Getting ready to tuneup my 93 civic dx hb and am curious: Do more grounding electrodes make a difference? Are 2 better than 1 and are 4 better than 2? I do feel there would be an advantage for having the platinum. With these 100,000mi plugs, has anyone heard if they are still effective at 50 or 75000mi? Thanks! Rick
If you go for OEM Platinums then yes, because the manufacturers now sell cars that don't require a tune up for 100,000 miles. A friend of mine just replaced his spark plugs in his 97 T Bird and after ~125,000 miles the stock plugs and ignition wires were still in there. He replaced them and now says the car has a lot more power, but it didn't run "bad" to begin with, and it still passed state emissions with the old plugs and wires. As far as multiple electrodes goes, electricity always follows the shortest path to ground. This means after a period of time it will probably only fire off of one electrode anyway.
In my opinion the platnum+(insert number here) plugs aren't worth the price. In a car with a distributor such as yours, they probably wouldn't hurt. However, they probably won't help any either. I know in a car with a DIS ignition system with a waste spark, they have been know to cause misfires (happened to me and a few people i know).
Also, up until recently I worked at a parts store. With the platnum+ plugs being such a high profit item we were given spiffs of 50 cents per plug. So, depending on the sales person, they may try to force them on you.
Exactly. Its a gimmick, nothing more. The only way the spark will split 2, 3, or 4 different ways is if the resistance is exactly the same to all electrodes. If the resistance is slightly higher on one or more electrodes those will not spark. Years ago I tried Splitfire plugs (2 electrodes) on my Buick. Absolutely no performance or MPG gain, but @ $5/ea they did make a noticeable dent in my wallet.
I recommend using platinum because of the 100,000+ mile change interval. I have ran several sets of platinum plugs in excess of the 100,000 mile recommended change interval with no negative effects in FE or power. The cost of platinum's are only about $2-$3 a plug and last 100,000+ miles. Copper core plugs are $1-$2 each and have a recommended change interval of about 15,000 miles which makes the platinum more economical to use. I could be wrong about the change interval on copper core, I just know that is what was recommended years ago when I used them.
Yeah, it seemed I was putting new copper plugs in my vehicles every 12 - 18 months. When I switched to platinum I was able to extend it to several years. Now that I've switched to OEM platinums I haven't worn any of those out yet.