Colder plugs on stock SS/SC?
Is it possible to run colder plugs on a stock S/C SS? If so, what are the benefits of this? 
12-20-2007, 09:21 PM
#4
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Spark Plug Heat Range:
A spark plug's heat range has no relationship on the actual voltage transferred through the spark plug. Rather, the heat range is a measure of the spark plug's ability to remove heat from the combustion chamber. The heat range measurement is determined by several factors:
The length of the ceramic center insulator nose
The insulator nose's ability to absorb and transfer combustion heat
The material composition of the insulator
The material composition of the center electrode
The longer the insulator nose gives you a larger surface area exposed to combustion gasses and heat is dissipated slowly. This also means the firing end heats up more quickly. We are talking about exposed ceramic length, not extended tip length.
The insulator nose length is the distance from the firing tip of the insulator to the point where the insulator meets the metal shell. Since the insulator tip is the hottest part of the spark plug, the tip temperature is a primary factor in pre-ignition and fouling. No matter what the plugs are installed in, be it a lawnmower, a boat, your daily driver or your race car, the spark plug tip temperature must remain between 450°C to 850°C. If the tip temperature is lower than 450°C, the insulator area surrounding the center electrode will not be hot enough to deter fouling and carbon deposit build-ups, thus causing misfires. If the tip temperature exceeds 850°C, the spark plug will overheat which can cause the ceramic around the the center electrode to blister as well as the electrodes will begin to melt. This may lead to pre-ignition/detonation and expensive engine damage. (see the plug pictures that are part of this article)
In identical spark plugs, the differences from one heat range to the next is the ability to remove approximately 70°C to 100°C from the combustion chamber. A projected style spark plug firing temperature is increased by 10°C to 20°C.
The firing end appearance also depends on the spark plug tip temperature. There are three basic diagnostic criteria for spark plugs: good, fouled, and overheated. The borderline between the fouling and optimum operating regions (450°C) is called the spark plug self-cleaning temperature. This is the temperature point where the accumulated carbon and combustion deposits are burned off automatically.
Bearing in mind that the insulator nose length is a determining factor in the heat range of a spark plug, the longer the insulator nose, the less heat is absorbed, and the further the heat must travel into the cylinder head water journals. This means that the plug has a higher internal temperature, and is said to be a "Hot" plug. A hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity.
Conversely, a "Cold" spark plug has a shorter insulator nose and absorbs more combustion chamber heat. This heat travels a shorter distance, and allows the plug to operate at a lower internal temperature. A colder heat range can be necessary when an engine is modified for performance, subjected to heavy loads, or it is run at high RPMs for significant periods of time. The higher cylinder pressures developed by high compression, large camshafts, blowers and nitrous oxide, not to mention the RPM ranges we run our engines at while racing, make colder plugs mandatory to eliminate plug overheating and engine damage. The colder type plug removes heat more quickly, and will reduce the chance of pre-ignition/detonation and burn-out of the firing end. (Engine temperatures can affect the spark plug's operating temperature, but not the spark plug's heat range).
A spark plug's heat range has no relationship on the actual voltage transferred through the spark plug. Rather, the heat range is a measure of the spark plug's ability to remove heat from the combustion chamber. The heat range measurement is determined by several factors:
The length of the ceramic center insulator nose
The insulator nose's ability to absorb and transfer combustion heat
The material composition of the insulator
The material composition of the center electrode
The longer the insulator nose gives you a larger surface area exposed to combustion gasses and heat is dissipated slowly. This also means the firing end heats up more quickly. We are talking about exposed ceramic length, not extended tip length.
The insulator nose length is the distance from the firing tip of the insulator to the point where the insulator meets the metal shell. Since the insulator tip is the hottest part of the spark plug, the tip temperature is a primary factor in pre-ignition and fouling. No matter what the plugs are installed in, be it a lawnmower, a boat, your daily driver or your race car, the spark plug tip temperature must remain between 450°C to 850°C. If the tip temperature is lower than 450°C, the insulator area surrounding the center electrode will not be hot enough to deter fouling and carbon deposit build-ups, thus causing misfires. If the tip temperature exceeds 850°C, the spark plug will overheat which can cause the ceramic around the the center electrode to blister as well as the electrodes will begin to melt. This may lead to pre-ignition/detonation and expensive engine damage. (see the plug pictures that are part of this article)
In identical spark plugs, the differences from one heat range to the next is the ability to remove approximately 70°C to 100°C from the combustion chamber. A projected style spark plug firing temperature is increased by 10°C to 20°C.
