Ok...This isn't some "What spark plugs to use" post but more of a why Iridium plugs are supposed to be "Better"

A little back ground on the car. I just have a basic Buschur Stage 4 that is Dynoflash'd plus I have the HKS DLI2. Stock turbo pushing no more than 21psi. I have had this setup for over a year without having even 1 issue but lately I started getting backfires at about 18-19psi when I did WOT from low RPM's in 3rd gear and above. It felt like the timing was being pulled drastically and if I lifted off the pedal for 1/2 a sec then WOT again it wouldn't do it. Also this never happens I did a high speed run starting in 1st. At first I thought it was bad gas so I switched companies but still had the issue.

Then I started thinking that maybe I just have a bad or fouled plugs because I run a bit rich. Went down the street to pick some BR7ES but they only had 3 But they did have the BPR8ES so I picked them up. Came home swapped plugs expecting to see the stock plugs all nasty but to my suprise they looked perfect. Put the new plugs and went for a test run. All things fixed now...actually I think it feels better than it did before I was having the issue with the stock plugs.

Iridium plugs are supposed to be the best plugs and I do not see my mods as being so drastic that I would require colder plugs. Could the DLI2 be making such a hot spark to cause a bit of pre-ignition? If so why after 1 year would it start doing it and not right from the start?

Ok lets hear from you spark plug gurus out there. Thanks

 

I run BR7ES's and I have to replace them every 10,000 miles or so. They look perfect when they come out, not fouled or anything. Your not getting pre-ignition on the old plugs, they were just worn out. The Iridium plugs last longer than standard ones, but in turbocharged cars, platnum plugs are a waste of money. They dont have any benifits or increased duribility.

 

That seems like a very reasonable answer. I understand that plugs do wear out....but I only have 11k miles on the Iridium plugs and didn't think they would be giving me troubles so soon. Maybe I was expecting more than I should from them. I certainly expected more than 11k miles. Thanks

 

Higher boost will shorten the life of your spark plugs.

Iridium isn't the best "performance" plug. Copper plug is the best performance spark plug but they need to be changed very frequently (every time you change your oil).

Iridium = Copper-like perfomance with longer life. The cons of iridium is that it is expensive and can come apart (electrode separates) if not manufactured correctedly.

I will not buy Iridium. Would you rather change your spark plug more often or less often? (Think of maintanence)
"Performance"-wise, Copper>Iridium.

Edit:Get NGK BPR7ES

 

did you check the gap after pulling them?