Denso Iridium TT Spark Plugs IKH16TT 4-Pack — Twin-Tip Iridium, Long Life & Crisp Ignition

Denso IKH16TT Iridium TT spark plugs pair a 0.4mm iridium center electrode with a 0.7mm needle ground tip to deliver longer life, sharper ignitions, and improved throttle response.

These Denso Iridium TT plugs combine precision metallurgy and advanced manufacturing for reliable ignition across tens of thousands of miles. Built with Denso’s high-iridium alloy and 360-degree laser welding, the IKH16TT is engineered to resist wear while focusing spark energy where it matters. The Twin-Tip (TT) design concentrates the spark to improve ignitability, potentially helping optimize fuel use and throttle feel without changing your engine’s tuning.

How does the Twin-Tip design affect starting and acceleration?

The Twin-Tip configuration funnels spark energy between a fine iridium center and a needle-like ground electrode so combustion starts more reliably and cleanly. Drivers often notice crisper throttle response and steadier acceleration because each ignition event is more concentrated.

• 0.4mm iridium center electrode for precise spark initiation
• 0.7mm needle ground electrode to minimize spark scatter
• Sharper ignition helps reduce misfires at startup and under load

What makes these plugs last over 100,000 miles?

Denso’s patented iridium alloy and laser-welded construction resist electrode erosion and maintain a consistent gap for far longer than conventional plugs. Combined with a copper-glass seal and purified alumina insulator, the IKH16TT keeps its integrity under high heat and repeated combustion cycles.

• High-iridium concentration for superior hardness and wear resistance
• 360-degree laser welding secures the electrode to the core
• Purified alumina insulator improves thermal durability

Are they easy to install and reliable over time?

Denso trims common installation issues by using machine-rolled threads and factory pre-firing so plugs fit smoothly and perform consistently out of the box. Five ribs on the insulator reduce flashover risk, while the copper-glass seal maintains a gas-tight connection between electrode and insulator.

• Machine-rolled threads reduce cross-threading during installation
• 100% pre-fired for consistent quality and immediate use
• Five-rib insulator prevents flashover and stray current paths

How do these plugs help with fuel economy and emissions?

By improving ignitability and reducing misfires, the IKH16TT can contribute to more complete combustion events. While exact savings vary by vehicle and driving habits, a cleaner, more consistent burn tends to support smoother operation and can help your engine run nearer to its designed efficiency.

• Concentrated sparks promote fuller combustion of the air-fuel mixture
• Reduced electrode wear preserves optimal gap and ignition timing
• Improved torque and power delivery under normal driving conditions

Who is this for? The Denso IKH16TT Iridium TT spark plugs are aimed at drivers who want durable, high-performance ignition components for modern gasoline engines — especially those seeking long service intervals, sharper throttle response, and dependable starting. They suit everyday commuters, performance-minded owners, and technicians who prefer premium OE-style replacement parts that focus on longevity and consistent combustion quality.