'Factory' high performance spark plugs

[GoldOxide_imp]

Found these plugs- made by NGK and appear to only be sold in Japan.

Just ordered a set.

The pictures- although I only read english- appear to show claimed fuel access to the spark area- and increase in flame propagation once lit.

It also appears they show increased fuel economy and power output.

I'll leave it to others to test MPG- but I will be able to test power on my dyno.


Stock plug-







Performance plug-





















NOTE- that they *look* very similar to these, other than the solid non removable terminal below- but if you look close- these still have the square style as opposed to the D shape-


https://www.ngk.com/ngk-90992-silmar8a9s...spark-plug

The "marketing" format kinda reminds of years long ago when one chromium cassette tape manufacturer would butt heads against another chromium tape how their product produced 0.5 dB more headroom with 0.8% less distortion at a given input level and frequency across the audio spectrum.