Well it's twice now. This time I'm gonna put some numbers up so you guys can gimme so feedback.

1st Attempt: I pretty much went in with all my mods, and a hi-flow cat. These were the numbers.

Hydrocarbon (HC): 0.4033
Max Allow: 0.5000 PASS

Carbon Monoxide (CO): 1.2466
Max Allow : 9.3200 PASS

Oxides Of Nitrogen(NOx):1.5356
Max Allow: 1.2400 FAIL

So then Payam helped me fiddle around with the car a little. We use the GM Cleenz stuff, and also removed the Thermostat to make the car run cooler.

2nd Attempt

(HC) : .8054
Max: .5000 FAIL

(CO): .5526
MAX: 9.320 PASS

(NOx): 1.517
MAX: 1.2400 FAIL

So today, I took the my stock cat to the muffler shop and had them cut off the Y-pipe and bolt it on to my set up right now. So with the stock cat in place, I hope I can pass.

I think I should put the thermostat back in, what do you guys think? And is there anything else I should do as well? Time is running out for me.

 

yeah put the thermo back in ..

i was scared this would happen .. remember how i told u about reducing NOx could cause HS to skyrocket

u should really check ur EGR .. i forgot to check it while u were here ... EGR is the main cause of NOx failure ...

other than that .. stock cats are always better than aftermarket ones .. rule of thumb !! hope that helps

 

If you are failing both you are going to have to check all of your emissions hardware. Definitely try a stockish cat, and check your EGR.

Anything we suggest regarding spark timing, fan temps, water temps, etc. will only help reduce one reading at the expense of another.

 

can u pass w/o egr??

 

if u got a cam u can

 

ok got me scared for a sec

 

Are things like filling up with premium gas, and driving on the highway for half an hour before aircare, myths or do they actually work?

 

Methyl Hydrate, retarded timing, and lowered fuel pressure are all your friends... also raise your tire pressure to about 15 lbs over the max sidewall pressure. Every little bit helps

 

Requires an easy check of the EGR, your cat was fine since you passed HC, aftermarket cat won't give you awesome number for HC but you passed & thats all that matters, check you EGR, I don't think retarding timing would help at all, you will lower your HC by retarding timing but your NOX will go up, you're border line on both, the only way to do it is acctually get an EGR, with your HC numbers you want to run as hot as possible. Everything else is not worth trying at all, some would point their intake to face their headers which would lower your NOX a bit but probably wouldn't do much since you need inert gas.

Anywho I might have a working EGR kicking around.

 

I passed I passed! With a quick pass too!

The stock cat did the trick!
Just wanna thank everyone for their advice, and especially Payam for his time and help.

Cheers!

Time to bring on the cam!!!

 

Nice, weird you got better NOX readings with stock cat aswell???

 

Yes the newer 3-way catalytic converters reduce NOx emissions.

 

wow thats kinda cool.