View Full Version : Spark plug gapping

09-24-2010, 11:24 AM
Hey guys, I couldn't find any other thread about this subject. My hayne's manual which seems to have been written in the early to mid 90's talks about gapping the plugs and all before replacing them.

Problem is, after purchasing the plugs for my m3, I realized their tip looks quite different. Instead of having a single metal arm that extends OVER the core, it has 4 little ones BESIDE and AROUND the core. That got me confused and I'm wondering whether these need to be gapped at all. Here is a pic:

Dr. Flyview
09-24-2010, 05:53 PM
I think it depends what they are supposed to be gapped to. Usually they are pre-gapped to a proper spec.

P.S. The ones with 4 prongs I think are the Bosch+ or something. They're pretty shit. Looks like for our engines, the most simple spark plugs are the best in terms of performance, that is, single prong copper plugs. (Platinum is shit and irridium is probably as good as copper but lasts longer).

09-24-2010, 07:35 PM
My m52 & m20 both run better with 2$ copper plugs than those ones.

Most 4 prong plugs dont need to be gapped.

09-25-2010, 12:04 PM
This is not one of the + ones, if you read the engravement it's actually a stock Bosch FGR 8 QKE and it is copper core

So should I just plug it in without gapping?