I have one Slick and one SureFly on my IO-320. Not flying yet, but what are the benefits swapping over the SureFly harness from massive plugs to auto plugs?
You can buy 8 NGK plugs for the price of one Champion.
Working off my inconsistent memory....so check your SureFly docs. I think I recall them stating that even though the SureFly will work with auto plugs they didn't see any advantage to using them.
I called Surefly and the nice Gent I talked to has a RV6 and uses Automotive plugs. He just replaces them every 12 mo condition inspection. It is not about extra performance, however the NGK's perform well. There is a few decades of experience using NGK's in Lycoming's. The reason to go from aircraft plugs to NGK is cost.
So what is better mean? Genuine NGK** Vs. standard Champion REM40E, RHM38E - The Champions are $40 each or $320 for a set of 8. NGK is $24 for a set of 8. So 1/13th the cost. You can afford to replace them every year. We milk our expensive Aircraft plugs with cleaning, testing and reuse, over and over. Right? The resistance of Aircraft engines does increase over time, They can be out Spec in as short as 3 to 5 years. However people will keep using old plugs as long as "they work". However high plug resistance can damage magnetos, burn points or overheat coil. So just chucking your NGK's every year is cheap and easy.
It is thought that the NGK gives a better spark than a MASSIVE dual electrode Champion. Why. The electrodes block the spark. The electrodes are huge for longevity. You say, "Hey Smarty Pants, there are fine wire Aircraft plugs like EARHM38SE." Yep $120 each. Again it is not performance but similar or same performance for much lower cost. Also with EI putting out a very hot long duration you can open up the NGK gap more and get a bigger spark.
So to answer my own question NGK BR9ES is a good starting point I read. Correct me if wrong. If you want a hotter plug go to an 8. If you want cooler go to a 10. Cost? $3 each.
WARNING** NGK's are favorites to be counterfeit. So make sure you get genuine NGK. If the price is too good to be true it's likely fake. There are ways to tell if you have the real deal (web has some guides for authenticity). Just be aware. The counterfeits work but I read they are not as good as genuine NGK?
Thanks for the replies they are all great. Appreciate the perspective. IF YOU HAVE INSIGHT TO USING NGK'S AND HARNESS KEEP THE COMMENTS COMING.