What if you only want to go one heat colder? Is the a 11 in the mix? I've heard too many bad things about going 2 steps colder. One works great for me. I've also seen in the Hot rod mags that a platnum plug will give you a bump in HP at the top of the RPM range because the spark stays and doesn't get "blown out" as they put it.
There is no RC11***, so no, a single CHAMPION heat range colder is not possible in the OEM style plug. However, you have to consider this: NO two manufacturers "heat ranges" are exactly same. Your single heat range in whatever plugs you use is not actually 1 heat range colder than stock, since there is no direct comparison between manufacturers. Since these plugs are by the same manufacturer as OEM, you know that these plugs are EXACTLY 140-200 (70-100 C/heat range) degrees C colder than the OEM plugs.
The OEM Projected Tip type plug, available in correct heat ranges ONLY by Champion, does not need to be a very hot plug to keep from fouling. That is, in part, the purpose of the projected tip. When exposed further in the combusion chamber, it reaches self-cleaning temp much faster than a standard plug, and keeps it in that range even at slow speeds. I have PERSONALLY tested this with these plugs, on my own SRT-10. With the RC10ECC, I installed them, and let the car idle for one HOUR, and shut off- no drive time. No fouling. The next test was about a 45 minute highway drive, 5-6 gear, very little accelleration. Again, no fouling. The Viper's have no problems running these plugs. These tests were with Stock settings- modded cars burn even hotter, they should have no problems. (Same tests done on a 6.5 PSI Roe S/C car I now have running these plugs- flawless)
On a side note, I caught your comment about Platinum Tip Plugs. That does not make sense because Platinum plugs actually have the worst burn characteristics of all plug types. Platinum is used because of how long it lasts, not its conductive properties. Iridium is better than Platinum because of its marginally better conductive characteristics, as well as its extreme hardness and breakdown resistance- fine wires help strengthen the spark in comparison with Platinum and Pallidium finewires. In reality, the most power can generally be made with Copper plugs, though they do need to be changed much more often that the other plug types. (Skip White has a lot of insight into this, the Engine Building Shop his family owns always uses Copper plugs in their racing engines if I recall what he said correctly, and they do some of the best work out there) In our types of cars, this makes perfect sense though. For most people, a plug change should occur every 2 years or so. A plug change tells you a lot about how your car is running, and can alert you to impending problems down the road. Anyone with eyes in their head can notice major problems, and a little more skill can go a long way to getting the most out of your car.
