Why change gap on Spark Plugs?

[FullThrottle]

Hi All,

I will be getting new spark plugs soon after the vehicle is tuned. But I see people talking about gap-ing their spark plugs to .18. Can anyone explain why? Also what is the stock gap? Any info will be greatly appreciated. Thanks!

[BMWDriverX]

I think the stock plug is around .030" and I brought mine down to .020 for my stage 2 set up. The reason for a tighter gap on the plugs is when you make more power, you're burning more fuel and you need the spark to be smaller and more concentrated. See below:

A wide gap creates a longer spark arc but without sufficient "juice" from your ignition system, (including amps), can be weak. A small intense spark is MUCH better than a big, weak spark, especially when dealing with richer fuel mixtures and more volumes of fuel being burned.

[FullThrottle]

Originally Posted by SoCalM6GC

I think the stock plug is around .030" and I brought mine down to .020 for my stage 2 set up. The reason for a tighter gap on the plugs is when you make more power, you're burning more fuel and you need the spark to be smaller and more concentrated. See below:

A wide gap creates a longer spark arc but without sufficient "juice" from your ignition system, (including amps), can be weak. A small intense spark is MUCH better than a big, weak spark, especially when dealing with richer fuel mixtures and more volumes of fuel being burned.

OHHHHH, Awesome thanks, much appreciated brother!!