Iridium Plugs

[Fifty150hs]

Anyone else try or use Iridium plugs? I put some in about 36,000 miles ago. I did so based on claims by some of improved fuel economy. I saw no improvement at all. I pulled the plugs today to check and see how they were doing. I checked the gap. They had all consistently opened up .020 inches. IN 36,000 miles?! I'm thinking I'll put the four pronged plugs in. These plugs don't seem to hold up or provide any mileage benefit. Thoughts?

[crystalworks]

I have exclusively used ngk iridiums on my BMW's (~15 of them now). Won't put anything else in. Never had any running issues and didn't have to change any of them at an unreasonable interval. Excepting my self tuned turbo car. That needed new iridiums every 20k miles.

Not sure why yours are opening up? They look kinda dirty...

[andrewwynn]

I’m a fan of the oem NGK. My mechanic put in some champion plugs that lasted less than 25,000 miles where the OE lasted 115,000.

I was getting cylinder misfires when led me to pull a plug and it was gross.

[Purplefade]

I’m with CW, I’ve used iridiums in everything I drive and have never had an issue other than one premature porcelain breakage... and there’s 5 drivers in my household.

I guess it’s possible that you got a bad run of plugs maybe... dunno, but definitely odd.


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[StephenVA]

Center electrode rapid wear is caused by heavy loads and lots of WOT. Plug life for precious metal plugs is any where from 45-150k depending on drive cycles and driver throttle inputs.
I have these same plugs in 5 vehicles without any premature wear.
Yours show lots of fuel additive spots and some mixed heat temps. What type of gas do you run? Brand and octane levels?

[Overboost]

Originally Posted by StephenVA

Yours show lots of fuel additive spots and some mixed heat temps. What type of gas do you run? Brand and octane levels?

Agreed, looks like detonation peppering on the plugs from heavy load and regular 87 octane fuel.

[StephenVA]

Can't tell on the detonations as it takes a little better image or a 8X lupe
Send me the plugs and I will tell him. Lots of short trips if with poor gas but that is a guess (SWAG) without holding the plugs
Anyone want to guess that this one is running cold. Love to see the plugs after a 3000rpm buzz down the hwy for 50 miles as these plugs never burned off all the trash on them.

[Mouse]

Same as Crystalworks as well. All I use and only had accelerated wear on my modified turbo car. (Which is normal) I, however, do change my plugs out much earlier than recommended as cost and labor are usually cheaper and easier than a oil change so....why not.

And you can call me a sucker, but I only run premium fuel.

[StephenVA]

Trailer towing? Cheapest Cal gas one can find?

[Fifty150hs]

Originally Posted by Mouse

Same as Crystalworks as well. All I use and only had accelerated wear on my modified turbo car. (Which is normal) I, however, do change my plugs out much earlier than recommended as cost and labor are usually cheaper and easier than a oil change so....why not.

And you can call me a sucker, but I only run premium fuel.

Then I'm a sucker too. I only run premium. I'm not interested in risking a burnt valve.

Other than the melted electrodes, I have seen no difference in performance or fuel economy between the iridium single electrode and the standard four electrode plugs.