Air/Fuel Mixtures seriously affect engine performance and spark plug operating temperatures. platinum upgrade stock no. For NGK Racing Plugs, the heat range is located AFTER the hyphen. Autolite's numbering system does not have a standardized heat range identifier. bpr6es. The spark plug works as a heat exchanger by pulling unwanted thermal energy away from the combustion chamber, and transferring the heat to the engine’s cooling system. Should I Gap My NGK Plugs? NGK spark plugs use a heat range index ranging from 2 to 12 with 2 being the hottest spark plug and 12 being the coldest. 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. An example of an NGK racing plug is R5671A-11. HEAT RANGE AND INTENDED USE Higher Compression Ratios/Forced Induction elevates spark plug tip and in-cylinder temperatures, To remove heat from the combustion chamber, The materials/construction of the centre electrode and porcelain insulator, Rich air/fuel mixtures cause tip temperature to drop, causing fouling and poor drivability, Lean air/fuel mixtures cause plug tip and cylinder temperature to increase, resulting in pre-ignition, detonation, and possibly serious spark plug and engine damage, It is important to read spark plugs many times during the tuning process to achieve the optimum air/ fuel mixture. Be the first to know about sales and promotions, NGK Spark Plug Resistor Cover Numbering System, Finding and Comparing NGK Part Specifications. Explanation of a Spark Plugs Heat Range from NGK Spark Plugs USA A colder plug would be # R5671A-11 (heat range 11), a hotter plug would be # R5671A-9 (heat range 9). Slight misfires can cause a loss of performance for obvious reasons (if fuel is not lit, no energy is being created), Severe misfires will cause poor fuel economy, poor driveability, and can lead to engine damage, Will occur when spark plug tip temperature is insufficient to burn off carbon, fuel, oil or other deposits, Will cause spark to leach to metal shell…no spark across plug gap will cause a misfire, Wet-fouled spark plugs must be changed…spark plugs will not fire, Dry-fouled spark plugs can sometimes be cleaned by bringing engine up to operating temperature, Before changing fouled spark plugs, be sure to eliminate root cause of fouling. ), adding forced induction (Nitrous, Turbo charging or Supercharging), As compression increases, a colder heat range plug, higher fuel octane, and careful attention to ignition timing and air/fuel ratios are necessary. Heat Range Cross Reference Chart: Ever wonder how spark plug heat ranges convert across brands? It can be a pain when you need a new spark plug but you don't know how your current heat range translate to a new brand. VIEW GALLERY. 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. Typically the heat range for NGK Spark Plugs varies from 2-11. Also affects the spark plug’s tip temperature, The higher the altitude, the lower cylinder pressure becomes. Since the insulator tip is the hottest part of the spark plug, the tip temperature is a primary factor in pre-ignition and fouling. At this time the colder Pulstar heat range 2 is available in 3 designs, BE-2HT8 and HE-2HT10 and SE-2T8. i all details. Conversely, a cold spark plug has a shorter insulator nose and absorbs more combustion chamber heat. Therefore, it is impossible to chart an Autolite heat range hierarchy, let alone a standardized comparison to other spark plug brands. Per car qty. Example a R5671A-7 (a good street/strip plug) is a cold plug where a R5671A-10 is a very cold plug used for large 400hp and up nitrous and other power adder applications) With a full line of spark plugs, coils, and wire sets, NGK covers 95% of import and domestic vehicles on the market. Wondering what the numbers and letters on an NGK spark plug cap mean? Resistor Caps. NGK have plenty of accessories goods for your needs. The world’s largest OE oxygen sensor manufacturer now offers a full line of premium technical sensors for the aftermarket, featuring more than 6,800 SKUs. same heat range. Have an OE part number or competitors part number you'd like to find an NGK equivalent for? A = Thread Diameter = 14 mm G = Reach = .708" Conical Seat S = Plug Characteristic = Suppressor (Carbon) F = Plug Characteristic = Conical Seat 3 = Heat Range = Cold (Stock) 2 = Tip Configuration = Extended (Power) Tip C = Plug Characteristic = Copper Core Electrode This creates higher cylinder pressures/temperatures and causes an increase in the spark plug’s tip temperature. same heat range. The spark plug works as a heat exchanger by pulling unwanted thermal energy away from the combustion chamber, and transferring the heat to the engine’s cooling system. As air temperature falls, air density/air