Plugs & Higher Octane is a lot simpler(and quieter) than the CAI option. The Jacksons have spent a lot of time & dollars on research & testing.

 

Any car nowadays with a knock sensor and enough programming to read it properly can benefit from higher octane and colder plugs.


Also, colder plugs do NOT reduce horsepower


However, while testing higher octane with plugs, I discovered I bounce off the 55 degree advance cap all the time on 93, but happens less often with 91.


On 87, I barely ever touch 55 degrees advance. Only on light load light throttle conditions

 

Fixed it for ya.

Not just that but I've found their prices on the higher side, other sites like Kami, Bean, etc., have much better prices. They (pwjdm) never got my business before and they sure won't get it now.... kinda reminiscent of the Junk2 (hitman for hire) fiasco a while back. ahahaha...

I've been regularly using 93 for a while now... I'm happy with the results. Plan on changing to one step colder plugs in the spring. IIRC, 555 has 2 step colder plugs on his JDM RS, but he also has the JDM J's Racing Hyper ECU. I think a few other people in warmer climates are also running 2 step colder plugs with good results.

 

AH plug heat range is NOT affected by outside ambient temperature makes no difference what the air temp is.

And two steps on an ordinary stock Fit may be too cold and cause fouling with no extra benefit.

 

I'll just sit here and