[scoobydoo]

Whether it is time to replace your worn out plugs or thinking of getting a little more efficiency from your stock engine setup or just reading/listening to other riders talk about better accelerations by using better spark plugs, the information below would be of much value


These are what the manufacturers says…

What's all the fuzz about iridium plugs?

What is Iridium?
Iridium is a precious, silver-white metal and one of the densest materials found on earth.
The natural properties of Iridium offered NGK the opportunity to create one of the world's finest spark plugs. The result are spark plugs that require less voltage to spark, burns fuel more efficiently, sparks at leaner air/fuel mixtures, and delivers higher horsepower and better gas mileage.
The fine electrode tip is engineered for greater ignitability. And it's in the design of the iridium tip that makes Iridium IX a better spark plug.
The electrode is not too thin and not too thick. It's just the right size to reduce the voltage required for spark and to maximize the overall longer life qualities of iridium.

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.

Why use iridium plugs?

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. 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.

Who are the major makers?

Main makes in Singapore…
Denso…
NGK…
OWS…

Others…
Volker… German
http://www.volker-iridium.com/images/volker%20pack1.jpg
Torch Iridium spark plugs… China
http://upload.ecvv.com/upload/Produc...park_plugs.jpg
Wanbaolong Iridium spark plugs 070D… China
http://img.alibaba.com/photo/5209611..._Plug_070D.jpg

Which to choose?

Be it Denso, NGK or OWS, each has got their own group of supporters. Manufacturers have their claims and users have their preferences.
It is very much a matter of personal preference, but get the real thing! There’s rumours that “imitations” (claimed to be OEM) are also in the market.
Going by budget (from quotes I got in Jun 2008), NGK is more economical, followed by Denso and then OWS.
My personal preference is for Denso or NGK. Have considered the twin iridium tipped OWS but dropped the idea after reading some scary feedbacks from other riders using them.
Definitely wouldn’t even think about other makes to be on the safe side.

Here’s the results of a poll made http://www.singaporebikes.com/forums...lts&pollid=800
Some feedbacks… OWS & Hodaka iridium spark plugs broke inside engine
http://www.singaporebikes.com/forums...&postcount=487
http://www.singaporebikes.com/forums...&postcount=519
http://www.singaporebikes.com/forums...&postcount=521
http://www.singaporebikes.com/forums...ark+plug+broke

Q5. Which Iridium plugs are better? NGK Iridium IX or Denso Iridium Power?
A5. That really depends on what you want from your plugs. Denso's Iridium Power reputedly offer the best performance but have a shorter service life than NGK's Iridium IX.

What plugs does Honda Silver Wing uses?

Honda Silver Wing FJS 400 (Euro) owner's manual indicated that we can use the following spark plugs:
__ Denso:U22FER-9, U24FER-9 (IUH-24 / 24D not stated but cross referenced)
__ NGK: CR7EH-9,CR8EH-9 (CR8EHIX-9 not stated but cross referenced)
To find out more about what these codes mean, read Design Symbols for Spark Plugs

Where to buy and how much?

Parts suppliers (e.g. FJT, 219, etc), all major motorshops (Looi’s, Mah, ASP, HKL, etc) and the all famous LAB carries but prices will vary from $15 to $20+ each, depending on your bargaining skills and whether installation included.
Motoworld quoted $40 (2x IUH24) including installation so I went to LAB and got them for $30, DIY and saved $10.

When to change (service life)?

Denso = 30,000 miles or 50,000 km
NGK = 50,000 miles or 80,000 km
OWS = 200,000 miles or 320,000 km

Q. How long will Iridium Last?
A. 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.

Q6. How long should my spark plugs last?
A6. That is dependant on the application and condition of the engine. High revving engines, driven hard, (eg motorcycles) will wear plugs much more quickly than a large engined car which is used for cruising. Standard copper plugs usually have an estimated service life of 10,000 to 20,000 miles depending upon design and application, Denso recommend changing their Iridium Power plugs before the maximum 30,000 miles, NGK's Iridium IX may last up to 60,000 miles in a standard use car engine. Double platinum types may last 60,000 miles or more and some NGK and Denso OEM Iridium types may last up to 120,000 miles. The plugs optimum performance level is passed a long time before these intervals so we would recommend changing plugs regularly as a matter of course. An engine, ignition or carburation/injection fault or poor adjustment may cause premature wear and/or failure. Tuned engines, engines driven hard, poor quality fuel amongst other factors can all dramatically reduce service life.

How to change?

Most convenient… most motor-shops will sell their plugs with installation.
DIY… see http://silverwing.org/cgi-bin/topic_...14325#pid14325

Acknowledgement:
Information is compiled from many articles in the Internet, including Denso and NGK manufacturers' websites