Sorry fellas, I know this has been drilled before, but the search engine did not produce any solid results. I am getting headers put on next week and want to change the plugs. I remember that everyone likes the NGK TR55, but is it the Iridium or Platinum that is best to go with? Also, is there any advantage to putting on new plug wires as well? The car only has 14k miles on it. Let me know. Thanks. :cheers:

 

You are going to get different opinions on this but I feel the the new ignitons throw such a spark that the advantages of copper plugs are no longer there or are so small that they aren't worth the hassle of frequent changes.

Also he folks at NGK E_Mailed me and said the Iridium was their highest performing plug. I dynoed my car and it showed 316 (SAE corrected) with just a Z06 air box) with the NGK TR55IX iridium plug. Corvette is now using their version of this plug GM# 12571164 Delco #41-985) as the OEM plug and are claiming 100K so it's one of those things that you should be able to install once and not do again for a long time.

Take a look at http://www.rockauto.com/ if you want to buy the new GM iridium plugs and http://www.sparkplugs.com for other brands including NGK.

Unless you need mechanical heat protection I would guess your spark plug wires are fine. GM says you don't need to change the plug wires unless the wires measure over 700 ohms. The ones I have measured have been in the 300 to 400 ohm area. There seems to be some companies that pitch low resistance plug wires as a signifigant selling feature. This always surprises me as the plug already has a 5000 ohm resistor built in which means a couple of hundred ohms on the plug wires is going to make no difference on a modern car with electronic ignition. Plug wires really do need some resistance to supress electrical impulse noise.

That's what I have found. I'm sure you will get other opinions.



[Modified by Richin Chicago, 12:28 PM 5/28/2004]

 

I bought the iridiums because they were out of TR55's. They work great. No issues...


[Modified by blackjack, 7:04 PM 5/29/2004]