SE plugs have a finer tip and arm. Finer is less chance of fouling due to less area to soot up and also area of arc is hotter Materials are also more expensive for irridium and platinum Which resists wear and opening the gap.
http://auto.howstuffworks.com/under-the-hood/vehicle-maintenance/vehicle-care-spark-plugs.htm
But most hd tuners and mechanics will still use stock most of time because we probably change plugs more than any group of motorists
The only real advantage to the SE platinum tip plugs is longevity, same as with other platinum or iridium plugs. The material doesn't erode as quickly as the standard electrode material, thus allowing for longer change intervals. It's what makes those 60,000 to 100,000 mile plug change intervals for cars possible. However, as noted above, most Harley owners seem obsessed with changing plugs way too often (trained by decades of bogus requirements in the maintenance schedules). If people still change plugs at 5k or 10k miles and use the SE plugs, they are just throwing money away. In other words, there is no magic that makes a new SE plug perform any better than a new standard plug. All the ads showing multiple electrodes and other gimmicks plug makers claim improve performance are BS. I've explained to people many times in the past that when the plugs fire, only one spark is created no matter how many electrodes are positioned around the center electrode. It's not like a plug with three or four ground electrodes will create three or four sparks at the same time.
Study the history of spark plugs and you will find that all the gimmicks have been invented and reinvented many times. The folks building the engines and selling the cars and bikes stick with one set of electrodes for a reason, and the aftermarket pushes the gimmicks as a way to convince people to replace perfectly good plugs with those overpriced gimmicks by inferring a performance increase. Yup, if you replace any used plug with a new plug you might see better performance for awhile. It's got nothing to do with all the extra electrodes however.
Jerry
Btw, the reason I threw in all the verbiage about multiple ground electrodes is due to the fact that a previous version of the SE Sparkplug had multiple ground electrodes with platinum bits attached to them. Harley claimed all sorts of great benefits, which of course were nothing but marketing hype. Previously they offered an SE version of the old split-fire plug with the ground electrode split into a Y shape at the firing end. Also pure BS, as was the original version offered for autos. An added bonus to both the split-fire and multiple electrode plugs is that some actually had part of the ground electrode break off and rattle around in the head. Now the current version offers a fine wire center electrode and a modified split-fire design with tiny platinum nubs on each leg of the Y. I assume they will eventually offer a Harley branded SE Pulstar plug for $30 apiece, and some folks will run right out to buy those as well.
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Topic: Spark Plugs (Read 5371 times)