Are Iridium spark plugs worth it?

All spark plugs are copper. "Regular" plugs are plated with a nickel alloy. Iridium plugs simply add a little nib of material that is resistant to erosion from the spark. If an engine misfires it's not because of the iridium. The reason Toyota doesn't install iridium plugs is cost. Let's guess that at volume Toyota pays $2/plug or $12/truck more for iridium. In 2019 Toyota sold 261,346 Tacomas. By installing cheaper plugs they saved $3.1 million dollars. As an added bonus their dealerships now have a steady stream of service customers every 30K miles. Win for Toyota, win for dealers, lose for consumers.

 

My understanding is they use iridium in the 3rd gens which also extends the life of the plug. After 100k in my last truck, the iridium plugs looks brand new with factory gaps, minus the obvious discoloration from being used, of course.

 

It's not a cost thing. As iridium plugs have become the industry standard since the late 2000's. Anything they install on a vehicle as far as cost goes gets passed onto the end consumer anyways.

With saying that, I could see it more as a "returning maintenance" sort of thing, however.

As for all the other comments, it is entirely possible that the reason for all the reported poor running conditions post install and reported misfires may have to do with fake iridium's being installed. That may be what it is entirely.

 

Platinum and Iridium plugs perform at a lower level than copper spark plugs, because they are less conductive and they tend to overheat. However, the overall longevity of these two types of metal is better than copper plugs. In reality, copper has the best performance of all three and the worst longevity.

 

To put that statement to the test I'm going to throw a post up on my blower thread and have one of the boys be a test guinea pig. I'll have them run a set of coppers as their next set of plugs and then switch to iridium's and take a log for each run post install to see how much timing can be given/ pulled and also monitor the knock production between each. If there is no change, the statement is false, if there is a change in favor of either the copper or the iridium then the statement holds true.

 

I run oem Densos. I don’t love the idea of the longer change intervals on iridiums. I feel like it’s asking for a seized plug down the line, I’d rather just change them alittle more frequently.

 

Yeah but their not going to take the time to pull the sc twice just for plugs. Iridium plugs generally run colder than copper. You want a colder plug because the super charger produces hotter cylinder temps which iridium plugs minimizes detonation. Copper plugs can go longer. I went 60K on the originals. No change in performance. Changing the plugs is cheap and easy. Plus it gives me a chance to look other things over while I do it.

 

Who said anything about pulling plugs? The majority of my guys are able to do the plug swap in an hour or less and we do what we do for the sake of data and engine optimization. So we do this in the name of science not just for fun. If there is a better/ faster running condition to be had then it is worth the time invested.

I've done some decent research on copper vs iridium and found no differences outside of longevity in favor of the iridium's. They are both copper cored so there is not much more to be had. I even ran some in my blower and found no difference in performance and spark production/ knock production or lack thereof. I didn't log it, but I found no running differences outside of a smoother idle on the iridium's. So to put these statements to the test is why I propose posting up about this and seeing if someone will volunteer to be test pig. Since plugs are cheap enough anyway.

 

What kind of blower are we talking about here? Leaf blower or something? I’m serious, I have no clue on what blower you use to run spark plug test.

 

Haha.

The Magnuson/ TRD supercharger (AKA blower).

 

I actually enjoy changing the plugs in the 4.0 so I have a strong preference for copper plugs. I even change them every 30k.

 

Not all costs are passed onto the buyer, sometimes they come out of profits. Toyota has to worry about the price Ford, Nissan, and GM are charging for their trucks too. Sometimes a savings is an increase in profit. Because get serious outside of this forum how many people know what kind of spark plug is in their engine? How many even know what a spark plug is?

The plugs length determines its heat.


All automotive spark plugs have a built in resistor. That resistor and a tiny nib of iridium is beyond insignificant when compared to 50Kv coming from the coil.

Yes SCIENCE! Do it. Do it.

 

That’s a conspiracy theory!

 

lol I know, I know. Economics 101 damn capitalism. At one gig I worked for a big, big manufacturer. One part of our bonus was based on lowering the cost of manufacturing. Those savings made for some nice year end pay checks. But if we didn't make the savings or something went wrong the extra cost was not passed on, because we had competitors. Damn capitalism!

 

Iridium tipped plugs don't have a specific quality to make them run colder. As seen above, heat range isn't determined by the material type, but length of the insulator nose.

I have no idea why others have had issues with Iridiums other than the guesses above about being fake plugs OR if they purchased the incorrect heat range. Installing a colder plug will result in some definite ignition problems.