The Denso Iridium spark plugs are the finest spark plugs available today. They are the result of continual research, development, and evolution in the field of spark plug technology and manufacture. They not only use the properties of Iridium to last some 60,000 miles, but they utilize these properties to enable a more powerful spark at LESS voltage, allowing wider spark gaps to be utilized and typically yielding small increases in power. When every horsepower counts, these are the plugs to run, and they are the plugs you will find in our SCCA Spec Miatas- one of the most closely contented racing classes around.
This is for one UNGAPPED Denso Iridium Plug. To buy more, purchase this one, and change the quantity during checkout. Please check out our GAPPED versions of this plug because these plugs are extremely easy to damage during gapping.
Heat Range Recommendations:
| Engine | Plug | Application |
| 1.8t | IK20 | Stock |
| 1.8t | IK22 | Chipped Cars |
| 1.8t | IK24 | Big Turbo Cars |
| 1.8t | IK27 | Extreme Big turbo cars- High boost race fuel only! |
| VR6 | IK20 | Bolt ons / light nitrous |
| VR6 | IK22 | Turbo / Supercharged Cars |
| VR6 | IK24 | Extreme Turbo / Supercharged |
The U-Groove Design
In 1972, DENSO received a patent for the popular U-Groove ground electrode design. This electrode was developed to meet the demand for improved ignitability, which is necessary for an increase of efficiency in emission gas purification and fuel consumption. The U-Groove gives the flame a groove to grow in, thereby creating a larger flame front for a more complete combustion even in the case of lean air-fuel mixture. A conventional, flat ground electrode design of regular plugs crushes the flame preventing full spark potential.
Ultra Fine Electrode
By harnessing the power of Iridium, DENSO is suddenly able to shrink the surface area of the center electrode – the critical component of a spark plug. Unlike a typical platinum plug that has a 1.1mm diameter center electrode, DENSO Iridium Power plugs have the world's smallest center electrode measuring 0.4mm in diameter. This means that the voltage requirements are decreased while firing performance is greatly improved.
Tapered Cut
To help improve ignitability DENSO minimized the portion of the ground electrode that comes in contact with the flame nucleus. Because the area of the ground electrode where the tapered cut comes into contact with the flame nucleus is small, the heat lost to the electrode is lessened and firing performance improves dramatically. The surface area and weight of the ground electrode tip is reduced along with the load in terms of heat and vibrations. This means the spark plug can cope with heavier driving conditions.
