vizmark Posted March 31, 2011 Report Share Posted March 31, 2011 There are three different spark plug choices listed in the manual-the hotter B7es, the standard B8es, or the colder B9es. What is the difference between them and how do you choose which one is best for your application. Thanks. Quote Link to comment Share on other sites More sharing options...
Phelps Posted March 31, 2011 Report Share Posted March 31, 2011 no need in ever running 7's, 8's cover almost anything and 9's for alky and nitrous aps. Quote Link to comment Share on other sites More sharing options...
bansheesandrider Posted April 1, 2011 Report Share Posted April 1, 2011 I don't know what manual recomends a 7, the factory manuals I have ALL say to use an 8. All Banshees running on gasoline should use an 8, if you are running alky or nitrous will probably use a 9 as Phelps said. Quote Link to comment Share on other sites More sharing options...
vizmark Posted April 2, 2011 Author Report Share Posted April 2, 2011 hotter B7es, the standard B8es, or the colder B9es. I was wondering if your jetting was just a little rich and you used a #7 plug if it would help balance things out. Quote Link to comment Share on other sites More sharing options...
bansheesandrider Posted April 2, 2011 Report Share Posted April 2, 2011 hotter B7es, the standard B8es, or the colder B9es. I was wondering if your jetting was just a little rich and you used a #7 plug if it would help balance things out. No, you need to jet it properly. If it is too rich then you are wasting fuel, the hotter plug MIGHT keep it from fouling as fast but it is still not going to run as hard as it should because it is still rich. The heat range of the plug has NOTHING to do with how hot the mixture in the cylinder burns, it has to do with how the plug burns off the deposits that get on the insulator during combustion. Quote Link to comment Share on other sites More sharing options...
tedd1 Posted April 2, 2011 Report Share Posted April 2, 2011 When we say "a colder plug" we are referring to the heat range the plug was designed for. Fuel type, chamber shape, squish, and more all play a role in dictating what heat range plug is to be used. From >HERE< Heat range The term spark plug heat range refers to the speed with which the plug can transfer heat from the combustion chamber to the engine head. Whether the plug is to be installed in a boat, lawnmower or racecar, it has been found the optimum combustion chamber temperature for gasoline engines is between 500°C–850°C. When it is within that range it is cool enough to avoid pre-ignition and plug tip overheating (which can cause engine damage), while still hot enough to burn off combustion deposits which cause fouling. The spark plug can help maintain the optimum combustion chamber temperature. The primary method used to do this is by altering the internal length of the core nose, in addition, the alloy compositions in the electrodes can be changed. This means you may not be able to visually tell a difference between heat ranges. When a spark plug is referred to as a “cold plug”, it is one that transfers heat rapidly from the firing tip into the engine head, which keeps the firing tip cooler. A “hot plug” has a much slower rate of heat transfer, which keeps the firing tip hotter. An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing changes, use of alternate fuels, or sustained use of nitrous oxide, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. 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. The heat range numbers used by spark plug manufacturers are not universal, by that we mean, a 10 heat range in Champion is not the same as a 10 heat range in NGK nor the same in Autolite. Some manufacturers numbering systems are opposite the other, for some manufacturers (Champion, Autolite, Splitfire and Bosch), the higher the number, the hotter the plug. For othe manufacturers (NGK and Denso), the higher the number, the colder the plug. Do not make spark plug changes at the same time as another engine modification such as injection, carburetion or timing changes as in the event of poor results, it can lead to misleading and inaccurate conclusions (an exception would be when the alternate plugs came as part of a single pre-calibrated upgrade kit). When making spark plug heat range changes, it is better to err on the side of too cold a plug. The worst thing that can happen from too cold a plug is a fouled spark plug, too hot a spark plug can cause severe engine damage It is generally accepted that, when you change to alky, you go to a colder range plug. Quote Link to comment Share on other sites More sharing options...
EZ2FLEE Posted April 2, 2011 Report Share Posted April 2, 2011 Basically the heat range on a plug doesn't mean it burns hotter or colder per number, its the plugs ability to dissipate heat from the cylinder Quote Link to comment Share on other sites More sharing options...
andrew3160 Posted April 8, 2011 Report Share Posted April 8, 2011 I am running 9's on a 4 mill with 21cc domes and stock carbs if that helps. Was recommended by fast when they built the motor. Quote Link to comment Share on other sites More sharing options...
vizmark Posted April 11, 2011 Author Report Share Posted April 11, 2011 I am running 9's on a 4 mill with 21cc domes and stock carbs if that helps. Was recommended by fast when they built the motor. Interesting. Any problems with fouled plugs? Quote Link to comment Share on other sites More sharing options...
BigRed350x Posted April 12, 2011 Report Share Posted April 12, 2011 Run 9's for meth and spray, and the 8's for everything else. Quote Link to comment Share on other sites More sharing options...
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