Lowering NOx - Maybe not so difficult.

[Robert_A_Brady@domain.elided (Robert A Brady)]

As was mentioned in the previous digest, lowering NOx is not necessarily a 
simple task.  In general, things that lower NOx make CO and HC go up..... 
however.....

If you are trying to just get through emissions testing, and your CO and HC 
levels are within spec, try retarding your timing a bit.

Last summer, when our former Honda Accord was going through the new 
"enhanced" emissions testing in PA, it failed on NOx.  The local "mechanic" 
who was performing the test, said, "needs a catalytic converter."  Noting 
that the CO and HC readings were within limits, and remembering that I 
removed and reinstalled the distributer some time back, I figured that the 
timing was just advanced too far. (I didn't retime the car when I put the 
distributer back, just lined up the marks I made on it before removing it.)

When I suggested adjusting the timing, the "mechanic" himmed and hawwed (sp?) 
and refused to do it.  So, that night, I reset the timing to factory specs 
(it was advanced) and had it retested the next day.  It passed with flying 
colors. The "mechanic" was awestruck with this display of magic.

Bottom line, retard your timing and NOx will go down.  Be wary though, as you 
retard timing, CO and HC will go up.... so it's a balancing act.

Thankfully, my '74 gtv is exempt from this annual dance.  Interestingly, our 
Subaru wagon is also, as it is full-time 4wd and the dyno only works on cars 
with one set of rolling wheels..... quattro owners take note!

bob brady, dvaroc 

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