when is a good time or a good reason to change from the stock platinum plugs to the NGK or denso. I can understand running a colder range plug during the use of nitrous or other forced induction, but what about the N/A. Will i see a noticealble gain in at least fuel economy by switching to another plug with the mods in my signature?

 

Until you spray or FI, I can't imagine plugs making a difference until the factory ones had extremely high mileage or some failure related to a poor tune(fouling, detonation damage, etc.).

 

I agree. It's something cheap and easy to do but not necessary to do often to a stock,or near stock,engine. In the old days of weak ignition systems (points,etc.) you'd get misfiring pretty quick at higher rpms. I had a 340 that needed them monthly to get 5,500 rpm out of it.
I changed plugs in my old econobox Civic...Bosch P+4s with 60k+...and noticed very little difference with the new (same type) ones.
If you have an engine that can really punish a stock (or other) ign. sys than it's a different story.

 

I didn't see anything from swapping my plugs...

 

i spray, so i usually change them every time i change my oil.

TR6's are like $13 bucks over here.

 

If I have always had pretty bad detonation, would it be a good idea to change them out now (50K miles)? It doesnt idle as well as is used to... not terrible, but has vibrations and isnt as smooth as it used to be. What would be a good plug to swith to for an NA motor?

 

ttt for my question (above)!
thanks guys!