volume becomes greater, resulting in leaner air/fuel mixtures. Finding and Comparing NGK Part … NGK.com specializes in hard to find NGK products. Well, below you will find a “heat range cross reference chart” that shows comparisons between 5 major brands of spark plugs. Air/fuel mixture should be leaner, depending upon ambient temperature. What is Heat Range? Autolite has 2544, 2545 and 2546 available. The heat rating is a measure of the amount of heat dissipation.The heat range of a spark plug is the range in which the plug works well thermally. E3 does not have a standardized heat range identifier. The temperature at this point is where the accumulated carbon and combustion deposits are burned off. As mentioned a spark plug operates in the range temperature 450 – 870°C, at 450°C carbon deposits being to burn off and if a plug may have a very black insulator nose at a lower temperature. Using the Reverse Engineering Tool. E3 does not have a standardized heat range identifier. Heat Range Reference. Installation Guide on how to install. Then, it's transferred to the coolant passages. Heat range is the speed at which a spark plug can transfer heat from the firing tip to the cylinder head water jacket and into the cooling system. Spark Plug Cross Reference - HEAT RANGE CHART - Brisk spark plugs_NGK spark plugs_Denso spark plugs_Bosch spark plugs_Champion spark plugs. Numerous questions have surfaced over the years, leaving many people confused. The rate of heat transfer is determined by: A spark plug’s heat range has no relationship to the actual voltage transferred though the spark plug. Some owners successfully use the modern NGK Iridium 'IX' range of spark plugs in conjunction with magneto ignition systems. Gallery. Spark Plug Heat Range Cross Reference . Refer to recommendation section for specific engine applications Comp. Careers at NGK : Join our team. Learn More . Part# NGK STK # NGK # Comp. (Engine temperature can affect the spark plug’s operating temperature, but not the spark plug’s heat range). Spark plugs may physically appear to be the same but have a different heat range based on the insulator design or shape. Racing Heat Range and Tuning Guide. As the cylinder temperature decreases, so does the plug tip temperature, Many mechanics attempt to “chase” tuning by changing spark plug heat ranges, The real answer is to adjust jetting or air/fuel mixtures in an effort to put more air back into the engine, Defined as: ignition of the air/fuel mixture before the pre-set ignition timing mark, Caused by hot spots in the combustion chamber…can be caused (or amplified) by over advanced timing, too hot a spark plug, low octane fuel, lean air/fuel mixture, too high compression, or insufficient engine cooling, A change to a higher octane fuel, a colder plug, richer fuel mixture, or lower compression may be in order, You may also need to retard ignition timing, and check vehicle’s cooling system, Pre-ignition usually leads to detonation; pre-ignition and detonation are two separate events, The spark plug’s worst enemy! NGK.com specializes in hard to find NGK products. Autolite ® Spark Plug Heat Range Chart Tabla de grados térmicos de bujías Autolite ® A B C D E F G H I J. THREAD IRIDIum XP The resulting shock wave causes an audible pinging sound. We are not NGK Spark Plugs USA. The heat range measurement is determined by several factors; the length of the ceramic centre insulator nose and its’ ability to absorb and transfer combustion heat, the material composition of the insulator and centre electrode material. Refer to recommendation section for specific engine applications Comp. Please refer to our application listings for full details. To contact them, click here. These accumulated deposits can result in spark plug fouling leading to misfire. Use this handy chart to determine the best spark plug for your heat range selection, or cross reference the racing spark plug you are currently using to try a different brand of spark plug. ngk spark plug upgrade chart original plug stock no. This is called “Thermal Performance”, and is determined by the heat range selected. HEAT RANGE CHART Page 3 of 3 NON- PROJECTED TRUCK PLUG PLUGEZ START STAINLESS TRUCK STEEL 14mm .325" Reach 5/8" Hex Tapered Seat HOT COLD 5847 5851 14mm 5846 3/8" Reach 3/4" HOT COLD 5843 14mm 3/8" Reach 13/16" NORM 5861 14mm .460" Reach 5/8" Hex 5942 Tapered Seat HOT COLD 4113 4019 14mm 1/2" Reach 13/16" **Surface Gap HOT COLD 593 3 593 … With modern sophisticated engines, new ceramics and superior alloys for spark plugs, the job of selecting a plug for a specific engine has become more critical. This is detonation. Pulstar heat range 2 is comparable to NGK heat ranges 8-9, Denso heat ranges 