DENSO 5361 Iridium Power Spark Plug - IU22

The DENSO 5361 (IU22) Iridium Power Spark Plug delivers exceptional ignition performance through advanced iridium electrode technology. Featuring the world's smallest 0.4mm iridium alloy center electrode, this plug reduces required firing voltage while dramatically improving spark performance, resulting in more complete combustion and improved engine response.

DENSO's patented U-Groove tapered cut ground electrode maximizes ignitability by allowing the flame kernel to grow freely and unobstructed after ignition, minimizing heat quenching that can rob power. This innovative design achieves higher ignitability without the need for a wider spark gap—keeping voltage requirements low while delivering a stronger, more consistent spark.

Key Features:

• 0.4mm Iridium Alloy Center Electrode — the world's smallest, reducing required voltage and boosting firing performance
• Patented 360° Laser Welding Process — creates an exceptionally strong, durable bond between the iridium tip and center electrode
• Tapered Cut U-Groove Ground Electrode — increases ignitability and reduces quenching for faster flame kernel growth
• Iridium withstands temperatures exceeding 4,000°F — six times harder than platinum for long-lasting durability
• Machine-rolled threads — prevent cross-threading and seizing during installation and removal
• Purified alumina powder insulator — provides exceptional strength and superior thermal conductivity
• Five-rib insulator design — prevents flashover for consistent, reliable ignition
• Copper-glass seal — bonds center electrode and insulator for a gas-tight seal
• 100% pre-fired at the factory — ensures highest quality and consistent performance out of the box
• 14mm thread, 19mm reach, gasket seat — fits a wide range of powersports applications

Torque Specifications: 7–11 lb-ft for both cast iron and aluminum cylinder heads.

The DENSO 5361 IU22 is engineered for powersports applications including motorcycles, ATVs, UTVs, scooters, and personal watercraft. It is sold individually and carries the DENSO OEM part number IU22 (UPC: 042511053618). Whether used as a direct OEM replacement or as a performance upgrade, the Iridium Power plug delivers measurable gains in acceleration and combustion efficiency.