Iridium IX spark plugs: Boosting special engines with a precious metal upgrade

Power for 2-wheels

Recognising particular demand for upgrades from the 2-wheel sector, the company initially launched its Iridium IX technology in 2006, especially for motorcycles.

The goal, explains Kai Wilschrei, Senior Manager Technical Services Aftermarket EMEA at NGK SPARK PLUG EUROPE, was to help riders achieve significantly better performance from their bikes, whether on the road or track. “Motorcycles are often fitted with standard nickel spark plugs as original equipment. But the extreme strength and durability of iridium offers the potential for enhanced ignition reliability and performance. With Iridium IX – short for ‘Iridium IXtreme’ – we were able to give riders improved ignitability that lasted even longer than platinum. They could also enjoy a smoother, more economical riding experience.”
To create the new technology, NGK SPARK PLUG engineers designed an ultra-fine, 0.6mm diameter iridium alloy tip, laser welded onto the plug’s central electrode. Together the slimmer iridium centre electrode and taper-cut ground electrode kept the required ignition voltage low and put less stress on the ignition coil, whilst generating a powerful spark. In addition, the consistent distance maintained between the hard-wearing electrodes avoided misfires. “We also devised an anti-fouling annular gap to make sooting a thing of the past,” continues Wilschrei. “This made cold starts problem-free and gave the best ever performance in stop-start traffic, where motorcycles need to excel.”

A positive side-effect of the innovative material was Iridium’s impact on spark plug lifespan. The expert adds: “Iridium is one of the world’s most durable metals: around six times harder than platinum. Added to its very high melting point of 2,450^oC, it’s extremely resistant to spark erosion. As a result, the lifespan of the iridium electrodes in our IX spark plugs is significantly longer compared to the electrodes of conventional nickel plugs. That’s worth the investment for any rider whose motorcycle isn’t already fitted with original iridium plugs.”

Iridising vintage cars

The benefits of Iridium IX are not restricted to 2-wheels. NGK SPARK PLUG soon expanded the technology to put more power under the bonnet of classic cars too.

“Iridium IX offers an excellent upgrade opportunity for older cars and some younger ones, as well” affirms Kai Wilschrei. “Fitting them as replacement spark plugs assures vintage car drivers of reliable first-time ignition, no misfires and the longest possible service life – with no carbon build-up.”

Wilschrei himself owns a vintage Audi 90 built in 1985, as well as an old scooter. “The first thing I had done after buying the car was to replace the spark plugs with Iridium IX upgrades,” he confirms. “Now the car is much quieter when the engine is idle. Starting performance is also very good. The same goes for my Vespa!”

What riders said

When NGK Iridium IX spark plugs were first launched, more than 230 riders of modern and classic motorcycles tested them out. Here is some of their feedback:

- “The Iridium plug has optimised the running smoothness of my single cylinder.” Rico

- “After five refuelling cycles the plug has already paid for itself. Fuel consumption has dropped to less than five litres per 100 km.” Kirsten

- “The Iridium plug changes driving and response behaviour significantly. What I like most is that the power kick-starts about 1,000 rpm earlier, which is very useful after cornering.” Andre

- “There has been a clear difference to normal spark plugs, especially in winter. Starting behaviour was clearly better and even with a cold engine its smoothness was remarkable.” Othmar