The NGK LFR7AIX Iridium IX Spark Plug is a premium ignition upgrade designed to deliver consistent spark energy, improved combustion efficiency, and long-lasting durability for Gen 3 HEMI engines. Built with NGK’s proven Iridium IX technology, this spark plug features an ultra-fine laser-welded iridium center electrode that requires less voltage to fire while producing a stronger, more reliable spark. Whether you’re maintaining a stock daily driver or supporting a modified performance build, the LFR7AIX provides excellent ignition performance for naturally aspirated, supercharged, turbocharged, and nitrous-assisted applications.
Compared to conventional nickel plugs, the NGK Iridium IX design offers improved resistance to wear and erosion, allowing the spark plug to maintain a consistent gap over a much longer service life. The fine-wire center electrode enhances flame kernel development for more efficient combustion, which can contribute to smoother idle quality, improved throttle response, easier cold starts, and dependable performance under high engine loads. For Gen 3 HEMI enthusiasts running aftermarket camshafts, upgraded ignition systems, E85, forced induction, or other power-adding modifications, a high-quality spark plug is essential for maximizing performance and reliability.
NGK has long been recognized as one of the industry’s leading ignition manufacturers, and the LFR7AIX continues that reputation with precision manufacturing and OE-level quality. Its trivalent metal plating helps resist corrosion and seizure, while the advanced ceramic insulator provides superior dielectric strength and efficient heat dissipation. The plug’s projected tip design promotes stable combustion and reliable ignition across a broad operating range, making it suitable for both everyday street driving and demanding motorsports applications.
The LFR7AIX is commonly selected by Gen 3 HEMI owners looking to improve ignition performance while maintaining exceptional reliability. Whether you’re servicing a 5.7L HEMI, 6.1L HEMI, 6.4L (392) HEMI, or many supercharged 6.2L combinations using an appropriate heat range for your build, these plugs are an excellent choice when paired with proper tuning and regular maintenance. Installing fresh spark plugs is one of the simplest ways to maintain horsepower, fuel efficiency, and engine responsiveness while reducing the likelihood of misfires under heavy load.
At Dusterhoff Racing, we recommend premium NGK spark plugs for customers building everything from mild bolt-on street cars to high-horsepower Gen 3 HEMI race vehicles. Pair the NGK LFR7AIX with upgraded ignition coils, custom tuning, flex fuel conversions, or one of our complete performance packages to ensure your engine delivers consistent power every time you hit the throttle. For additional ignition and maintenance components, browse our catalog.
Specifications & Features
Manufacturer: NGK
Product Name: Iridium IX Spark Plug
Manufacturer Part Number: 2309
NGK Stock Number: LFR7AIX
Product Type: Performance Spark Plug
Electrode Material: Fine-Wire Iridium Center Electrode
Ground Electrode: Nickel Alloy
Laser-Welded Iridium Tip
Projected Tip Design
Trivalent Metal Plating for Corrosion Resistance
Advanced Ceramic Insulator
Resists Fouling and Wear
Excellent High-RPM Performance
Improved Throttle Response
Smooth Idle Characteristics
Enhanced Cold Starting
Long Service Life
Ideal for Naturally Aspirated and Forced Induction Applications
Suitable for Street and Racing Use
Engine Compatibility:
5.7L Gen 3 HEMI
6.1L Gen 3 HEMI
6.4L (392) Gen 3 HEMI
Compatible 6.2L Supercharged Gen 3 HEMI Applications (Verify Heat Range for Specific Build)
Vehicle Compatibility:
Dodge Challenger
Dodge Charger
Chrysler 300
Dodge Magnum
Jeep Grand Cherokee
Jeep Grand Cherokee Trackhawk
Dodge Durango
Dodge Durango Hellcat
Ram 1500
Ram 1500 TRX
Year Compatibility: Application Specific (Verify Fitment Before Ordering)
Color: White Ceramic with Silver Metal Shell
Weight: Approximately 0.1 lbs. Each
Quantity: Sold Individually
Installation: Direct Replacement
Recommended Gap: Verify Based on Vehicle and Performance Application
Recommended Supporting Components:
Ignition Coils
Coil Boots
Spark Plug Socket
Custom ECU Tune
Professional Installation Recommended: No (Basic Hand Tools Required)
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