What would be the result of using a plug one step colder than OEM in a N/A engine?

Would it result in excessive fouling of the plug?

Would there be any benefit?

 

No benefits whatsoever on an NA engine, and more than likely you'll foul the plugs faster.

Only use colder plugs if the combustion environment will be "hotter" as in under boost or extremely high compression. So the only time you really want to go colder on NA is if you increased the compression ratio of the engine.

 

what about if you have engine pinging... will the colder plugs help then?

 

i believe that's what the service manual calls for if there is pinging...