I've heard/read from many people that reading sparkplugs is one of the best ways to know how your motor is running. Its also something they teach at the efi101 course. I've been reading up on it and found an informative post here:

http://www.dragstuff.com/techarticle...-pictures.html

Here are pics of my NGK R5672A-8 sparkplugs, mileage from my plugs are about 300-400miles

from what I gather my cylinder 4 + 3 have some signs of pre-ignition from the white specs, while cylinder 2 + 1 have no specs at all. (I'm thinking it could be from the uneven flow from the manifold) I may try to increase fuel on cylinder 3 + 4 on the kpro by 1-3% or is it that cylinder2 is to lean.

Please reply if anyone has any advice on reading my cylinders,
We could even make this a plug reading thread!

cylinder4


cylinder3


cylinder2


cylinder1

 

From my observation #1 looks good and #2 looks a little leaner but still pretty good. 3/4 I see detonation but look sooty to me also like they are getting plenty of fuel. What are your afr showing you? I might be inclined to retard the timing just a bit.

 

Thanks for the input! I was quite suprised to see the difference between all of them too...

14.7 light cruise

13.0 + boost pressure

11.2-11.5 high boost 1.1 bar in 4th gear.

in 6th gear I see 10's at high boost/load

 

Yeah pretty irregular, uneven flow of injectors comes to mind first. Your turbo I am gathering also though and that ads to some irregularity that I am not as accustomed too, such as boost fluctuations during your power curve. I'm SC and that's a bit easier to tune with since boost is always consistent per rpm.

I should mention that it is possible to get some detonation from running to rich as well. 11.5afr is rich, but not overly so, I wonder if you are getting some detonation in the very high rpm's when you start getting into the 10's? Notice how those 3/4 plugs are also sootier then the others. Maybe 1/2 injectors are flowing less. With your current afr I would be inclined to replace your 3/4 plugs and drop a few degrees of timing and check them again and see how they look, if they look great then bump up the timing another degree and figure out where you can run max safe. If you start changing fuel and timing then it gets hard to remember where you were and what you have done sometimes, unless you are comfortable doing that, you can always wright down what you do I guess, your afr will change a bit when you move your timing. These are just some suggestions/thoughts that come to mind.

 

I found this quite enlightening: http://bbmoto.net/wiki/index.php?ReadingSparkPlugs
The "from:" link at the top goes to the original thread with some good discussion as well.

 

Good little read