What does step colders mean for spark plugs? When do I need them I have done most of the bolt-ons(full exhaust, udp, cai), do I need a step colder or to change my gap?

 

step colder doesnt run as hot as the regular ones. I think the NGK is 5g for the hotter and 6g for the step colder. Platinum plugs are already pre gapped so dont worry about that

 

But when do you need to use them?

 

Part of your spark plug’s responsibilities, in addition to firing a spark, is to remove heat from the combustion chamber. This is accomplished by channeling the heat through the insulator material and metal housing. From there, the heat is transferred to the cylinder head where the engine cooling system can go to work. A spark plug’s heat range is its ability to dissipate heat. The “colder” the plug, the more heat it can channel out of the combustion chamber. In a performance application, colder heat ranges may be necessary to handle the extreme temperatures brought on by higher compression ratios, forced induction, and high RPM’s. While “Colder” plugs may seem to be the way to go, please remember that the spark plug must achieve its “self-cleaning” temperature where it can burn off fuel and carbon deposits. Otherwise, the plug could “foul out” where it is prone to misfiring and poor acceleration. A plug that is too “hot” can overheat, also causing power loss, detonation, pre-ignition, and possible engine damage. A good, general rule of thumb is to start with the factory recommended heat range. For every 75 to 100 hp you add to your engine, you may go to the next colder step.

http://www.densoiridium.com/faq.php

 

generally speaking there is no need to go to a colder plug unless you are using forced induction or nitrous. It can actually hinder performance on a n/a car with bolt-ons. (IIRC, that was dyno proven on a max).