So $140 and a new spark plug socket later, I replaced my original plugs with the updated set which includes the redesigned leading plugs. The trailing plugs are the same. These are not the hotter plugs that are also available, but a redesigned plug rated at a 7. The overall install wasn’t to tough, I took the wheel off and could get at all them through the wheel well. They came out without issue, and I hit them with some anti-sieze as well as some dielectric gel on the way back in.

I have 11,200mi on my car and my reason for the change “early” as my idle has been rather rough and I wanted to see what it would do. It has seemed to improve the shudder feeling I get at idle every few seconds, its not gone, but certainly better. As for mileage and power, I’ll have to get back to you guys after a week or so.

The old plugs were not black, they were brown, I will post some pics to show what they look like. I’ve been told that the 30,000mi replacement rule is a little long by most rotorheads, so I think most people should swap out for the new ones by 20,000mi, if for no other reason than the break-in period and multi-flashes for most of us has been hard on our plugs.

Oh, one last thing. The spark plug socket for our car is a 13/16, not a metric! WTF is up with that?

 

Cool...keep us updated!

 

Just curious. Does Mazda claim or imply better power-performance from the new plugs?

 

Why did YOU pay for it ?

 

I paid for b/c the TSB with the new plugs were the hotter plugs, which is not something you want to switch to if your going to drive the car hard. The new leading plugs I installed are the redesigned "7's". Thankfully, with some cleaning, I think I can save the old trailing plugs.

 

What is the stock numbers on the ngk plugs? Thanks

 

The manual says replace at 35,000 miles.

Of interest here, when I was at the dealer yesterday to pickup my car after its 25K free service, I asked my tech about the plugs. He produced a box full of plugs from under his cabinet. I asked what those were. He said that these are all the plugs that he has removed from 8's that have been towed in for flooding issues. He puts in the new hotter plugs, then cleans these up and puts them in a box. He offered me some, so I will most likely take him up on that offer. I'll bet every dealer has a box of plugs just sitting around collecting dust...

 

The new leading NGK's are RE7C-L, the original's are RE7A-L

 

guys i have the hott plugs............the number is ngk-re6a-l for the leading plugs........re7a-l are the org plug number for the leading.......i would not run a rotary without the hot....car performance is much better......because it keeps those plugs burning clean........

 

Sorry Brillo the pictures of your plugs on my phone are not the best.


Old Plugs


Old Plugs


Old Plugs


Old and New Plugs


New Plugs

 

For the looks of those pictures those plugs look just fine, they should be slightly brown as that means good cumbustion is occurring, I would clean them up and use them when the new ones get old, but that might just be me.

 

Do you have a Mazda part number for the new set? My dealer said the new leading plugs (N3Y8-18-110) were only available individually (not in a set with the existing "trailing" plugs). As such, I paid a premium.