For my technical friends here at Corvette Guru. Are Iridium plugs worth the extra price?

I'm changing plugs in my MX-5 Miata and factory calls for platinum plugs but lots of people on the Miata forums seem to be spending $$$ to buy the iridium plugs. I bought some basic 3year Autolite Platinum plugs for $10 for all four.
Iridium plugs are at least $8 each. Are they worth the Xtra cash?

IMO - No. But then I am no expert.

I'd stick with the factory plugs, but that's jus me .

The thinking behind the iridium plug is that the spark is much more focused. this is supposed to improve the light off of the charge.

The only thing... iridium plugs don't last as long.

I have used them, can't say I noticed any difference. In short, a good platinum plug will do just fine. I still like NGK platinums.

personnally, all these super duper plug designs these days, like E3 and split fire, etc, are just ways of parting you from your cash.

The E3 folks claimed a hp gain from their plugs, so they ran this motor on a dyno, got a number, put E3's in and it picked up power! I suspect any new plug would have made the same improvement.

Good spark plugs are worth 1 HP per dollar so, a $20 lpug will give you 20 more horse.

Quote:

Years back I did dragstrip back to back spark plug tests with multiple different plugs....for my application, as long as you had the right temp spark plug for your engine, I couldn't detect a difference on the timeslip.

I will say, if you have old plugs, I did notice a slight difference just going to a new plug. (any new plug) I had 20,000 mile plugs twice, both times, new plugs found me a few hundredths.... which isn't much, but it was detectable on the slip.