Well I'm still trying to figure out why I failed NJ smog for slightly high NoX.
So I figured I'd do some long overdue maintanence
Plugs, cap, rotor, fuel filter, top engine cleaning, etc.
I pull out the old plugs and those brain surgeons at [...........] Honda, had put in BCPR 5E Y N11.........the standard plugs for the HF.
The Si uses BCPR 6E 11. One step colder.
Would this change cause the NoX to be high?
Or did it contibute to the high combustion chamber temps? Or carbon build up?
The plugs themselves LOOKED beautiful, nice light cocoa brown, even though the gap was a little wide.
Any ideas?

 

ttt

 

Try a bottle of "guarantee emissions pass" available at any auto store...get the cat nice and warmed up and then immediately go for the test.

Something else to consider, our cars are typically 150k+ miles...the stock cat has seen better days. A defective three-way catalytic converter may result in high NOx emissions.

As far as spark plugs...
I went one heat range colder when I advanced my timing and saw benefits all around. Here's a good break down:
http://www.sentra.net/tech/sparkplugs.php

I also pulled this from an NGK FAQ I had saved...
*****************************************
As you can see, our heat rating number goes up as speed, load and temperature go up. In other words, higher numbers are colder plugs. A colder plug simply has a better ability to cool itself. When combustion chambers become more violent (higher temps) due to aftermarket toys, the plug sees higher temperatures approaching its critical temperature (~900 degrees C). To avoid plug failure (burning away ground / center electrodes, or just increasing the plug's gap) some people must go to a colder plug.

The reason we cannot use a colder plug from the outset is fear of never getting the plug warm enough. A spark plug must reach what is called its "self-cleaning temperature" (or region) which generally occurs at about 500 degrees C depending on the A/F ratio. This is normally reached during high engine or vehicle speeds. This "self-cleaning temperature" allows the plug to burn off carbon deposits accumulated at lower speed and idle conditions. If this temperature is not consistently reached, you will have definite fouling problems.

Most appications that are not burning oil and are subjected to poor quality gasoline can possibly benefit from going to a one-step-colder heat range spark plug, especially if the vehicle has a tendency to 'ping' under load or while climbing a hill.

There are situations, though, that may require a slightly hotter or colder plug than the one normally recommended. Switching to a slightly hotter plug can help reduce fouling in an older engine that uses oil, for an engine that spends a lot of time idling or is used for short trip stop-and-go driving. But a hotter plug should not be used unless an engine is experiencing a fouling problem because of the increased risk of preignition and detonation.





Modified by davens at 3:59 PM 6/15/2004

 

Good info.
Thanks man.