are stated features, and the eight-plug quantity is useful only when the vehicle application matches.

Double platinum pads on both the center and ground electrodes are the defining feature of ACDelco’s eight-plug Professional set. The listing says they support durability and consistent voltage demands while helping reduce ignition-system wear, making electrode construction the central selection point.

This eight-piece set pairs double platinum electrode pads with a pure copper core. ACDelco says the platinum pads offer durability and consistent voltage demands that help reduce wear on the ignition system, while the copper core results in a cooler electrode temperature for durability. The one-piece fired-in suppressor seal combines three glass types to help create a gas-tight seal, regulate spark energy, and reduce radio-frequency and engine interference. Its 14 mm thread size is a useful application-matching specification.

Skip it if you need a named vehicle-specific application; NGK TR6 4177 is listed for C5, Z06, and Grand Sport Corvette models.

This ACDelco pack is suited to buyers who need eight plugs and value double-platinum electrodes plus the listed suppressor-seal features. Check the engine’s application and 14 mm thread requirement, since the supplied details do not specify particular vehicle fitments.

Listed on Amazon as: ACDelco 41-962 Professional Platinum Spark Plug, (8)

#10

10. NGK 7090 G-Power

• Core Material: Platinum
• Top Material Type: Nickel
• Compatible with Vehicle Type: Car, Truck
• Thread Size: 14 millimeters

Best for: Platinum Daily-Use Set.

Why it ranks #10: This platinum plug lists a 0.6 mm gap, but the supplied details provide little performance or E85-specific evidence to support this use case.

NGK’s 0.6 mm platinum-alloy tip, laser-welded to the center electrode according to the product description, is the key distinction of this four-plug G-Power set. The description connects platinum construction with quicker starts, lower emissions, and improved fuel efficiency, while the listing specifies a 0.6 mm gap.

The platinum center tip and stated 0.6 mm gap give buyers concrete electrode and gap specifications to compare with an application’s requirements. NGK describes the platinum plug as intended to improve fuel efficiency, lower emissions, and provide quicker starts while remaining durable under high heat. Its listed 14 mm thread size and car-and-truck vehicle types offer further selection details, but the supplied information does not establish compatibility with a particular E85 engine. The pack contains four plugs.

Skip it if you need a six-plug set; NGK 6619 Iridium LFR6AIX-11 is listed as a six-pack.

Choose this NGK set when a four-plug quantity, platinum construction, and the listed 0.6 mm gap suit your vehicle’s requirements. The supplied details do not identify a specific E85 application, so verify the engine’s required plug specification before selecting it.

Listed on Amazon as: NGK 7090 BKR5EGP G-Power Spark Plug, Pack of 4