Pulled the plugs this weekend ...

[Need4Speed]

Pulled the plugs this weekend and just wanted a second opinion.

Mods include Cobb SRI+TIP, Test Pipe, mild tune ... nothing serious.

I was experiencing some WOT stutter and when I pulled the IC off I noticed that recirc line from the BPV had a leak. The OEM clamp had eaten it's way through the hose and basically severed it from the nipple. Replaced the plugs and fixed the hose and car drives like a champ again. Could I stand to go to a colder plug? Looks like the plugs are very clean looking, chalky white, clean insulator. I didn't notice a lot of pitting, but one of the plugs did exhibit a small amount. My inclination is to say they are running a bit on the hot side.

pix of plugs
http://dl.dropbox.com/u/3623939/IMG_3105.JPG
http://dl.dropbox.com/u/3623939/IMG_3106.JPG
http://dl.dropbox.com/u/3623939/IMG_3107.JPG

I find it odd that the standard MZ3 engine calls for the same plug as the MZ3 Turbo ... and the MZ3 Turbo puts out nearly twice the power. If it's spec'ed correctly for the non turbo then it has to be on the hot side for the turbo. If it's spec'ed correctly for the turbo then it has to be too cold for the non turbo. Can't be right for both applications IMHO

 

[overst33r]

http://www.dansmc.com/spark_plugs/spark_plugs_catalog.html

Maybe that will help.

 

[JCH13]

Many MS3 guys run 1step colder and swear by it, FWIW.

 

[Eli]

Those plugs are definitely running a bit too hot, either from a lean AFR or just not being the correct heat range.

 

[Need4Speed]

Thanks for confirming my suspicion. I thought so as well, and the chart that mariok2006 posted also seems to indicate that. I am going to install a step colder and check them again in a few weeks. There does seem to be some discrepancy depending on who you ask or what charts you look at. The Denso Chart could be interpreted as my plugs being normal:

http://www.densoaftermarket.com/downloads/downloads/55/DENSO%20Diagnostic Poster - SP.jpg

But that insulator is more on the brown/tan side than mine. Mine is stark white with some gray.

 

[JCH13]

Thanks for confirming my suspicion. I thought so as well, and the chart that mariok2006 posted also seems to indicate that. I am going to install a step colder and check them again in a few weeks. There does seem to be some discrepancy depending on who you ask or what charts you look at. The Denso Chart could be interpreted as my plugs being normal:

http://www.densoaftermarket.com/downloads/downloads/55/DENSO Diagnostic Poster - SP.jpg

But that insulator is more on the brown/tan side than mine. Mine is stark white with some gray.

Notice the very slight amount of black carbon buildup on the "normal" plugs vs the lighter gray on the "overheated". I think that's the only perceptible difference in their chart, very subtle.

 

[Eli]

The giveaway is the bright white center ceramic. It should have a slight grey tint to it.