Originally posted by TheContourGuy:
Interestingly, I left my TH fix in while I had emissions tested. Here are the results:
Hydrocarbons: 0.113g (0.276g = standard)
Carbon Monoxide: 1.793g (1.852 = standard)
Carbon Dioxide: 1.765 (no standard given)
So I dunno what to tell you, I still passed emissions.
The emissions test done in the field does not even begin to match the testing that the automakers must go through. We can often get away with modifications that would not stand up to the more rigerous certification testing that the automakers must go through.
When testing for certification, a bag on the exhaust collects all that comes out of the tailpipe during the testing sequence. If the total pollutants (measured in grams) is too high, then the automaker tweeks up the controls a bit tighter to get the level down under legal specs.
The testing in the field only measures the percentage of pollutants coming out of the tailpipe. Depending on the local requirements, the reading may be at idle with no engine load and at 2500 RPM at no load, or it may be under load (on a dyno) at 15 MPH and 25MPH. These testing conditions only measure a very small portion of the cars actual use.
