I have denso iridiums in my B18C integra now for over 18 months, so about 20k+ miles (not exactly sure) I've been reading through archives with some members saying they only last 6 months. According to denso they have a 100,000mile life although i'd never leave them in that long. Does anyone know or has anyone found them to loose performance after XXX miles, or how long has everyone using them had the same set in. I found i gained 50 miles to a tank after fitting them, i swapped in stock NGKs a few months back and tried them for a few weeks, doing the same mileage in the same driving conditions and could only manage 250-260 max to a tank of gas, i put the iridiums back in and have been getting approx 300-310 miles per tank ever since. I've been using Blitz 9mm plug leads with them for approx 6 months and dont know if they would effect the life of the plugs or not, anyone got any definite ideas/knowledge on the iridiums life etc???

 

they will realistically last over 75,000 miles. unless you have some seriously harsh conditions. just pull them out and clean them with brake cleaner

 

i was thinking about doing that, but didnt know if carb/brake cleaner would be too harsh or them. i havent found any loss in performance/MPG with them, i was just wondering if it was time to replace them. i'd definitely get another set without a doubt!