Why do people run a step colder?
10-15-2014, 07:12 PM
#4
Senior Member
Since spark plugs must remove heat and a modified engine makes more heat, the spark plug must remove more heat. A colder heat range spark plug must be selected and plug gaps should be adjusted smaller to ensure proper ignitability in this denser air/fuel mixture.
Typically, for every 75-100 hp you add, you should go one step colder on the spark plug's heat range. A hotter heat range is not usually recommended except when severe oil or fuel fouling is occurring.
hope that helps OP.
Typically, for every 75-100 hp you add, you should go one step colder on the spark plug's heat range. A hotter heat range is not usually recommended except when severe oil or fuel fouling is occurring.
hope that helps OP.
10-15-2014, 07:13 PM
#5
Since spark plugs must remove heat and a modified engine makes more heat, the spark plug must remove more heat. A colder heat range spark plug must be selected and plug gaps should be adjusted smaller to ensure proper ignitability in this denser air/fuel mixture. Typically, for every 75-100 hp you add, you should go one step colder on the spark plug's heat range. A hotter heat range is not usually recommended except when severe oil or fuel fouling is occurring. hope that helps OP.
10-15-2014, 07:42 PM
#7
Senior Member
I didn't know the technical answer and have been curious myself, so i looked it up and was helpful rather than giving a useless response. Not really showing off, NGK gave me the answer.
10-16-2014, 10:21 PM
#13
Increased combustion pressure from increasing horsepower in turn increases cylinder temperatures. Plug's are designed to dissipate their captured heat into the surrounding material of the cylinder head. The heat range is determined by the amount of insulation of the ceramic surrounding the electrode. For a colder burning cylinder/low horsepower motor, the plug is insulated further towards the tip so that the plug reaches its operating temperature. If you increase the temperature inside the cylinder and the plug is no longer able to maintain its operating temperature, the plug can melt. Typically you can determine if your plug is cold or hot by looking at the discoloration on the threads on a new recently ran plug with some miles on it. Ideally you want the first 3 threads to be slightly discolored. If no threads are discoloring then typically the plug is cold, if the discoloration is further up the plug typically its running hot. There are other things you can also look at on a plug to determine this as well.
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