If you've been around the SRT-4 community you may have heard of these. The spark plugs I'm talking about are stock 5.7L Hemi V8 plugs (Champion 570 / RE14MCC4). This is one of those things that it will work with your car or not. Just like any other spark plugs. Some prefer the OEM Champions and some prefer NGK 4306 and then there's the others. Some take liking to one SRT-4 but don't to others. This holds true that every SRT-4 is different in one way or another. Now to the rumors. Some have said these run 1 step colder and some say 2 step colder then the stock Champions (470). This is not true. They are both the same heat range and the only difference is they are designed to be gapped closer. Interested in giving them a "GO"... If you go to the dealership the part # is SPRE14MCC4. Let them know you only need 4 because they will try to sell you all 16.
Nope no risks (haven't found any at all). Like I stated some SRT-4's like them some don't. Some have had great experience with them. There's a few locals running these as well as other people in different states. This info is nothing new, its been within the SRT-4 community for a few years now. These are great plugs in which some will benefit more then others using them. For a set of (4) it cost me $14.77 with tax at the dealership. I've tried many different spark plugs with my car and out of all... mine likes the NGK 4306. You'll notice the difference in performance between the plugs you had to these. It will either be better or not.
If the stock 5.7 plugs are the same heat range as the stock SRT4 plug, then you could also go to the 6.1 plug which is 1 step colder than the 5.7 plug or to NGK 2315's which are 2 steps colder than the stock 5.7 plug.
It depends on your motor and mods. The general rule of thumb is to go one step colder for every 75-100 HP over stock. If you go too cold, your plugs will foul.
Well I don't have 75-100hp over stock to go one step colder. I have tried the Hemi style plugs, I liked them a lot. I honestly never had any trouble with plugs or I didn't know the difference in my cars performance. I am currently running the V-Power 4306 coppers.
Anyone ever try these? http://www.pulstarplug.com/index.html They have them for the 5.7L, but no SRT other than the 10.
You should swap to a colder plug if your encountering spark blowout and you have the NGK 4306's(or Champions) gapped tight to begin with(ie. .030 or lower). A colder plug running wider gap will give a stronger spark and better drivibility. A colder plug is less prone to pre-detonation(knock) due to heat at higher HP levels...more HP equals more heat in the combustion chamber. The NGK 4306's or Champion 570's are more than enough plug for a full bolt-on stock turbo.
Smoke and mirrors....think along the lines of Splitfire plugs. Also you should NEVER run these on a forced inducted engine, a platnium electrode retains heat. This can/will cause pre-detonation in a turbo/super application.
