How To Pass Emissions?
11-28-11, 02:21 PM
#1
How To Pass Emissions?
I live in a state that unfortunately requires emissions testing. Only the sniffer.
No visual.
I am running a halfbridge, with premixed E85. A Corvette air pump and a old cat I had laying around.
I took it in with all this hooked up and tried to lean it out the best I could.
It failed in most areas, but passed in a few.
Here is what I am thinking as my next steps because they have revoked my registration until I get it to pass.
-#1-Maybe my cat is bad? You can see through it when you put it up to the light, but when I had it on there, it got glowing red hot. I'm wondering if that burned it up?
-#2-Put some E98 in there WITHOUT premix? I'm wondering if the premix is causing it not to pass? Also wondering if it would hurt to run it just for a little while without premix.
Anybody have any ideas they could throw my way?
HELP!
Thanks!
No visual.
I am running a halfbridge, with premixed E85. A Corvette air pump and a old cat I had laying around.
I took it in with all this hooked up and tried to lean it out the best I could.
It failed in most areas, but passed in a few.
Here is what I am thinking as my next steps because they have revoked my registration until I get it to pass.
-#1-Maybe my cat is bad? You can see through it when you put it up to the light, but when I had it on there, it got glowing red hot. I'm wondering if that burned it up?
-#2-Put some E98 in there WITHOUT premix? I'm wondering if the premix is causing it not to pass? Also wondering if it would hurt to run it just for a little while without premix.
Anybody have any ideas they could throw my way?
HELP!
Thanks!
11-29-11, 05:21 PM
#2
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numbers would help....
basically with a cat you do want the mixture to be about 14.7:1. if you're richer, HC and CO will come up. if you're leaner HC and CO go down, until the engine starts misfiring, and then they will be really high, while NOX will come up.
generally the NOX limit is high, and the HC limit is low...
i've found that timing has very little effect on HC and CO, but more timing = more NOX
the overlap the bridge adds is bad, its like taking an engine with a huge EGR valve and making it bigger, the BRAP BRAP is misfire because there is too much exhaust gas in the chamber. worst case i guess you block off the secondary ports...
i don't know what effect E85 has on emissions, i've googled it, but didn't come up with anything concrete.
you may also want to try using port air instead of running it to the cat. look in the FSM for that one
good luck! you should be able to get it to pass, actually, but its a bit of a balancing act
basically with a cat you do want the mixture to be about 14.7:1. if you're richer, HC and CO will come up. if you're leaner HC and CO go down, until the engine starts misfiring, and then they will be really high, while NOX will come up.
generally the NOX limit is high, and the HC limit is low...
i've found that timing has very little effect on HC and CO, but more timing = more NOX
the overlap the bridge adds is bad, its like taking an engine with a huge EGR valve and making it bigger, the BRAP BRAP is misfire because there is too much exhaust gas in the chamber. worst case i guess you block off the secondary ports...
i don't know what effect E85 has on emissions, i've googled it, but didn't come up with anything concrete.
you may also want to try using port air instead of running it to the cat. look in the FSM for that one
good luck! you should be able to get it to pass, actually, but its a bit of a balancing act
11-30-11, 07:49 PM
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02-20-12, 04:46 PM
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02-21-12, 03:28 PM
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so you're saying if i put the electric airpump and a cat on the P port, i'll be in the ball park? that's tempting!
02-21-12, 05:32 PM
#12
car setter on firer
ya, i usually just run 120KPH down the freeway with a potato stuffed in the thermal reactor. then the sniffer only smells french fries and fools it. (premix can cook potatoes, its fun, but not delicious.)
02-21-12, 06:05 PM
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