CA Smog Numbers
 

So my car just passed Smog (always a happy day) and I'm wondering what I can glean from the numbers. I'm trying to make sense of the percentages to tell if the car could be running better. 1982 SC with 90K miles.

Thanks


http://forums.pelicanparts.com/uploa...1522429459.jpg

Your catalyst looks like it’s working very well (HC) and all your other measurements look low, right where you want them. I’d say your car is doing just about as well as it could be, time to keep driving it.

Thank you. The numbers were so low I wondered if it was running lean?

cheers

Ditto. Can’t get much better. The CO2 levels are high indicating peak efficiency.

I have kind of a followup to this. My engine doesn't have any O2 sensor or emission control, so I run @ about 3.5% CO, as recommended by John Walker. In a car like the OP's is there any advantage at all to try to up the CO where permitted? Is this even possible with the emission controls in place? Will it yield any more power? Or will it screw up other things, eg the cat converter?

Just wondering...

Which one of the numbers in my smog test represent this 3.5% CO? Is there a decimal point missing somewhere?

deguitars,

You're not missing anything. Your CO and other numbers are very good, which shows you have a correctly functioning emission system. The 3.5% number I mentioned is for cars w/o controls, like mine. My question was kind of blueskying, in that, since an uncontrolled engine seems to work best @ about 3-3.5%, is there any advantage in terms of power, to try to get that CO figure up. Or will it yield negative results, such as clogging a catalytic converter or otherwise throwing your other figures off.

Say for example you live where you can run @ 1.5% CO with a cat, is there any reason to try to increase the figure to 1.5? Alternatively, if you live in an area where your emissions are not measured, is there any reason to go to say 3.5 with a cat,rather than just removing it?

Just a question for those with tuning experience.