NGK Spark Plug LFR6AIX-11 / 6619 Iridium

NGK LFR6AIX-11 Iridium IX Spark Plug – 6619

Upgrade ignition performance with the NGK LFR6AIX-11 Iridium IX Spark Plug. Designed for high ignitability and dependable performance, this premium spark plug features a fine-wire iridium center electrode and tapered-cut nickel ground electrode to deliver a strong, consistent spark while reducing quenching.

The LFR6AIX-11 is part of NGK’s performance-oriented Iridium IX series. Its 0.6 mm fine-wire iridium center electrode helps provide reliable ignition, while the tapered ground electrode design promotes improved starting, stable idle, and responsive throttle performance. A solid copper core provides efficient heat dissipation for consistent operation across a wide range of driving conditions.

Features & Benefits

• Premium NGK Iridium IX construction
• 0.6 mm fine-wire iridium center electrode
• High-ignitability design provides a strong, consistent spark
• Tapered-cut ground electrode helps reduce spark quenching
• Designed for improved starting, idle, and throttle response
• Excellent anti-fouling characteristics
• Solid copper core provides efficient heat dissipation
• High-strength ceramic insulator
• Corrugated ribs help prevent flashover
• Triple seals help prevent combustion gas leakage
• Trivalent metal plating provides corrosion and anti-seizing protection
• Excellent durability in high-temperature engine environments
• Suitable for performance applications and upgrades from conventional nickel spark plugs

Specifications

• Brand: NGK
• Part Number: LFR6AIX-11
• NGK Stock Number: 6619
• Series: Iridium IX
• Thread Size: M14 x 1.25
• Reach: 26.5 mm / 1.043 in
• Hex Size: 16 mm / 5/8 in
• Seat Type: Gasket / Flat
• Heat Range: NGK 6
• Pre-Set Gap: 0.044 in / 1.1 mm
• Resistor Type: Yes
• Resistance: 5,000 ohms
• Center Electrode: Fine-Wire Iridium
• Center Electrode Diameter: 0.6 mm
• Center Electrode Core: Copper
• Ground Electrode: Nickel
• Ground Electrode Design: Taper Cut
• Ground Configuration: J-Gap
• Insulator: Ceramic
• Terminal Type: Non-Removable Nut

Vehicle Fitment

The NGK LFR6AIX-11 / 6619 is used in a wide range of automotive and other engine applications. Fitment varies considerably by year, make, model, engine, and original spark plug specification.

Common applications include select vehicles from manufacturers such as:

• Acura / Honda

• Chevrolet / GMC

• Ford

• Infiniti / Nissan

• Lexus / Toyota

• Mitsubishi

• Subaru

• Volvo

The LFR6AIX-11 is also used in select marine and powersports applications.

Please verify NGK part number LFR6AIX-11 / stock number 6619 against your vehicle or engine’s original spark plug and manufacturer specifications before ordering.

Why Choose NGK Iridium IX?

NGK Iridium IX spark plugs are engineered for drivers looking for improved ignitability and dependable performance. The fine-wire iridium center electrode requires less voltage to produce a spark, while the tapered-cut ground electrode helps reduce quenching around the spark area.

Combined with NGK’s copper-core construction, high-grade ceramic insulator, and corrosion-resistant shell plating, Iridium IX spark plugs provide reliable ignition performance and excellent durability for modern and performance-oriented engines.