Which plug looks the best?

[blaster003]

270 on left 280 in middle 290 on right end I didn't have much room at my house to get up in 5th but what looks the best I'm doing my science fair project on this and I need to know which one is best this is for a fmf powercore 2 kandn filter no lid and stock pilot jets and air lid removed what do you guys think

 

[jus_me]

Where's the pic ?

 

[blaster003]

 

[blaster003]

The 290 bogs a little

 

[Blaaster]

My preference is the #280.

Is the float level correct as your mods seem to call for a bigger jet?

 

[jus_me]

All the way to the left or the middle one. Are you mixing oil and gas yourself or is the pump doing it for you?

 

[Awk08]

Only the right one is even showing signs of a smoke ring at the base of the insulator, as a proper plug chop should produce.

The color at the tip don't mean shizzle, and definitely didn't require the threads cut off to see.

Hence the name "plug chop".... Wide open then chop the throttle, and chop the threads off the plug to veiw the smoke ring at the base of the insulator produced by the full throttle/load run.

Like I said above, only the one on the right is even showing signs of a proper and readable smoke ring.

I'd be finding somewhere longer to do proper 5/6th gear wide open pulls.

This is what your looking for.....
Smoke ring

 

[best]

Yup, what AWK08 said...

You have to run those plugs longer and harder to get a smoke ring on the bottom.
It takes full throttle and fully warmed up engine to get it down there.
If the engine is warmed up and run hard the oil mixture won't affect it either.

The reason it works is because it is a cool protected area in the engine. Rich mixture produces a sooty flame and the plug insulator base will keep the evidence of that. It takes full throttle to make the cylinder pressures to drive the soot down to the base of the plug. Good for use because it is full throttle we want to know about. Lean mixtures produce a hot sootless flame.

The carbon deposits toward the tip of the plug are more a factor of plug heat range (getting hot enough to burn off deposits) and are only valuable after a very long hard run. There is little reason to change from an NKG "8" series plug.

Once you know what you are looking for you will learn how to find it without cutting plugs, but cutting plugs is the best way to learn and know. Small price for a good education. Small price to save an engine. You can also read the soot on the steel parts of the plug, but is not as clear as the insulator base.

Steve