NGK SPARK PLUG TUNED ROAD ENGINES

A higher compression engine should have a colder spark plug. The engineers explain that it has to do with flame temperature and overheating the plug. I know from experience that my race engine will melt a street plug. Choose from the following NGK plugs: Cold Street=BP7ES For CR of 10 to 11:1 Colder Street=BP8ES CR of 10.5 to 11.5 Cold Race=BP9EV CR of 10.5 to 12 Coldest Race=BP10EV