I replaced the spark plugs today after about 13k miles. The old plugs look a bit rough, see link for trailing plugs, http://www.putfile.com/pic.php?img=4607101 and leading plugs, http://www.putfile.com/pic.php?img=4607100
My question is , do these spark plugs look normal for 13k miles?
I replaced the plugs with NGk RE9B -T and RE7C -L.

 

They still look good!

 

What type of driving do you do. Short 10min runs or hours in trafic? Also what grade of gas reg-mid-prem? How has your oil consumtion been and miles per gal?

 

a lot of carbon, need to red line it more often

 

those look pretty rough to me

 

Ja, running pretty rich. Need more zoom zoom.

 

well you were running without a front O2 sensor for a while, this kept the system open loop all the time which is way rich for typical street driving

 

those plugs does NOT look good to me. U need to run it harder. crap.

 

What type of leading plugs are those?? They are the old style plugs......there should be updated ones for the leading..........

 

unless you are into freq "messing/cleaning the plugs every 5K or so " , for 13K mile sparkplugs, stock (basically), set up they look "normal" too me. Normal doesnt mean good/ok here. And like others have said--get the updated plugs.
olddragger

 

Thanks for the comments guys. I do a lot of very mixed driving. i.e. city and long haul (250+ miles trips). I track day the car only about 4/5 times a year. I wouldn't molly coddle my car as I believe a bit of spirited driving is all part of owning an RX8, but I do need my driving licence for my occupation so when in the city limits I do try to stick to the speed limits. This has to be the hardest thing to do with such a smooth and lively car.
These plugs including the RE8A have been in the car from the beginning. The car has been serviced according to the Mazda manual (says the Mazda dealer?). I don't trust the Mazda dealership here in Ireland. I doubt they have carried out any proper maintenance on this or any Mazda car they are responsible for. The Mazda dealer has also said that the car would have received all PCM updates at these services?? This is something I cannot substantiate because I don't know which flash/s should be applied here in Europe? TeamRX8 is correct that my front O2 sensor was not functioning properly but that was for about a 1k miles maybe.
I now get a private motor mechanic who is also a motor sport enthusiast http://www.tuningfactory.ie/ to do my maintenance, this has proven to be a better way of getting proper maintenance and at a lower cost to me. My mechanic thinks that the RE8A's needed replacing with a slightly hotter spark plug and with that in mind I have replaced them with the RE7C. I think his reasoning seems sound and hopefully that heavy carbon build-up will be eliminated.

I forgot to mention that gas/petrol in Ireland comes in only one octane -95octane. We used to have 95 and 98 octane but the 98 has all but disappeared from the forecourts. The 95octane is what is recommended for the RX8 here. I have also just recently switched to a full synthetic motor oil i.e. Motul 5w30w

 

I'd say you should be fine with the re7's. That is the standard heat-range for this engine. Not sure why you were running 8's?