Original U-Groove

Features:

100 percent pre-fired to ensure reliable operation
Copper core center electrode for superior thermal conductivity
Unique five-rib insulator reduces flashover and decreases voltage loss
Dual copper and glass seal bonds the center electrode and insulator together for a gas-tight seal.
Original Equipment in automotive applications

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Patented U-Groove ground electrode design fires leaner mixtures than conventional plugs

Precision machine-rolled threads reduce seizing and cross-threading in delicate aluminum heads

Wide range of part numbers for thousands of applications, including classic and collector cars

Lasts twice as long as conventional plugs

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The U-Groove is Engineered for Greater Fuel Efficiency and Improved Throttle Response

DENSO’s patented U-Groove spark plug enables complete combustion by allowing the spark to fill the gap created by the U shape. The ball of fire created in the U-Groove develops a larger and hotter flash front that virtually eliminates excessive fouling and erratic starts caused by poor fuel mixtures.

Even DENSO’s “standard” spark plug is something special. The innovative design that helped to make DENSO spark plugs famous, the U-Groove plug employs a unique, channeled ground electrode designed to generate a larger spark nucleus at the point of ignition. Greater spark energy than ordinary plugs means improved flame travel, producing more complete, consistent, and efficient combustion.

Unique U-Groove Ground Electrode

The unique U-Groove ground electrode is one of the finest features of DENSO spark plugs. The electrode was developed to meet the demand for improved ignitability, necessary for increased efficiency in emission gas purification and fuel consumption.

Improved Ignitability

With the U-Groove ground electrode, firing can be greatly improved without increasing the spark plug gap.

Better Fuel Efficiency and Improved Throttle Response

The U-Groove ground electrode provides a larger spark stimulation and more complete combustion, resulting in better fuel efficiency and improved throttle response.