You "should" be but make sure they are gapped narrower for FI and it's good practice to pull them every few months and "read" them to see how your engine is doing. You don't want to find out that you're running too lean.

Nothing wrong with the stock platinum plugs for this application although some have reported slightly better performance from the Iridium plugs.

 

i just e-mailed comptech and they said the spark plugs come pregapped. and not to mess with it anymore or else you can mess up the electrode.

 

Just check the gap to be sure it wasn't dropped.

I'm a firm believer of OEM plugs for NA.

 

"dropped" meaning literally? also, does this apply if you are FI?

i don't know if i have failed spark plugs or could be something else but i started noticing 2 days ago, between 4-8k rpm range (ap2) that when i let off the throttle i hear something that goes something like "vvvvrrrrmmmmmvvvvrrmmmm" when i think the engine should be winding down smoothly like "vrrrrrrrrrrmmmm" to quiet. if that makes anything sense at all.

 

They all come "pre-gapped". That doesn't mean they will be the correct gap when you get them for your particular application. You don't actually think that the spark plugs you get were ONLY meant for your car, for your application, do you?

"Mess up the electrode". They have to target this to the lowest common denominator - the biggest cluts there are in the world, the ones who will, without a doubt, mess up the electrode. Thus, they tell you don't do anything to it. It's better sometimes to run the wrong gap than to run a plug that doesn't work at all.
ALWAYS check the gap. If they're correct, then fine. However, if one is wrong, then what are you going to do? Leave it alone and put it in anyway?

 

Bad spark plugs will show themselves on acceleration and coasting, not decelerating between a set rpm range. Since your injectors shut off on deceleration, your plugs aren't doing anything anyway. You're most like changing spark plugs for nothing.

 

You said that iridium sparks might be okay for an NA application... Would these iridium sparks be IK22 still or IK24 as well? If one was putting down 235+ whp NA (raised compression, ported/polished head, EMS, etc.), what plugs would you recommend? And what gap?
Xviper - you da man!!!!!

 

You should attempt to use the coldest heat range of plugs that the engine will handle without fouling. In the case of an NA S2000 engine, many people have been using IK-24 (one heat range colder) in completely stock configurations without incident.
Insofar as "raised compression", I don't believe this alone on a NA engine would have the same problems as a F.I. engine in terms of blowing out the spark. I would go with IK-24 and a 0.040" gap to start with. After a couple thousand miles, take them out and see what they look like. This, more than anything, will tell you far more than to try and guess what might be best to begin with. From the condition of the plugs at that time, you can decide to go another step colder. A high rpm miss might be an indicator that you need to close the gap a bit more.

 

Thanks a lot. Looks like I wont be selling my IK24s that were bought for my SC plan!

 

If you go S/C, you might not want to use them: