PLUG READING FOR A NITROUS MOTOR

[John_Heard]

My take on those is you have a hot plug, too much fuel and not much timing in it. Not much color on the porcelain, but black sooty on the base. I don't see any timing line. You might want to go to a colder plug when you're running this at the track. Do you have an O2 sensor?

[GT4X]

Thanks for the reply, yes actually I do have the O2 sensor still in there.

[John_Heard]

What's it telling you?

[GT4X]

What's it telling you?

At WOT the AFR is approx. 12.1, these 2.2 DOHC VTEC Honda motors likes to idle on the rich side in the 13.4 AFR range. From looking at my plugs would you say the sooty base is normal for a street driven motor?

[John_Heard]

Even for a street driven car that looks pretty rich - going by the black soot on the base of the plug. The reason the porcelain isn't showing pig fat is that it's a hot enough plug to burn off the deposits I believe.

[GT4X]

Even for a street driven car that looks pretty rich - going by the black soot on the base of the plug. The reason the porcelain isn't showing pig fat is that it's a hot enough plug to burn off the deposits I believe.

Thanks! Well I have a set of BKR8EIX, i'll try em out also i'll pull some fuel and tonight i'll post some pics of those.

[GT4X]

These are a set of brand new Denso Q20PR-U11, I need to run hotter plugs on the street the 8's were killin me on the cold starts. Still rich I know.



Any timing line??

[John_Heard]

I can just see some change in color on them about 1/4" from the tip or so best I can tell. Might want to get another pass on them to show up a little better.

[Clutch]

Like I said in my first topic I came here mostly because how to read plugs, here is a picture of a plug from my engine, is not a nitrous car but still have plugs lol
I have some doubts and I want to discuss this here.

The picture:



By the way I understand the way how to read plugs I can say that my engine has:

- Too much timing
- Lean mixture
- And this spark is too cold for my engine

Just have a look at my picture and say to me what you people see besides that or correct me if my reading is wrong.

[John_Heard]

It does look at bit hot on the ground strap but the top threads look cool, typically if it's getting real hot you'll see some discoloration on the top threads too.

Is it an extended tip plug? Hard to tell on the mixture as we can't see down inside the plug from that picture. What you want to look at is the very bottom of the porcelin and look for a fuel ring there. That will show your mixture at wide open throttle. The upper half of the porcelin is what colors up at part throttle and idle - which appears to be real clean or you have a hot plug.

[Clutch]

The plug on the picture is a NGK BKR7EIX-11 I think is a non extended tip plug.
Inside the porcelin there is no fuel ring and that is why I think is lean correct me if I'm wrong.

I change the plugs for the original ones BKR6E-N-11 aswell the fuel/ignition maps for the original to see what I get and start tuning every thing again if I has to

My car has a NA engine and the picture above is with AFR at 13.3~12,8.

Standard AFR reading is 13.3~11,8 at WOT

[John_Heard]

Correct if you have no fuel ring it's pretty darn close or too lean. Sounds like to me you're at a point where you should try a little more fuel and/or take away some timing and see how the car reacts MPH wise. Start experimenting going both ways a little and see what it likes.

[Clutch]

Thanks very much

I'm trying that setup now see if i get a decent fuel ring

[azjulian]

Hi new to the forum, read the thread - thought I'd attach a pic of my #1 cycl plug, this is pump gas.

Is my timing in range, as I see to distinct bands on the plug?

[John_Heard]

That's pretty darn distinct! Why is the base ring and strap so black? Is it oiling that cyl?