Iridium Plugs

[Hib Halverson]

Originally Posted by Rodder

Be aware of counterfeit NGK and Denso spark plugs when shopping on the internet. Try google fake spark plugs. Use an authorized dealer so you know what you getting.

Used FR1LS 035 and now Ngk bkr7e-11 044. Never logged to compare but runs fine with both and my driving style.


Thomas

"Rodder" is correct. There are a lot of fake NGK and Denso plugs sold on the Internet. Solution: buy NGK and Denso from legit retailers of those brands.

[Paul Workman]

Yep! Hib is correct about "hotter vs. colder" spark plug rating. But, far as the arc itself goes, it is true too that the amount of GAP will affect the voltage necessary before current will jump the gap, and the resistance combination of the plug wires and plug's internal resistor (if any) will affect the follow-on current (heat) of the arc itself.

The diagram* is a little confusing. Heat range of the chamber and heat (type) of the corresponding spark plug are opposite. Chamber temperature range increases with engine load and RPM. So, low speeds and low power demands = low chamber temps which require a hotter plug to burn off fouling, and visa versa.

See attached from Denso site:

*Just about any of us could have selected better (less confusing) descriptions, me thinks. Just remember low speed, low performance demand = need for HOT plugs to keep from fouling, and visa versa!