Off the NGK website:

Iridium Spark Plugs

Iridium is a precious, silver-white metal and one of the densest materials found on earth. The natural properties of Iridium offered NGK the opportunity to create one of the world's finest spark plugs. The result are spark plugs that require less voltage to spark, burns fuel more efficiently, sparks at leaner air/fuel mixtures, and delivers higher horsepower and better gas mileage


In theory these plugs tax the ign system less than regular plugs right?
I wonder if running iridiums will extend the life of an OPTI? ? ?


I'm running an MSD unit and iridiums. I'd like to hear from those who are running these plugs or if you have a theory about this too.

 

I just replaced mine after about 50-60k miles. They still looked good, were obvously worn, but were still fine. Probably shouldn't have let them go that long though.

 

Go with copper if you don't mind changing plugs a bit more often. Copper is the better conductor and run less than a buck each. Plats and Irradiums are harder and supposedly last longer, however, I heard tell that the Delco Plats, stockers, were damn near puckless with fewer than 50 grand on the clock---supposedly to last twice that long. JMHO

 

I pulled out a set of ACD platinum/iridiums (I cant remember now) that appeared to be OEM... never changed. Still had the factory paint marks on them... looked like they got tagged with a paint pen lol. Replaced them when I got the car... looked worn, but still totally functional at around 100k miles.

 

Iridium isstrictly about reducd gap erosion. The MSD ignition stands to do more needless damage to the opti than you can even dream of the iridium plugs helping avoid. Ignition upgrades are NOT necessary on these cars till pretty heavily modified.

 

^ I'm running an MSD opti. Coil's stock and just about everything else. 177K and still running hella strong.

 

Well the MSD opti is not so good either.

 

You'll have to qualify that statement with some facts bro otherwise it's just a plain old opinion.


This opti's got well over 50k and still going. I've accidently spewed coolant on it more than once whilst dealing with the tstat and can't seem to kill it.

The whole point of this thread is that if you run Iridiums, the life of your opti will be extended - that is my premise. I hope someone can disprove this statement with factual data.

 

If you want facts just do a search for MSD opti. And it's very doubtful that anyone has conducted such research, so people like you and me have to rely on the experiences of others. Probably half of the people who have used the MSD opti have had issues with it, including myself and my brother. AC Delco for me from here on out.

 

I have doused several stock optis between my three LT1 cars I have put around 200K on, and have a current combined milage of over 500K. Trust me, I know what keeps an LT1 running.

 

The iridiums might fire at a lower voltage and they also might retain the correct gap for longer so it's possible that they are slightly easier on secondary ignition components like coil, wires and distributor. Not sure if it is a measureable difference when you consider custom engines like we have.

 

I really doubt that plug core has a significant impact on opti life.