The DENSO Iridium TT 4705 is a high-performance spark plug built around a 0.4 mm iridium center electrode and a 0.7 mm needle-tip ground electrode. Its design is intended to support more efficient combustion and stable ignition under high engine loads. The specifications highlight advanced alloy construction, laser welding and fitment requirements relevant to automotive maintenance and tuning applications.
The spark plug’s central design feature is its 0.4 mm iridium center electrode, identified as one of the smallest center-electrode diameters available. A finer electrode is intended to concentrate electrical potential and make it easier for the flame core to form, supporting more complete combustion.
The component also uses a 0.7 mm needle-tip ground electrode. This configuration is designed to strengthen spark energy while reducing the heat-quenching effect, a factor that can affect ignition stability. Under high-load operation, the design is intended to maintain consistent ignition energy.
| Technical feature | Specification or description |
|---|---|
| Center electrode | 0.4 mm iridium; described as one of the smallest diameters available |
| Ground electrode | 0.7 mm needle-tip design |
| Alloy formulation | Patented iridium-rhodium alloy |
| Welding process | 360-degree laser welding |
| Temperature limit | Above 4,000 degrees Fahrenheit |
| Seat type | Flat seat |
Durability is a key measure of spark plug quality. The product uses a patented iridium-rhodium alloy formulation that, according to the specifications, has a high iridium content and is intended to resist high-temperature corrosion and electrode wear. The material combination is designed to preserve ignition performance over extended use.
To support structural strength, the manufacturer uses 360-degree laser welding. The process secures the iridium center electrode to the base and is intended to maintain structural integrity under extreme temperatures above 4,000 degrees Fahrenheit and under high-pressure vibration, reducing the risk of electrode detachment or seal failure.
The Iridium TT 4705 is designed to combine OE-level durability with the performance gains associated with high-performance engineering. For vehicles used in long-distance driving or high-load conditions, the design is intended to provide smoother acceleration and stronger torque output. Its flat-seat design is meant to accommodate multiple engine types, although exact fitment depends on the vehicle’s specifications.
Although the spark plug features a flat-seat design, selection must follow the vehicle manufacturer’s specification manual. Before installation, the thread diameter, thread length, heat range and seat type should be checked to ensure a complete match with the engine.
Installation should be performed with a torque wrench set to the torque value specified in the vehicle service manual. Because the electrode design is precise, the tip should not be struck during installation, as impact could alter the gap or damage the structure.