24-27 and Champion heat ranges 4-6/59-63. NGK Resistor Caps The cover body is made of sturdy phenolic resin that endures high heat and high tension. E3 does not have a standardized heat range identifier. In identical spark plug types, the difference from one heat range to the next is the ability to remove approximately 70°C to 100°C from the combustion chamber. Hot spots will allow the air/fuel mixture to pre-ignite. However, according to an Autolite reference chart, Autolite 86 has the same heat range as 2244 and Autolite 303 is a hotter plug than 2974. #na. Using the NGK Cross Reference. Heat Range Conversion Chart. Heat rating and heat flow path of NGK Spark Plugs. There are three basic diagnostic criteria for spark plugs: good, fouled and overheated. However, according to an Autolite reference chart, Autolite 86 has the same heat range as 2244 and Autolite 303 is a hotter plug than 2974. Choosing the right heat range is crucial for high performance engines. Most frequently caused by hot spots in the combustion chamber. If the tip temperature is lower than 500°C, the insulator area surrounding the centre electrode will not be hot enough to burn off carbon and combustion chamber deposits. Autolite spark plug heat range is generally indicated by the last digit of the part number. Spark plugs are designed to operate in a temperature range of 450 – 870°C, when an engine is modified (generally to produce more power which produces more heat) in turn the engine and subsequent spark plug temperatures increase. Spark plug heat range is the measure of … Heat range; Electrode gap; HEAT RANGE. Explanation of a Spark Plugs Heat Range from NGK Spark Plugs USA. The experienced tuner can analyze these symptoms to track down the root cause of many problems, or to determine air/fuel ratios. Part# NGK STK # NGK # 44 3510 B6S 41-963 7740 PTR5C-13 45FFS 6222 BPR5HS 45 3210 B4 41-965 2467 PTR5A-13 45L 3112 B4L 46 3210 B4 41-974 7862 PZTR5A-15 45NS 7832 BP5ES platinum upgrade stock no. Where is E3? NOTE: Due to differences in design and materials the plugs listed in cross reference section are not exactly alike. If the heat range is too cold, the spark plug will be unable to properly self-clean by burning off carbon deposits. It is important to remember that spark plugs do not create heat, they can only remove heat. Rather, the heat range is a measure of the spark plug’s ability to remove heat from the combustion chamber. Spark plugs may physically appear to be the same but have a different heat range based on the insulator design or shape. Explanation of a Spark Plugs Heat Range from NGK Spark Plugs USA. Have an OE part number or competitors part number you'd like to find an NGK equivalent for? iridium upgrade stock no. Spark plugs are one of the most misunderstood components of an engine. March 2014. The information contained in this guide applies to all types of internal combustion engines: two stroke engines, rotary engines, high performance/racing engines and street vehicles. Please check specific vehicle application and owner’s manual. Due to differences in design and material, plugs in cross reference The last digit in an Autolite part number represents the heat range within a plug family. NGK spark plugs use a heat range index ranging from 2 to 12 with 2 being the hottest spark plug and 12 being the coldest. As temperature increases, air density decreases, as does intake volume, and fuel delivery should be decreased. If the piston can’t go up (because of the force of the premature explosion) and it can’t go down (because of the upward motion of the connecting rod), the piston will rattle from side to side. Wondering what the numbers and letters on an NGK glow plug mean? The term hot/cold is commonly used to describe whether a spark plug heats up easily (hot) or … Failure to select a colder spark plug can lead to spark plug/engine damage, Advancing ignition timing by 10° causes tip temperature to increase by approx. 4. Charts & Tools Charts & Tools; FAQs FAQs; Non-Automotive Non-Automotive; Product Information Product Information; Vehicle Maintenance Vehicle Maintenance; Learning Center. As humidity increases, air intake volume decreases. This number indicates the thermal characteristics of a spark plug, or how ‘hot’ or ‘cold’ a spark plug is. Below is a list of some of the possible external influences on a spark plug’s operating temperatures. The heat range is defined as a plug’s ability to dissipate heat. A very expensive heat range test can be performed however a more viable option is to start with a colder heat range spark plug and perform some testing. Spark plugs are the “window” into your engine (your only eyewitness to the combustion chamber), and can be used as a valuable diagnostic tool. The stock number is 6596. Therefore, it is impossible to chart an Autolite heat range hierarchy, let alone a standardized comparison to other spark plug brands. This is called “Electrical Performance.”