Ive used them in a couple of vehicles when I was a teen. They were both 4 cylinders that were well past thier lifespan and oil was fouling the plugs from the bottom up. They kept the plugs nice and clean, but they move the spark plugs further out of the combustion chamber which isnt optimum for promoting good flame travel. In both my experiences with them, they seriously reduced spark plug lifespan to about 10k miles before I would start developing a miss, even on unfouled plugs, but that beat oil fouled plugs constantly. In my opinion, I would stay away from them unless you are trying to milk every last mile out of a worn out engine. Sorry I couldnt specifically answer your question though.