Does anybody know which spark plug runs cooler,is it thePFR6B or the PFR7B,and which set of plugs are the better ones when running higher boost settings,i.e,more power,any help appreciated thanks.
__________________

 

The 7's are colder, I use them on mine with no problems (1.4bar), when you start heading towards the 500 bhp mark they do Racing 8'S aswell