what are the best spark plugs for a 1994 mazda rx-7

 

im sure search will get you a ton of suggestions,

i use four ngk 9's in my car (the copper ones)

I have to replace them every 5k or so.

 

Depends on your level of modification, if lightly modded or stock, the stock NGK 7's and 9's are just fine.

 

Word.


-Dan

 

How about moderately moded. M2 ic, air box, dp, 3" cat, cb, hi 6, pfc, denso fp, street port, alum fly whl, mostly just bolt ons. I am hoping to have it tuned for 14 pounds on the factory twins. It has been suggested to run ngk 10.5 in it.

 

Definetaly use all 9s instead of stock 7s and 9s

and definetaly you don't need 10.5s for that level of modification

no need to search 9s are a colder plug, they are safer when the car is modified, it will run like crap until it is warmed up. Also all 9s do need to be replaced sooner

I suggest using 7s and 9s for slightly modified and 9s if you have a ported motor or all of the bolt ons or a single turbo. I guess those really high powered guys need 10.5s

 

I am fairly modded running 12psi and I went with 9s all around this past spring as a little added insurance with them being a colder plug.

I did a good amount of research on the topic prior to going with 9s all around and it seemed as though when running at a level of boost higher than stock the 9s could be utilized even if you are not highly modded.

I've been running them since the spring and I am happy with my decision.