DENSO 5304 Iridium Power Spark Plug - IK20

The DENSO 5304 (IK20) Iridium Power Spark Plug delivers exceptional ignition performance through a combination of advanced electrode technology and precision engineering. Featuring a ultra-fine 0.4mm iridium center electrode — laser welded for durability — this plug reduces the voltage required to fire while significantly improving ignitability and combustion efficiency.

Iridium is not only a better electrical conductor than platinum, it is also considerably harder and stronger, allowing DENSO to machine the center electrode to an extremely fine 0.4mm diameter. This ultra-fine tip produces a more focused spark, resulting in improved throttle response and stronger acceleration compared to standard spark plugs.

Key Features:

• 0.4mm iridium fine-wire center electrode — laser welded for maximum durability and ignitability
• Tapered cut U-Groove ground electrode — increases ignitability and reduces quenching for a larger, more powerful flame kernel
• Machine rolled threads — prevent seizing or cross-threading during installation and removal
• 100% pre-fired — every plug is pre-fired at the factory to ensure the highest quality
• Purified alumina powder insulator — provides exceptional strength and thermal conductivity
• Five-rib insulator design — prevents flashover
• Copper-glass seal — bonds center electrode and insulator for a gas-tight seal
• 5,000-ohm monolithic resistor — reduces electromagnetic interference with vehicle electronics
• Burnished nickel-plated shell — resists corrosion and rust in harsh conditions

Specifications:

• Thread Diameter: 14mm
• Thread Pitch: 1.25mm
• Reach: 19mm (3/4")
• Hex Size: 5/8" (16mm)
• Seat Type: Gasket
• Gap: 0.043" (1.1mm)
• Center Electrode Material: Iridium, Fine Wire, 0.4mm
• Ground Electrode: Nickel, U-Groove, Taper Cut
• Resistor: Yes — 5k Ohm
• Heat Range: 20
• Terminal Type: Solid (removable nut included)

Torque Specifications:

• Cast Iron Head: 26–30 lb-ft
• Aluminum Head: 15–22 lb-ft

The DENSO IK20 Iridium Power spark plug is sold individually and is compatible with a wide range of automotive applications. Always confirm fitment for your specific vehicle before installation.