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mike100 · 03-02-2011

It seems the NOx (and the other limits too) are based on county. Some people are held to higher limits. What year is your car? mine had a limit of 750 on high speed NOx the last time it tested- it's a 91 model year.

The NOx is mainly ign timing and engine load dependent- (combustion temps to be exact). So they let you by with headers?

Also, once the cat gets hot, did you feel that it wasn't staying hot? Usually HC and CO is easy to pass if the valve seal and compression are healthy-then it's just finding lambda on the fuel mix. Mostly NOx issues worry me because the 3-way part of the catalysts that deal with that do not have a lot of capacity and deactivates kind of easy compared to HC scrubbing ability.

I have a collection of LS3 catalysts that I'd love to graft onto some manifolds like that.

03-02-2011	#2
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,786	Re: Passed CA Emissions It seems the NOx (and the other limits too) are based on county. Some people are held to higher limits. What year is your car? mine had a limit of 750 on high speed NOx the last time it tested- it's a 91 model year. The NOx is mainly ign timing and engine load dependent- (combustion temps to be exact). So they let you by with headers? Also, once the cat gets hot, did you feel that it wasn't staying hot? Usually HC and CO is easy to pass if the valve seal and compression are healthy-then it's just finding lambda on the fuel mix. Mostly NOx issues worry me because the 3-way part of the catalysts that deal with that do not have a lot of capacity and deactivates kind of easy compared to HC scrubbing ability. I have a collection of LS3 catalysts that I'd love to graft onto some manifolds like that. Last edited by mike100; 03-02-2011 at 06:50 PM.