try closing your spark plug gap. I always ran .020 in my turbo street/drag bike with ngk cr9e's. I ran up to 19lbs of boost with this. They are cheap and I just changed them often running strait c16 gas. I left them in for a month in a half once. I was in sacramento and it was kind of cutting out on the top end and not running good. Put in new plugs and picked up 4mph to 176mph in the 1/4 on the next run. Changed them every other weekend after that. If you are running under 10lbs of boost try around .025 If that does not work try .020 and see how it works.
** try this with br9e's, cr9e's are the same plug, just different threads **