NGK Iridium Spark Plugs vs Denso Iridium Power – What is the difference?
First things first, why do you want Denso or NGK iridium spark plugs anyway? They cost 4-5 times more than platinum!
In a word consistency.
Why Is Iridium Better Than Platinum?
The spark gap on platinum spark plugs can grow over time. As the electrode erodes the distance the spark needs to jump between the electrode and the conductor increases and this demands more power from the ignition system. This extra strain can shorten the life of ignition components leading to problems like misfires and having to replace parts.
Iridium electrodes on the other hand, in my experience, erode imperceptibly, even after 100,000 miles the gap can look the same as it did when the spark plugs were new.
Depending on the engine and level of tune, you may have to inspect the spark plugs every 3-6 months to check the spark gap and to regap the plug (with a platinum spark plug) with an iridium plug you do not, again, in my experience.
In short, Iridium spark plugs with their iridium electrode last many times longer than a platinum spark plug, they maintain a much more stable spark gap and they do not require as much attention ie you don’t have to check them so often. Iridium spark plugs last longer and their performance is consistent because the spark gap is more consistent than platinum spark plugs
NGK Iridium IX vs Denso Iridium Power
On to the original question, what is the difference between NGK Iridium spark plugs (IX model of plug) and Denso iridium plugs (Denso Iridium Power model of plug)
Is you butt dyno going to be able to tell the difference between the same engine using platinum spark plugs vs Iridium spark plugs?
No.
Ultimately the difference between the NGK and the Denso comes down to philosophy.
NGK Iridium Spark Plugs
NGK Iridium IX are designed to be a standard replacement spark plug that lasts many times longer than platinum, gives more consistent performance and with less maintenance (less regapping).
Find the code of your NGK spark plugs – Click here
Search with the code & buy on eBay
Denso Iridium Spark Plugs
Denso on the other hand have taken the superior hardness of Iridium and chosen to shrink the diameter of the electrode more than NGK. Because there is less material in the Denso Iridium spark (vs NGK Iridium) plug the life of a Denso Iridium Power spark plug is going to be theoretically less than an NGK iridium plug.
The justification for using the smaller electrode is that it makes creating a spark easier which gives the spark more power, improving fuel economy and power. At least I think this is the spiel given by Denso, if it stacks up in the real world, I don’t know.
Find the code of your Denso Iridium spark plugs here
Search with the code & buy on eBay
Conclusion – NGK Iridium IX vs Denso Iridium Power
In my opinion, if there are any differences between NGK Iridium and Denso Iridium, we are probably talking fractions of a percent but if you are looking to squeeze every last ounce of power out of your engine and you don’t mind paying a bit extra and maybe having a shorter service life than NGK Iridium IX, the Denso Iridium Power spark plugs are probably the choice.
If you don’t care about fractions of a percent in horsepower and you want a plug that will massively outlast and outperform platinum spark plugs, you probably need NGK Iridium IX.