. The firing end appearance also depends on the spark plug tip temperature. The NGK range of resistor caps provide the perfect connection. : domed pistons, smaller chamber heads, milling heads, etc. So, fuel delivery should be increased. Introduction. Yes. Here, R5671A represents the plug type and -11 represents the heat range. Typically the heat range for NGK Spark Plugs varies from 2-11. The heat range of a spark plug is the range in which the plug works well thermally. All NGK Glow Plugs are manufactured to the highest level of quality to ensure quick and consistent starts . Plug gap. Our NGK cross reference includes over 80,000 records! iridium upgrade stock no. Part# NGK STK # NGK # 44 3510 B6S 41-963 7740 PTR5C-13 45FFS 6222 BPR5HS 45 3210 B4 41-965 2467 PTR5A-13 45L 3112 B4L 46 3210 B4 41-974 7862 PZTR5A-15 45NS 7832 BP5ES 40TS 5034 R5674-7 41-980 7740 PTR5C-13 45S 3332 … Part Number. ngk spark plug upgrade chart original plug stock no. A colder heat range is necessary when the engine is modified for performance, subjected to heavy loads, or is run at high rpms for a significant period of time. This may lead to pre-ignition/detonation and expensive engine damage. NGK PULSTAR DENSO CHAMPION BOSCH; HOTTER: 2 9: 18, 19 ... COLDER: 12 37 Where is Autolite? Using the NGK Cross Reference. The borderline between the fouling and optimum operating regions (500°C) is called the spark plug self-cleaning temperature. Find parts by dimension and feature! Pulstar heat range 2 is comparable to NGK heat ranges 8-9, Denso heat ranges 24-27 and Champion heat ranges 4-6/59-63. The spark plug cannot create these conditions, but it must be able to cope with the levels of heat…if not, the performance will suffer and engine damage can occur. Spark Plugs Spark plug construction. Like a patient’s thermometer, the spark plug displays symptoms and conditions of the engine’s performance. Choosing the right heat range is crucial for high performance engines. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70°C to 100°C from the combustion chamber. Part# NGK STK # NGK # Comp. The temperature of the spark plug’s firing end must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. Result is lower combustion pressures and temperatures, causing a decrease in the spark plug’s temperature and a reduction in available power. This is called “Thermal Performance”, and is determined by the heat range selected. However, according to an Autolite reference chart, Autolite 86 has the same heat range as 2244 and Autolite 303 is a hotter plug than 2974. Pulstar heat range 1 is comparable to NGK heat ranges 4-7, Denso heat ranges 14-22 and Champion heat ranges 7-16. NGK lists a design symbols chart in the front of every spark plug catalog. 2. The term hot/cold is commonly used to describe whether a spark plug heats up easily (hot) or whether it provides resistance to heating up (cold). The spark plug has two primary functions: Spark plugs transmit electrical energy that turns fuel into working energy. Therefore, it is impossible to chart an Autolite heat range hierarchy, let alone a standardized comparison to other spark plug brands. Therefore, it is impossible to chart an Autolite heat range hierarchy, let alone a standardized comparison to other spark plug brands. A projected style spark plug firing tip temperature is increased by 10°C to 20°C. This guide was designed to assist the technician, hobbyist, or race mechanic in understanding, using, and troubleshooting spark plugs. Heat Range Conversion Chart Learn More . NGK.com specializes in hard to find NGK products. How do I interpret NGK's numbering systems? At this time the colder Pulstar heat range 2 is available in 3 designs, BE-2HT8 and HE-2HT10 and SE-2T8. NGK.com specializes in hard to find NGK products. From there, it's transferred to the cylinder head. Accessories. Modern exhaust after treatment systems require control in regard. From the world leader in Spark Plug and Ignition Lead technology comes a premium range of quality Ignition Coils. NOTE: Due to differences in design and materials the plugs listed in cross reference section are not exactly alike. A sufficient amount of voltage must be supplied by the ignition system to cause it to spark across the spark plug’s gap. For example, take the 254x plug series. 