Passed Portland, OR emissions

[Toady]

I've been worried about this for a while because my car has a vacuum leak somewhere that doesn't let it idle that great on occasion. Here are my mods and the numbers (177k miles):

* stock longblock
* 160 stat
* TB coolant lines blocked
* pass side K&N breather
* stock 17-year-old cat
* Walbro 340 w/ Racetronix hotwire
* 237 FP reg
* 9" K&N behind front bumper (homemade cold air)
* Trans + w/ 3" LT1 MAF (all settings "zeroed" & base MAF on 3)
* 98 octane extender chip
* Hooker exhaust
* ported stock turbo and elbow
* 25-30% mix of xylene in tank, ~3/4 full
* adj. wastegate rod that only holds about 8 psi at WOT, solenoid vent blocked off
* drove around for about 10 min.

THC g/mi
std - 2.00
me - 1.13

NOx g/mi
std - 3.70
me - 1.06

CO g/mi
std - 32.0
me - 22.3

CO2 g/mi
std - N/A
me - 691.1

The THC and NOx numbers are better than 2 years ago when the car had less done to it, but the CO number is much higher than before. I had the stock MAF and chip, and a smoking stock turbo, for that test. Here are the numbers from 2 years ago (170k miles):

THC - 1.31
NOx - 2.36
CO - 6.2
CO2 - 574.8

Joe and Jim, all the archived emissions posts, and this section of the board in particular, helped arm me for the test, so I hope this info is helpful to someone. One thing that is confusing me - I thought my NOx would be higher using a non-EGR chip like the extender?

 

[TurboJim]

Originally posted by Toady
Joe and Jim, all the archived emissions posts, and this section of the board in particular, helped arm me for the test, so I hope this info is helpful to someone. One thing that is confusing me - I thought my NOx would be higher using a non-EGR chip like the extender?

well, if Bob's lean cruise kicked in, thats why it passed. Nox is raised with a lean mixture UNTIL somewhere around 16:1 AF, where there is too little energy in the charge to generate heat. So, despite not having an EGR valve, if the car leaned way out under steady state cruise, then thats what helped you pass.

Looking again, you werent that lean, but werent that rich... I dunno dude, but I wouldnt question the approved sticker on your window

 

[gofstbuick]

Originally posted by Toady

The THC and NOx numbers are better than 2 years ago when the car had less done to it, but the CO number is much higher than before.

Joe and Jim, all the archived emissions posts, and this section of the board in particular, helped arm me for the test, so I hope this info is helpful to someone. One thing that is confusing me - I thought my NOx would be higher using a non-EGR chip like the extender?

Since the CO went up from 2 years ago, I believe the mixture went rich. If that is the case, the rich mixture may have lowered the NOx. NOx is a somewhat difficult emission to control. It peaks after 14.7:1 (a/f mixture) up to 16:1, and falls after 16:1 and less than 14.7:1.
But I'm glad you passed. Thanks for the kudos to this section, but really this is a kudo to all the members of the whole board that participate and contribute (answering post) to it.

 

[grw]

That makes two of us Rhett! I just go thru tonight also, guys were real cool this year! I went thru with my ET Streets on, I thought I might have to prove they were DOT, but the guys did not even blink!
Lets make sure we hook up at a cruise or race again this summer, talk to you soon!