SPS

Frequently Asked Questions

Q. Where does Iridium come from?
A. Fifty million years ago, an asteroid composed almost entirely of the precious metal Iridium (Ir-77) struck the earth, creating the Gulf of Mexico. The resulting dust cloud destroyed most living things and ended the dinosaurs reign on earth.

Q. Why was Iridium not used until today?
A. The extreme strength of the metal inhibited its large-scale usage in spark plugs. However, through recent technological advances, DENSO has harnessed the power of Iridium. DENSO’s patented alloy is composed of iridium, complimented by rhodium (an even stronger metal). The rhodium is added to increase oxidation and wear resistance. DENSO was able to make this durable alloy workable by pioneering and patenting a Laser-Welding/process. This process provides a 360-degree weld so reliable that the electrode resists wear, even in the harshest conditions.

Q. What makes Iridium better?
A. Until recently, platinum was considered the best material to use on the top of an electrode because of its durability. However, Iridium is 6 times harder, 8 times stronger, and has a melting point 1200 degrees higher than platinum. Put that into a harsh environment such as an engine piston chamber, and you have a spark plug that can resist wear much better than platinum. Additionally, the DENSO Iridium Power alloy is so durable; it allowed our engineers to produce the world’s smallest center electrode (.4mm) which reduces the voltage requirements, concentrating its sparking power. Also, its smaller size, combined with the tapered U-Groove ground electrode, allows more room for the flame kernel to develop and produce a more efficient combustion.

Q. How long will Iridium Last?
A. Iridium use represents the most significant technological advance in automotive spark plug manufacturing, since platinum was introduced in the early eighties. As vehicle manufacturers produce increasingly complex and efficient automobiles, there is a greater need for long-life plugs that can tolerate leaner fuel mixtures and improved combustion processes. DENSO has responded to this need by developing its Iridium alloy, originally for OE applications. For example, many newer Lexus’ and Toyota models carry an ultra long-life Iridium plug variation (.7mm with platinum tipped ground) that is capable of up to 120,000 miles of service. DENSO Iridium Power plugs, with their .4mm center electrode, have been developed for performance applications. Because gradual wear will “round-off” firing points over time, the concentrated firing power and voltage requirement benefits will be reduced. For this reason, DENSO advises replacement after 30,000 miles.

Q. Why is the U-Groove special?
A. The patented U-Groove allows the flame kernel to fill the gap formed by the U. This ball of fire develops a larger and hotter flash front a complete combustion. The flat ground electrode design of ordinary spark plugs crush the spark, inhibiting its growth; this effect is known as a “quenching effect.” The simple, but efficient, U-Groove feature results in better fuel efficiency, improved throttle response, and greater firing energy.

Q. Do I need to set the gap?
A. Generally, no. The DENSO Iridium Power plug comes pre-set with a protective sleeve over the firing end, to protect the gap from accidental alteration. DENSO Iridium Power’s ultra-efficient firing power compensates for normally recommended gap settings that are smaller than the pre-set value. In the cases of vehicle modifications (nitrous, turbo-chargers, super-chargers, high power ignition systems, etc.), some adjustments may be desired. Or, if you prefer to remain consistent with factory specifications, you may adjust. However, please be careful not to place any stress on the fine center electrode during adjustment. You could accidentally break off the very hard, and therefore brittle, tip.

Q. What kind of performance will I get from this plug?
A. Generally, you do not purchase spark plugs for performance enhancement. While DENSO Iridium Power spark plugs have contributed to numerous accomplishments through dyno-testing and actual use, their true benefit lies in their efficiency, durability, and improved firing power. Serious tuners modify their vehicles by increasing boost through turbo-chargers, super-chargers, and Nitrous. They are also known to add high-energy ignition systems, tinker with timing, adjust fuel mixture ratios, and increase horsepower through other means. Putting these kinds of demands on their engine increases the need for an efficient, durable spark plug that can handle these kind of harsh environments. That’s where DENSO Iridium Power can make a major difference.

Q. What kind of testing has been done?
A. Iridium Power has been tested in many arenas. The most common area of testing has been on the track. There are currently many people using the plugs in import drag racing, with results being quite favorable. Some racers have seen E.T.’s decrease by a tenth and less fuel consumption during a pass. Circle track racers using the plugs notice better acceleration coming out of corners and more consistent idling. The other area where the plugs have been tested is the dynamometer . The results have fluctuated from 2-3 horsepower to 40 horsepower (all tests performed by independent companies DENSO can not confirm or deny these claims). The differences in dyno results are due to the complexity of the engine being tested. In general the plugs have shown a 2-5% increase in efficiency of the engine. 

For more information, visit the DENSO website.