Impossibly low emissions?

( snipped-for-privacy@trailing-edge.com) scribbled:

my recent inspection, which they said did really good: (Texas inspection) Standard Current Reading HC (ppm) 179 41 CO (%) 2.22 0.01 CO2 (%) 14.6 O2 (%) 0.0 Nox (ppm) 1161 273 Dilution (%) >6.0 14.6

this is a '90 Trooper v6(Chevy engine), 198k miles !

Emissons tests are mostly bullshit as cars are already pretty clean if they are in tune. In the beginning, the tests only weed out way out way out of tune cars in most situations with the exeptions of cars that are tuned to maximize gas mileage (such cars run lean and thus have high NOx volumes.

Grams per mile? This is a conversion. Probe measures ppm.

This may be high. Indication is that you are running rich and the catalitic is cleaning up the unburned HC that is coming out the tail pipe

This is too low, again, your car is running rich. I have run cars that passed witn 1550 ppm at 25 mph with the limit set at 1668 pm for the test. The car was running 26 miles per gallon. Retuned to a richer mix on the following test, the mileage dropped to 24 mph with a slight increse in hc leves. I leaned it out again. With gas prices the way they are, I like to get the extra 10 %. If they want clean air, confiscate barbara treissand's private jet.

Don't worry, the EPA will be reducing the limits in the near future.

I agree. All those extra (and unnecessary) trips everyone has to take to the emission inspection stations probably generate more pollution and waste more fuel than catching the

What the heck is GPM? I've heard of PPM but not GPM. Maybe the decimals are right for whatever the heck GPM is.

"ed" wrote in news:d5d5gc$fmu$ snipped-for-privacy@tomm.stsci.edu:

grams maby????

Actually, grams per mile. I don't think my vehicle has any idle testing required, it's all dynamometer testing.

Tim.

( snipped-for-privacy@trailing-edge.com) scribbled:

... Texas tests that way (dyno) too, at two different RPM settings. (but in Texas, the reports are in PPM or % - see my other post in this thread)

My guess would be "Grams Per Mile."

GPM = grams per mile, not "grams per million". GPM (more properly abbreviated g/mi) is how the Federal emissions certification tests are set up.

GPM= grams per mile. The actual mass of the pollutant in question is measured over a distance. Usually measured with a "flame ionization detector," which is fairly expensive. PPM= parts per million, percentage is the same thing at a different scale. Usually measured with a "non-dispersive infrared test cell," which is fairly cheap. PPM equates to how many bubbles are in a bar of soap since you can have an absolutely filthy reading, but if you dilute it with an air pump or a pulse air system, it will appear much cleaner. PPM and percentages do have great use when used for diagnostic purposes, but this is because all five gasses are compared against each other in order to determine whether the mixture and combustion efficiency are correct.

I'm with you -- there's something cockeyed about the decimal place or the instrument or the test procedure, one. The only other explanation would be a massive exhaust leak upstream of the tailpipe, something that should be trivial to either identify or rule out.

Not that a well-kept 1992 Saturn isn't a nice little car, but the numbers quoted to you are better than a recent-model Ultra-Low-Emissions Vehicle, and in fact are in or near the Super-ULEV realm that is occupied mostly by hybrids (see for instance

Cheers,

--Joe

"Emissons tests are mostly bullshit as cars are already pretty clean if they are in tune."

I disagree. If you don't have some sort of policing of pollution standards then there is no incentive for drivers to keep their cars in tune and sensors and converters working. Are you going to depend on voluntary compliance..."I promise to make sure my car is kept running right..."

I think the standards should be tightened for older cars, and if they fail and can't be repaired then they should be removed from the road. No paying $100.00 in repairs then going on.

Well, why not? That's what the present administration does for industry.

Oh? And what data do you have to support your litle belief here? A '77 Caprice you saw two weeks ago, belching smoke? The "common knowledge" that old cars are all a bunch of gross polluters? You were scared by a '73 Mustang when you were small? Please elucidate.

That is sure true. In fact, even with laws, look at commercial operators. Some of the Diesel trucks around here are WAY overdue for maintainance. Owners just don't car. I suspect the fine for excess emissions may be less than the cost of a tuneup on these big rigs. Or else they are just gambling that they won't get caught. We have opacity laws here, and still the trucks spew out stuff that literally blocks out the sun sometimes.

Well, fortunately you're not in charge. I have no problem holding older cars TO THE STANDARDS THEY WERE BUILT TO. But its just stupid to tighten the requirement on them, especially when over 90% of all automotive pollution comes from cars less than 10 years old. Its a numbers game- there are so few old cars on the road that they just DO NOT contribute to the total pollution in any measurable way at all. And most of them do run relatively clean, because they're well-cared-for collector cars.

like my boat, gallons per minute!

Actually, I had a car pass under GPM but fails when they go to PPM. Go figure.