Spark Plug Information
Here is some good information compiled by myself and Brandon from NGK. Now these are all NGK plugs. I use NGK for two reasons:
1) They make exceptional product and are OEM manufacturers on many platforms.
2) Their tech support ( I always deal with Brandon.) is simply amazing. They are fairly fast for a company of their size and are very knowledgeable. Polite as well.
Stock or near stock:
This is a projected tip #5 heat range plug. This is the plug I would recommend for stock replacement as well as cars with minor mods such as intake/exhaust. If you have increased boost or are ready for nitrous see below.
Higher than stock boost OR nitrous:
This is the same projected tip plug as above, but in a #6 heat range. If you are going to hit the car with nitrous less than a 75 shot OR increase boost, then you need to go to this heat range plug.
Higher than stock boost AND nitrous:
Again same plug, two heat ranges colder than stock, resulting in a #7 heat range. This is plug I recommend for cars with high psi and nitrous. Now if you have stock psi but a fairly large nitrous shot, I would also recommend going to this plug. I think at 75 shot its optional but recommend, after that I would call it mandatory.
Little general plug tech
There are projected and non-projected type plugs. It means just what it says, the electrode of the plug either protrudes from the end of the threads, or it does not. Generally, non-projected tip are preferred in nitrous applications. However, These are not available for the srt-4. While I would prefer them, its fine to run on the plugs at hand as long as the tune is safe.
In performance applications it is at times needed to go to a "colder" spark plug. This is in reference to the amount of heat a spark plug will release into the cylinder head. It is in no way a reference to the amount of spark or the temperature of the spark. This is a common misconception tho.
I know some read a previous post I made on spark plug and choosing them for you vehicle. This is simply a cleaner more organized format. The information is the same.
Last edited by NitrousExpress; 09-21-2010 at 03:23 PM.