Thread: Passed CA Smog
View Single Post
Old 09-01-2004, 06:58 PM
Duke2.6 Duke2.6 is offline
Registered User
Join Date: Mar 2003
Location: Southern California
Posts: 2,270
Those are good HC numbers for a 2.6, but could be better as the O2 is fairly high, which, if consumed in the converter, would lower HC and CO. Also, your NOx is high.

Do you have the data from the last test to compare the improvement, if any?

Did you go to a drive through test only station with a short line and keep the engine revs up while waiting?

For comparison my last numbers were (HC, CO, NOx, O2):

15 MPH, 1657 revs: 113. 0.36, 261, 0.1
25 MPH, 2665 revs: 058, 0.18, 188, 0.0

If the converter was hotter during the 15 MPH test, the 0.1% O2 could be consumed to further reduce HC and CO. The 15 MPH test heats up the converter to the point where it is "100 percent efficient" during the 25 MPH test - all O2 is consumed - but the HC and CO is still higher that average for the year group. NOx is about average.

The difference in revs is because my car has a manual trans. and both tests must be run in second gear to be within the RPM limitations.

I'm due again in February, and I'm sure I will be directed to a "test only station" being as how ours cars have been tagged by the BAR as "high emitter profile", but there is a drive through test only station not far from me that is cheap and convenient, so I would probably go there anyway.

I think one of the "problems" with these engines is the semi-hemispherical combustion chamber. It has a fairly large quench area that probably increases engine out HC relative to a design with a smaller quench area.

Reply With Quote