I had a 72 Dodge Dart Demon. 340ci V-8 that was tuned up pretty well and had the kind of strong engine that pulled 0-60 in about 6.7sec and regularly pulled mid 15's on the 1/4 mile drag strip.
I used to run some slightly "hotter" plugs in it trying for more "juice" and about the only thing it seemed to do was make the car start a little easier. I tracked absolutely NO difference in horsepower (had access to a dyno) or MPG or 1/4 mile speed or anything.
1997 Jeep Cherokee, decided to try some "fancy" NGK plugs one time and it was astoundingly awful. Lowered MPG, one cylinder fouled (which had NEVER happened before). Truly a disaster. I went back to the stock Champion plugs and have been happy for the last 160+k miles.
My own personal experience has been that the factory recommended plugs are generally about the best thing you can put in a regular commuter car.
I used to run some slightly "hotter" plugs in it trying for more "juice" and about the only thing it seemed to do was make the car start a little easier. I tracked absolutely NO difference in horsepower (had access to a dyno) or MPG or 1/4 mile speed or anything.
1997 Jeep Cherokee, decided to try some "fancy" NGK plugs one time and it was astoundingly awful. Lowered MPG, one cylinder fouled (which had NEVER happened before). Truly a disaster. I went back to the stock Champion plugs and have been happy for the last 160+k miles.
My own personal experience has been that the factory recommended plugs are generally about the best thing you can put in a regular commuter car.
