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For drivers that care about performance.

By using a 0.4mm diameter iridium alloy center electrode and a special ground electrode, IRIDIUM POWER realizes spark performance unseen until now. It steadily gives a high level of response under a variety of driving conditions. The result? Increased acceleration and torque compared to regular plugs.

For drivers that care about mileage.

If you use your car on a daily basis, you may be concerned about fuel consumption. IRIDIUM POWER is one solution.


Specifications Include Terminal

A terminal nut is attached that fits with most of the world’s spark plug cables. Please remove the nut for installations that do not require one. (The terminal nuts on the IWM and IK-G types are solid parts and cannot be removed.)

Built-in, Highly Reliable Resistor

All IRIDIUM POWER plugs include a highly reliable, 5,000 ohm monolithic resistor specification to reduce electromagnetic noise that may affect electronic devices. (For all plug types)

Highly Corrosion Resistant, Burnished Nickel Plating

The plug housing is plated with burnished nickel, the same as plugs used for racing. It is highly resistant to corrosion and rust even while touring in continually rainy weather and during motocross events. (Low-heat range types excluded)

360° Laser Welding

The process used to mount the iridium tip is a highly reliable “All-around Laser Welding” process that is able to withstand all kinds of driving conditions. (For all plug types)

Projected Center Electrode

In order to improve ignitability, the center electrode protrudes more than with conventional type plugs. This improves both acceleration response time and performance.(Only with: IU31, IUH24, IUH27, IX22, IX24, IX27, IUF22, IUF24, IWF22, IWF24, IWF27, IW24, IW27, IW29, IW31, and IW34)

φ0.4 mm Diameter Ultra-fine Iridium Center Electrode

Using a new iridium alloy with a very high melting point, the tip of the electrode can be made very fine. This enables the reduction of voltage necessary to cause the spark, and greatly improves ignitability. Moreover, the special iridium alloy used was developed by DENSO

Taper-cut Ground Electrode

The tip of the ground electrode is cut to a fine taper to reduce the adverse effects of quenching, which greatly improves fuel ignitability. Also, because of the streamlined, taper-cut shape, the fuel-air mixture spreads more evenly in the gap, resulting in steady, reliable igniting of combustion.(excluding IUF27A, IUF31A, IU24A, IU27A, IU31A, IY24, IY27 & IY31)

U-Groove Ground Electrode

The U-shaped groove on the ground electrode insures that the inside surface area is large enough to generate the flame kernel. This shape enables lower voltage needed to cause the spark and results in great ignitability without increasing the size of the spark gap. (excluding IUF27A, IUF31A, IU24A and IU31A)

Insulator Projection

The projection of the insulator is optimally designed based on each plug’s thermal value. This corresponds to requirements unique to thermal value, such as self-cleaning ability at lower thermal values, and heat resistance at higher thermal values. (For all plug types)

Improved Ignitability

With DENSO’s very own U-Groove ground electrode for better spark performance.

To increase ignitability, the important point is to let the flamekernel caused by the spark to grow to a large size. Normally, this can be accomplishing by widening the spark gap, however this causes spark voltage to increase, which has the opposite effect. IRIDIUM POWER uses DENSO very own U-Groove ground electrode to realize a superb ignitability while maintaining spark voltage at low levels.

Improved Horse Power (1)

Get more power with an optimal fuel cycle.

IRIDIUM POWER has a low required voltage and a high ignitability, resulting in less misfiring and no spark, the outcomebeing a dramatic improvement in combustion. Engine output is thus increased. The findings of a bench test using a motocycle engine to show the improved combustion from IRIDIUM POWER is shown on the below. Compared to normal plugs, a 0.5ps (1.4%) improvement is seen in output at 110 km/h.

Improved Acceleration

Increased response and acceleration performance.

IRIDIUM POWER best demonstrates its performance improvement during acceleration.
IRIDIUM POWER has a 0.4 mm diameter iridium center electrode and a specially shaped ground electrode. These features combine to achieve higher ignitability and require lower spark voltage than ever before. This enables high-response driving with fewer misfies than under higher required voltage spark conditions, and fewer misfies when ignitability is difficult. As a result, acceleration improves in comparison with normal plugs.

Improved Horse Power (2)

The 0.4mm center electrode increases output under various driving conditions.

The power produced by the 0.4mm dia. iridium center electrode is IRIDIUM POWER unmatched by other plugs. The graph below compares the resulting power when IRIDIUM POWER is installed compared to other high performance plugs. Using a 0.4mm dia. fine center electode, there is more power compared to 0.8mm and 2.5 mm diameter. plugs. This is what makes the difference in acceleration and in your lap time.

Improved Fuel Mileage

Even during idling ignition is assured, with less fuel consumption.

The good ignitability from the fine electode (0.4 mm) of IRIDIUM POWER draws out much more performance from the engine. Comparing a normal plug (W20FS-U) with an IRIDIUM POWER (IWF22) on a 2-cycle 50cc engine, fuel consumption improved from 41.74 km/L → 43.69 km/L, an improvement of about 5%.

Note: Mileage measured using a chassis dynamo; actual driving results under normal conditions may vary.

Actual products may differ from images shown.