Headers , Exhaust and emisions in Colorado

[4-cam]

Well I passed emmisions! With my previous chip I was not even close. Ported top end, secondaries removed, SW long tube headers, x pipe , magnaflow cats and 3 " exhaust was a bit to much change. I contacted Dominic and he had a tune from an earlier round of modifications on his car that was simular to mine. He made some minor changes for my application and first time thru it passed.
I think this really shows how good Dom 's tune was as he does not have to pass emissions in Chicago. I believe if the A/F ratio is kept in check thru out the rpm range thru a good tune , then emmisions should not be a problem with these modifications.
THANKS AGAIN DOMINIC.

[XfireZ51]

I'm glad it worked out. How do the plugs look? Any numbers on the emissions test?

[Franke]

Good job Darby. I'm relieved to hear that so that if some day my cats fail I can go aftermarket with headers etc. I don't know Dominic but good work there too.

[4-cam]

Emissions readings: failed HC in original test
Limit for HC- 1.5 gpm
Failed test-3.6 gpm
Passed - 1.27 gpm

CO limit-20 gpm
Failed test-1.1092
Passed-1.1701

NOx limit-3.5 gpm
Failed test-2.3
Passed-2.7

Colorado has this goofy grams per mile reading. No real way to convert to ppm as a 5 gas analyzer would read.


After i put a few more miles on it today I dont think im done yet but at least emmisions is done . I can work on it and be legal.
Plugs are still looking to hot. Even with colder ngk bkr7e plugs they are grey/ white. I dont think its a tuning issue at this point. I think somthing else may be going on. When we first put the new tune in it it seemed to run great. The more I drove it , it seems go run rough, and the flywheel starts to make noise. I shut it down, reset power to the ecm and restarted it and it smoothed out and ran better. No codes were set. Then started doing it again and repeated the cycle after a out 1/2 hr of drive time. Could the ecm be pulling fuel out for some reason? From previous data logs the O2 sensors seemed ok and the curent ones only have about 2k miles on them.
Anyone have any ideas? I didnt get any data logs during my last run, so I need to put a few more miles on it and do so.

[XfireZ51]

Actually grey is not a problem. It has to do w the ethanol,and additives in the gas. If ur expecting light tan, that's not necessarily the case any longer. To truly judge u should do a "plug cut" removing the threaded portion of the plug and looking at color. My plugs are not tan.

[XfireZ51]

Did it do this w precious cal? Where is the MAT sensor and how does outside temp affect how it runs over time?

[Schrade]

Originally Posted by 4-cam

Emissions readings: failed HC in original test
Limit for HC- 1.5 gpm
Failed test-3.6 gpm
Passed - 1.27 gpm

CO limit-20 gpm
Failed test-1.1092
Passed-1.1701

NOx limit-3.5 gpm
Failed test-2.3
Passed-2.7

Colorado has this goofy grams per mile reading. No real way to convert to ppm as a 5 gas analyzer would read.


After i put a few more miles on it today I dont think im done yet but at least emmisions is done . I can work on it and be legal.
Plugs are still looking to hot. Even with colder ngk bkr7e plugs they are grey/ white. I dont think its a tuning issue at this point. I think somthing else may be going on. When we first put the new tune in it it seemed to run great. The more I drove it , it seems go run rough, and the flywheel starts to make noise. I shut it down, reset power to the ecm and restarted it and it smoothed out and ran better. No codes were set. Then started doing it again and repeated the cycle after a out 1/2 hr of drive time. Could the ecm be pulling fuel out for some reason? From previous data logs the O2 sensors seemed ok and the curent ones only have about 2k miles on them.
Anyone have any ideas? I didnt get any data logs during my last run, so I need to put a few more miles on it and do so.

Gms/MILE???

Is it based on a car's original EPA sticker?

Cause if it's the same for ALL cars, then it's an absolute, and not a ratio, and it's Nazi-esque...

[4-cam]

It did seem to do it with my original CAL, Just figured it was a tuning issue and maybe that it would resolve itself. I did not notice it on your first tune that you sent me but the longest I drove it with that tune was to come and meet up with you so I didn’t have a lot of miles on it.

I did move the MAT sensor to the air box. I did not really pay attention to how the outside temp affects it. This could be an issue as our temperatures fluctuate wildly in Colorado. Im used to it, maybe the Z is not.

[mike100]

I plug my MAT back into the air horn when i go to the smog place. mostly for visual inspection, but also because I want the less aggressive timing and fueling.

Funny your NOx went up a little on your passing run. Usually engine temps, lean fuel mix, and ign timing affect that the most.