Ruthenium?

2016 Mazda CX5 owners manual recommends spark plug replacement based on mileage. OEM plugs are NGK  iridium.  I have used NGK since the 60s in every car/truck I have driven. Went to RA to check on availability/price and found NGK ruthenium as an option. Any experience/feedback on ruthenium vs iridium? Thanks

Ruthenium? I only use niobium, personally. /sarcasm

In my experience, OEM NGK Laser Iridium plugs routinely last 100k miles. I wouldn't hesitate to throw in another set of those and not think about it again for another several years.

I'd use whatever OE spec was.  Spark plugs can cause weird issues you wouldn't think were really possible, just from going from copper to platinum to whathaveyou.

When the industry went to fine wire electrodes they had to start making them out of precious metal to get any kind of life out of them.  Since precious metal is expensive manufacturers are constantly coming out with different alloys to reduce cost as the metals market changes. From a performance standpoint they're all the same.  From a plug life standpoint they're all pretty similar as well.  Some alloys hold up slightly better than others but the difference is marginal and is typically less than the difference from one engine to another.

Maybe that's why the various heat ranges we used to obsess over have gone away?  I'm just an old fuddy duddy  who hasn't kept up?   So find out what Champion and NGK recommend for my V12? 

frenchyd said:

Maybe that's why the various heat ranges we used to obsess over have gone away?  I'm just an old fuddy duddy  who hasn't kept up?   So find out what Champion and NGK recommend for my V12? 

Modern fuel injection and ignition systems are pretty smart and the different heat ranges aren't needed.  The exceptions are still around, but mostly centered around extreme cases that most will not see (unless you drive on the North Pole, etc.).

Older rigs and engine designs, etc. can still benefit from different heat ranges, depending on their use and fuel type.

I had to buy non-resistor spark plugs for one of my bikes last month.

That was an adventure.

Heat range is strictly a rating of how quickly the plug can dissipate heat.  It has nothing to do with spark energy or spark temperature.  The plug gets hot from the combustion process and needs to cool down before the next intake cycle or it will ignite the incoming air/fuel mixture as soon as it reaches the plug.  That condition is called pre-ignition.  On most engines the mixture reaches the plug while the piston is still coming down on the intake stroke.  As you can imagine trying to compress the mixture while it's burning doesn't work all that well.  That's what creates the characteristic hole in the middle of the piston.  Thermal runaway that results in the piston participating in the combustion event.

When leaded gasoline was a thing it was necessary to run the plug hot that deposits wouldn't form on it, or at least would form slowly, but not so hot that pre-ignition was an issue.  Oil control, the oils themselves and poor mixture control also contributed to the formation of deposits or, fouling as the condition is known.

With unleaded fuel, modern fuel injection with its precise mixture control and modern oil and oil control fouling is much less of a problem and the window between pre-ignition and plug fouling is significantly wider.  That's why an NGK 8 or 9 works in most modern cars.

That window and what can go wrong when you're outside of it is why I recommend starting with a colder plug when making any significant changes from stock.  Sure, you might foul a set of plugs or two while you dial things in but you can buy a lot of plugs before you get to the price of even one piston.

Stefan (Forum Supporter) said:

frenchyd said:

Maybe that's why the various heat ranges we used to obsess over have gone away?  I'm just an old fuddy duddy  who hasn't kept up?   So find out what Champion and NGK recommend for my V12? 

Modern fuel injection and ignition systems are pretty smart and the different heat ranges aren't needed.  The exceptions are still around, but mostly centered around extreme cases that most will not see (unless you drive on the North Pole, etc.).

Older rigs and engine designs, etc. can still benefit from different heat ranges, depending on their use and fuel type.

I'm not sure what you guys are talking about; as far as I know, running the correct heat range plugs is very much still a thing.

Stefan (Forum Supporter) said:

frenchyd said:

Maybe that's why the various heat ranges we used to obsess over have gone away?  I'm just an old fuddy duddy  who hasn't kept up?   So find out what Champion and NGK recommend for my V12? 

Modern fuel injection and ignition systems are pretty smart and the different heat ranges aren't needed.  The exceptions are still around, but mostly centered around extreme cases that most will not see (unless you drive on the North Pole, etc.).

Older rigs and engine designs, etc. can still benefit from different heat ranges, depending on their use and fuel type.

Problem is the EFI was anything but modern. In fact it was one of the very earliest ones. Extremely crude. In fact the first years were all batch fired. Plus back at the ECM there is a knob to dial to lean or richen the mixture. ( later eliminated). It has no way of adjusting the mixture. Any change requires various foods, transistors etc being soldered and unsoldered.   
No OBD2  in fact only the last few years had anything but analog.  
    The ignition is a twirly distributor.  Timing is adjusted by timing light and moving the distributor. 

Ruthenium is primarily used for hardening electrical components in high wear contacts.  Does it maybe last longer in an electrode where punishing cylinder conditions might exist?