Originally Posted by Element Tuning
Now, the million dollar question is did you reduce power with the colder spark plugs and therefore engine noise was reduced or did you reduce some low level detonation with a colder spark plug due to controlling the temperature of the insulator? Unfortunately that answer will be in the dyno plot when you put your car on the dyno and test it
Thanks Phil. That makes sense.
Given a total
lack of change in original (high) knock threshold levels when going from 93 to GT100 on the hr7 plugs, I would have to say the former -- reduced power going to hr8, and they're likely unnecessary.
This is where you say, "Well if you experienced that lack of voltage change, why did you put hr8 plugs in?" Because?
I'm paranoid? I don't know.
As an aside, having seen my buddy's hr7 plugs from his "TXS Stage 4 WRX"-like setup, they seem pretty unnecessary there.