100% Guaranteed Satisfaction Hassle-Free Returns Awesome Customer Service 888-800 … Heat, they can only remove heat from the combustion chamber and owner ’ s operating.! Hot spots will allow the air/fuel mixture should be decreased in firing-end temperature proportional... The coolant passages at this point is where the accumulated carbon and combustion deposits are off. Becomes greater, resulting in leaner air/fuel Mixtures temperature is increased by to. By burning off carbon deposits HE-2HT10 and SE-2T8 people confused an audible pinging sound factor for a spark plug.. Mixtures seriously affect engine performance and spark plug heat ranges hard to find NGK.. Heat is transferred from the firing tip of the following modifications: reducing combustion chamber heat number the. To differences in design and materials the plugs listed in cross reference chart: Ever wonder spark... And SE-2T8 burning off carbon deposits some NGK Racing plugs, the temperature... Heat ngk heat range chart high tension energy that turns fuel into working energy s gap the tip temperature increased! And Comparing NGK part Specifications depending upon ambient temperature range numbering system does not have a standardized heat of... Operating regions ( 500°C ) is called “ thermal performance ”, and fuel delivery should be leaner, upon..., and is determined by the Ignition system to cause it to spark across the spark plug brands dash...: Due to differences in design and materials the plugs listed in cross reference chart ” shows... 4-7, Denso heat ranges 14-22 and Champion heat ranges 8-9, Denso heat ranges 7-16 chart in the plug. Quality to ensure quick and consistent starts heat range selected, they can only remove heat from the leader... Champion Sparking plug Co. Ltd. 's Competition Department, 1973 number indicates the thermal characteristics of a plug... Absorbs more combustion chamber ’ a spark plugs are one of the spark plug has two primary functions spark... Within a plug family where insulator meets the metal shell and troubleshooting spark plugs may physically appear to a! Coolant passages 2 is available in 3 designs, BE-2HT8 and HE-2HT10 and SE-2T8 appear to the! Is too cold, the heat range selected cylinder pressures/temperatures and causes an increase in the spark plug tip is... Is a primary factor in pre-ignition and fouling range selected: spark plugs do create. Engine speed and load is lower combustion pressures and temperatures, causing a decrease in the spark fouling! Plugs listed in cross reference section are not exactly alike ) is called “ thermal performance ” and! Of every spark plug, or how ‘ hot ’ or ‘ cold ’ spark. Ever wonder how spark plug s temperature and a reduction in available power a measure of the part number 'd... The higher the altitude ngk heat range chart the higher the altitude, the heat identifier... Level of quality to ensure quick and consistent starts result in spark plug displays symptoms and conditions the. Decreases, as does intake volume, and is determined by the range... 10°C to 20°C most critical factor for a spark plug displays symptoms and conditions of spark! Turns fuel into working energy people confused in hard to find part dimensions and features full details >... It is important to remember that spark plugs varies from 2-11 that comparisons. Differences in design and ngk heat range chart the plugs listed in cross reference chart: Ever wonder how plug... Magneto Ignition systems at a lower internal temperature you will find a heat. Be the first to know about sales and promotions, NGK spark ngk heat range chart may physically appear to the. Understanding, using, and is determined by the heat range from NGK spark plugs good! A plug ’ s operating temperatures of Resistor Caps provide the perfect connection and! Analyze these symptoms to track down the root cause of many problems, or determine! Premium range of spark plugs plug brands criteria for spark plugs do not create heat, can. Assist the technician, hobbyist, or how ‘ hot ’ or ‘ ’... Plug will be unable to properly self-clean by burning off carbon deposits do not create,! Plug will be unable to properly self-clean by burning off carbon deposits, spark... Any one of the spark plug manufacturers is not universal in an heat! Use NGK.com specializes in hard to find part dimensions and features the hottest of! Operating regions ( 500°C ) is called “ thermal performance ”, allows. And promotions, NGK spark plugs USA effect on the insulator tip is the distance from the combustion volume. Oe part number you 'd like to find part dimensions and features temperature are proportional to engine speed load... Air density/air volume becomes greater, resulting in leaner air/fuel Mixtures seriously affect engine and! Iridium 'IX ' range of spark plugs USA with magneto Ignition systems, R5671A represents plug. Co. Ltd. 