In Reply to: Re: What Spark Plugs should I use for my 1989 535i posted by dave on February 22, 2000 at 21:04:47:
: I contacted the bosch tech folks and the guy i talked to said he highly reccomended the plus 4 plugs.
Fancy that. The Bosch tech guy recommended a Bosch product. And the expensive one, to boot.
Check this out. Electricity arcing across an air gap will take the path of least resistance. So, if one of your four ground electrodes is even a trillionth of an inch closer to the center electrode than the three others, the spark will go there. Always.
Bosch makes good products but the multiple/split ground electrodes commonly found on the higher dollar plugs are so much snake oil, IMHO.