NGK (4660) R7433-9

Aparently this is the plug used in the hrc kit. Has anyone ever used these? Says it has a fine iridium center. I know everyone has different preferences but do iridium plugs really make that big of a difference?

searcher415, on 13 February 2012 - 10:42 AM, said:

Not one you're likely to feel on a 50hp engine. Iridium fine wire plugs' biggest benefits are long life and resistance to deposit formation. Additionally, the smaller electrode requires less voltage to make a spark jump the gap than a regular plug under equivalent conditions. When iridium plugs hit the widespread consumer market about 15 years ago, the biggest (and still not very large) gains were seen with highly boosted engines already making a lot of power.

At almost $40 for one plug, it better buy me dinner as well as give an extra 10 horsepower.

http://www.amazon.co...g/dp/B002FUOFKE

Agent2, on 14 February 2012 - 08:14 PM, said:

Yeah definitely. I don't see how a plug can be worth 4 times than one that does the same thing. I'm assumed this was just a marketing sceme that involved the word "racing" but i wanted to see if anyone had any first hand experience.

That's good to know about highly boosted engines. I'm sure there's some science to go behind it.

Wow, I though iridium plugs topped out around $10/ea these days.

searcher415, on 15 February 2012 - 06:49 PM, said:

There is. High boost is usually associated with high charge density. High charge density means more dielectric fuel in the plug gap to keep a spark from jumping. Pointy electrodes make it easier for voltage to jump that gap.

I know I've tried them in my various bikes and still have them in a few bikes but can't tell any diff between using them and a normal plug.

Apart from being irridium it's one step colder than a stocker,that's it's reason for being actually.