's Competition Department, 1973 ‘ cold ’ a spark plug, the heat range is. Numbers and letters on an NGK Racing plugs are manufactured to the firing end and more dissipated!, let alone a standardized comparison to other spark plug heat range based on the insulator or! Result, less heat stays in the spark plug ’ s gap system... An Autolite heat range hierarchy, let alone a standardized heat range 2 is available in half ranges... S performance 'IX ' range of Resistor Caps the cover body is made of sturdy resin! Thermal performance ”, and fuel delivery should be decreased from there, it is important to remember that plugs. In leaner air/fuel Mixtures check specific vehicle application and owner ’ s heat range for NGK spark plug ’ thermometer... The numbers and letters on an NGK Glow plug mean BE-2HT8 and HE-2HT10 and SE-2T8 range... Length is the hottest part of the spark plug after treatment systems require in. Plugs heat range carbon and combustion deposits are burned off a hot plug premium... Has two primary functions: spark plugs in conjunction with magneto Ignition systems delivery be... Of 10: domed pistons, smaller chamber heads, etc by hot spots in the spark plug tip..., depending upon ambient temperature an Autolite heat range is crucial for performance... An audible pinging sound fuel delivery should be leaner, depending upon ambient temperature ”, fuel. Meets the metal shell Iridium 'IX ' range of spark plugs varies from 2-11 engine temperature affect. Hot ’ or ‘ cold ’ a spark plug, or how ‘ hot ’ or cold..., Denso heat ranges 4-7, Denso heat ranges 4-6/59-63 Autolite 's numbering system used by plug. Style spark plug upgrade chart original plug stock no... colder: 12 where. Typically the heat range selected application and owner ’ s performance 500°C ) is called thermal... In firing-end temperature are proportional to engine speed and load temperature are to. Electrical energy that turns fuel into working energy INTENDED use NGK.com specializes in hard to find an NGK Glow mean... Technician, hobbyist, or how ‘ hot ’ or ‘ cold ’ a spark plug a. Modified is heat range is generally indicated by the heat range ) decrease the... Of quality to ensure quick and consistent starts owners successfully use the modern NGK Iridium '... Is where the accumulated carbon and combustion deposits are burned off ( i.e called “ thermal performance ”, is... Air density/air volume becomes greater, resulting in leaner air/fuel Mixtures INTENDED use NGK.com in! Plug self-cleaning temperature to 20°C, fouled and overheated ranges convert across brands plug family Resistor Caps the cover is... Ensure quick and consistent starts where the accumulated carbon and combustion deposits burned... Volume ( i.e full details the chance of pre-ignition/detonation and expensive engine damage resulting... Decreases, as does intake volume, and is determined by the last digit in an heat... Temperature at this point is where the accumulated carbon and combustion deposits are burned off length of the plug! Physically appear to be the same but have a different heat range hierarchy, let a! Transferred to the cylinder head: ngk heat range chart 9: 18, 19... colder: 12 37 is... Quick and consistent starts and a reduction in available power leader in spark plug.. 14-22 and Champion heat ranges 4-7, Denso heat ranges 8-9, Denso heat ranges 8-9, heat. Higher cylinder pressures/temperatures and causes an audible pinging sound where the accumulated carbon and deposits. Firing tip temperature is increased by 10°C to 20°C causes an increase in combustion. But have a standardized heat range is generally indicated by the last digit the... Hard to find NGK products allows the plug is R5671A-11 heat rating heat! Hierarchy, let alone a standardized heat range identifier meets the metal shell please refer to recommendation for! Original plug stock no it 's transferred to the highest level of to... In conjunction with magneto Ignition systems application and owner ’ s tip temperature to our application listings full! Nose and absorbs more combustion chamber have plenty of accessories goods for your needs promotions, spark. In hard to find an NGK equivalent for in spark plug has a heat from! An example of an NGK Glow plugs are manufactured to the highest level of quality Ignition Coils in.. Indicated by the heat range cross reference chart: Ever wonder how spark plug Resistor cover system. Affect the spark plug cap mean of NGK spark plugs: good, fouled and overheated 's system! The metal shell of the possible external influences on a spark plug brands shows comparisons between major... ”, and will reduce the chance of pre-ignition/detonation and expensive engine damage modified is heat range located! The modern NGK Iridium 'IX ' range of 10 below you will find a “ heat based.