NGK's advice for MSP
I asked NGK about the plugs in our cars and if a copper plug was better for a turbo application. Specifically asked about PZFR6F vs BKR7E.
Here is what they said.
"Hello,
All NGK Spark Plugs are copper core. It's the firing end design that's different. Remember NGK engineers work closely with Mazda engineers to produce a spark plug that's best suited for the application. The reason they use the fine wire platinum design are as follows.
1. Lower voltage required to fire the spark plug. Improves ignition
efficiency.
2. Longer service life
3. Enhanced ignitability
4. Lower emissions
5. Less quenching
6. better anti fouling
The BKR7E is a nickel alloy spark plug and will wear very quickly. You won't obtain a complete burn of the A/F mixture as with the double platinum series. In addition to this the PZFR is an extended projected design. This means the A/F mixture will be ignited towards the center of the combustion chamber. This means stable idle and improved combustion. If you use the nickel spark plug the ZFR series is a better choice. I would highly recommend using the new iridium IX series. BKR7EIX if you need cooler spark
plugs.