The firing end appearance also depends on the spark plug tip temperature. There are three basic diagnostic criteria for spark plugs: good, fouled, and overheated. The borderline between the fouling and optimum operating regions (450°C) is called the spark plug self-cleaning temperature. This is the temperature point where the accumulated carbon and combustion deposits are burned off automatically.
Bearing in mind that the insulator nose length is a determining factor in the heat range of a spark plug, the longer the insulator nose, the less heat is absorbed, and the further the heat must travel into the cylinder head water journals. This means that the plug has a higher internal temperature, and is said to be a "Hot" plug. A hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity.
Conversely, a "Cold" spark plug has a shorter insulator nose and absorbs more combustion chamber heat. This heat travels a shorter distance, and allows the plug to operate at a lower internal temperature. A colder heat range can be necessary when an engine is modified for performance, subjected to heavy loads, or it is run at high RPMs for significant periods of time. The higher cylinder pressures developed by high compression, large camshafts, blowers and nitrous oxide, not to mention the RPM ranges we run our engines at while racing, make colder plugs mandatory to eliminate plug overheating and engine damage. The colder type plug removes heat more quickly, and will reduce the chance of pre-ignition/detonation and burn-out of the firing end. (Engine temperatures can affect the spark plug's operating temperature, but not the spark plug's heat range).
12-20-2007, 09:22 PM
#5
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Another question... Do I need any cooling moddifications to run the 2.7pulley?
12-20-2007, 09:26 PM
#7
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but it is safe to run them in my car... i plan on running a 2.7 pulley and having more boost, but im just planning ahead of time. If i can run the plugs and put them in earlier it will save some time when i get the pulleys.
Another question... Do I need any cooling moddifications to run the 2.7pulley?
Another question... Do I need any cooling moddifications to run the 2.7pulley?
but just wait and install them when you need them.
changing plugs takes 10 minutes tops.
too cold can cause deposits to form, and the plug can start shorting out
12-20-2007, 10:21 PM
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12-20-2007, 10:28 PM
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12-20-2007, 10:31 PM
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Brk7e are one step colder ngk
your plusgs are right on top under a cover you have to take off
your plusgs are right on top under a cover you have to take off
Last edited by poppagun; 12-20-2007 at 10:31 PM. Reason: Automerged Doublepost
12-20-2007, 10:32 PM
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12-20-2007, 10:34 PM
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an0malous coming thru with education FACTS...please people be like this...only stat FACTS not "IMO" unless u are saying its in ur opinion..some people take it to heart
12-20-2007, 10:36 PM
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Colder plugs are a waste of money for a stock SS/SC. Even for a stage II cobalt it won't be a benefit. Anything smaller then a 2.99 pulley should go with one step colder. Or if you have stage II and alot of other mods giving you around 260+hp. Also depends alot on your tune.
12-21-2007, 06:59 AM
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1 Step colder plugs on a stock SS/SC will most likely cause hesitation when the car is cold . If you don't let your car warm up to operating temp you will notice this , especially in winter . I run bkr7e's with a stage 3 pulley on a stage 2 tune , but in all honesty i could have gone without them until summer .
12-21-2007, 07:08 AM
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I will agree with the masses here, it is unecessary in a stock SS/SC.
Stage 2 Cars it's getting to the point where it is a good idea! I went to the Bkr7e's when I dropped to the 2.85" pulley.
***Note to self.... I should prolly change them again here shortly***
Stage 2 Cars it's getting to the point where it is a good idea! I went to the Bkr7e's when I dropped to the 2.85" pulley.
***Note to self.... I should prolly change them again here shortly***
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