HC PPM- emissions
Thread Starter
Melting Slicks
Joined: Sep 2004
Posts: 3,228
Likes: 672
From: Northeast
HC PPM- emissions
Just back from getting my inspection sticker. Luckily I do not have to pass emissions. My parking brake works fine 
Hc reading was high and just curious what you guys without cats get for readings?
Better still, if you had it tested with cats then without. Does the reading change drastically?
Apparently I shut the computer off with my levels. I checked the plugs last weekend and they were fine. Car idles great and there is no bog or hesitation at wot so I really dont want to change anything yet.
Thanks.
Hc reading was high and just curious what you guys without cats get for readings?
Better still, if you had it tested with cats then without. Does the reading change drastically?
Apparently I shut the computer off with my levels. I checked the plugs last weekend and they were fine. Car idles great and there is no bog or hesitation at wot so I really dont want to change anything yet.
Thanks.
Drifting
Joined: Feb 2005
Posts: 1,738
Likes: 2
From: San diego ca
HC 92ppm @ 15mph 75 @ 25 mph - on the old L-82 with an older CAT
California smog tests are done on a roller to simulate driving, as opposed to the old idle test. The rolling test is supposed to fail more cars.
on the new motor, which is much stronger than the L82 my numbers were:
...newer CAT (only 2 years old)
15mph HC(ppm) max=191 ave=47 meas=21
25mph HC(ppm) max=159 ave=37 meas=24
15mph co(%) max=1.25 ave=0.20 meas=0.01
25mph co(%) max=1.05 ave=0.17 meas=0.01
15mph NO(ppm) max=1277 ave=554 meas=570
25mph NO(ppm) max=1137 ave=468 meas=613
California smog tests are done on a roller to simulate driving, as opposed to the old idle test. The rolling test is supposed to fail more cars.
on the new motor, which is much stronger than the L82 my numbers were:
...newer CAT (only 2 years old)
15mph HC(ppm) max=191 ave=47 meas=21
25mph HC(ppm) max=159 ave=37 meas=24
15mph co(%) max=1.25 ave=0.20 meas=0.01
25mph co(%) max=1.05 ave=0.17 meas=0.01
15mph NO(ppm) max=1277 ave=554 meas=570
25mph NO(ppm) max=1137 ave=468 meas=613
Last edited by fauxrs2; Jun 11, 2009 at 09:51 AM.
Former Vendor
Joined: Apr 2009
Posts: 766
Likes: 3
From: Charlotte North Carolina 704-394-5150
Old oil ( oil that has not been recently changed before your emissions test) can elavate your HC readings.
Un-burnt fuel also raises this number.
I had a 1993 Corvette in my shop that would boil the rear tires but when it went into teh emission test it was 880 PPM of HC. After an ignition tune-up and oil change it lowered the number down to 89 PPM of HC and passsed.
Do not have any info on what you are asking due to I can not remove cats for any reason. Major fines if caught eventhough we do not need emissions tests here any more if you are Pre-1996. Cars are SUPPOSED to be like factory. I still check the cars that I tune up to make sure it is even needed.
What were your numbers? Unless you do not care to correct them at this time.
"DUB"
Un-burnt fuel also raises this number.
I had a 1993 Corvette in my shop that would boil the rear tires but when it went into teh emission test it was 880 PPM of HC. After an ignition tune-up and oil change it lowered the number down to 89 PPM of HC and passsed.
Do not have any info on what you are asking due to I can not remove cats for any reason. Major fines if caught eventhough we do not need emissions tests here any more if you are Pre-1996. Cars are SUPPOSED to be like factory. I still check the cars that I tune up to make sure it is even needed.
What were your numbers? Unless you do not care to correct them at this time.
"DUB"
