Spark Plug Advice

Yesterday i went out and bought a set of Bosch Platinum +4 spark plugs and new cables. When i took out the plugs that were already in my car i noticed that they are Denso Iridiums and they are in good condition. Now i hear that the Denso Iridiums are the best and that there quite expensive. My question is should i put back in the used Denso’s which i have no idea how old they are or just keep my new platinum +4’s.

I also heard that the platinum +4’s have a spark that burns too hot for a car like an integra, an idiot told me this so i don’t know what to think.

i’m useing the iridiums too but i just recently took them out and put in some bosch something i had before. the iridiums seems to have more power to it so i’m going to change them back cause i thought the iriiums were going bad when i took them out. u can do what u want. just test them out and see. then u’ll have an extra set around in case something happens.

I’d stick with the Denso’s. Next time you go buy spark plugs, just stick with NGK. I haven’t had any problems with those (Plats or Coppers).



I’m using the NGK’s for the RSX-S

if you’re using a high-compression Vtec motor- the one’s for the RSX-S are a heat range colder than the GSR’s


I was using Bosch platinums, but had heard they were more longevity than performance oriented. I switched to NGK iridiums and (after breaking an electrode, buying the wrong part #, and buying the wrong socket to fit the wrong part) I would recommend you go (or stay) iridium. I had a strange condition around 3000 rpm where power would fall off, and then come back at 3500 or so.
I am glad to say the new plugs fixed that, and ther car is noticably smoother throughout the rpm band, with seemingly more low end.
My Bosch plats and my NGK’s were both gapped to exactly .44 too, so my comparison is pretty even. (And no I don’t work for NGK)

And they add 15+ eBay horsepower!!!