Denso Iridium TT Spark Plugs IKH16TT 4-Pack — 0.4mm Iridium Center, Twin‑Tip for Better Ignition and Longevity

Denso IKH16TT Iridium TT spark plugs are high-performance, long-life ignition plugs built with a 0.4mm iridium center electrode and Twin‑Tip design for better ignitability, fuel economy, and durability.

These IKH16TT plugs combine Denso’s iridium and platinum materials with a 360-degree laser‑welded construction to deliver an extended service life and consistent spark performance. Engineered to minimize electrode interference and maximize spark concentration, the Twin‑Tip (TT) configuration helps engines start quicker and run cleaner under a wide range of driving conditions. Each 4703-4 PK set includes four pre-fired, machine‑threaded plugs ready for reliable installation.

How do these plugs enhance ignition performance?

Denso Iridium TT plugs concentrate spark energy on a fine iridium center electrode and a needle‑thin ground electrode to create a more focused, reliable spark. This design improves the plug’s ability to ignite the air–fuel mixture more consistently across rpm ranges, which supports smoother throttle response and steadier combustion.

• 0.4mm iridium center electrode for precise spark formation
• 0.7mm needle tip ground electrode reduces spark energy loss
• Twin‑Tip design focuses the spark and reduces misfires
• 360° laser welding ensures a secure electrode bond

Will these plugs last longer than standard spark plugs?

Yes — Denso’s patented iridium alloy and the durable laser‑weld process extend service life well beyond conventional plugs. The materials and construction are selected to resist wear, helping the plugs maintain consistent gap and performance for many miles.

• High‑concentration iridium alloy for superior electrode wear resistance
• Platinum elements add stability under high heat
• Pre‑fired quality control reduces early failures
• Designed for service life exceeding 100,000 miles under normal conditions

What installation and reliability features should I expect?

Denso builds these plugs with installer‑friendly and engine‑safe features to minimize problems during service. Machine‑rolled threads and a copper‑glass seal improve fit, prevent seizing, and keep combustion gases contained around the insulator.

• Machine‑rolled threads to prevent cross‑threading and seizure
• Copper‑glass seal for a gas‑tight bond between electrode and insulator
• Purified alumina insulator for strength and thermal conductivity
• Five‑rib insulator design to prevent flashover and improve reliability

How will these plugs impact everyday driving and fuel economy?

By improving ignitability and promoting more complete combustion, Iridium TT plugs can help engines run more efficiently and respond better to throttle inputs. While actual fuel savings depend on driving habits and vehicle condition, many drivers notice smoother acceleration and steadier idling after installation.

• Improved ignitability can reduce incomplete combustion events
• Smoother power delivery and faster throttle response
• Consistent spark reduces rough idling and hesitation
• Longer service intervals compared with conventional plugs

Who is this for: Drivers and technicians who want a high‑durability, performance‑oriented replacement spark plug that balances longevity with improved ignition. Ideal for modern gasoline engines where stable, concentrated spark and long intervals between changes are priorities — especially for owners seeking reduced maintenance frequency and predictable engine response.