how necessary is it to change your ngk bpr7es spark plugs, they say every 3000 miles, but is that seriously necessary? its been 5000 so far on mine, i will change next oil change if i must. thanks in advdance

 

No it's not,as long as the car runs fine don't change the plugs.Why spend money for no good reason.

#5

 

I have the BPR7es. Will I have a problem switching back to the iridium plug?

Thanks,

 

^ I switched to iridium.. No problems after, imo it runs cherry!

 

dont worry about changing plugs unless u hav running problems

 

general rule of thumb for those running copper plugs is every other oil change should be fine unless you begin misfiring or breaking up under boost.

 

although, i would check the gapping on your plugs every oil change. Just to make sure they havent spread or closed any.

 

does plugs gap changes over time?

 

yes they do widen. copper widens sooner than platinum or iridium. that is why they need to be replaced more often. also, the smaller the gap, the longer they last, but it also means the spark will be smaller and may not fully combust. when u gap them wider, you will get a bigger spark allowing for a complete combustion, but you will risk blowout and the bigger spark puts more wear on the metal (bigger gap= replace often, smaller gap= not so often) which is y you should be in somewhere in the middle.
here is a nifty little website I found:
All About Spark Plugs

hope this helps.... and if you're running high boost, I recommend using copper.

 

I ALWAYS ALWAYS change mine every oil change. They are cheap. Seriously, if you have an evo and its an VIII, just change them every oil change, you will get better gas mileage and the car will just plain run better. Not worth it IMHO to not do them, especially if you romp on your car alot. If its just an occasional driver, then every other should be fine.

 

on a turbo vehicle id say its very important to change them often at least by the service manual change recommendations